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Dietary advice for reducing cardiovascular risk

  1. Karen Rees1,
  2. Mariana Dyakova1,
  3. Kirsten Ward2,
  4. Margaret Thorogood3,
  5. Eric Brunner4,*

Editorial Group: Cochrane Heart Group

Published Online: 28 MAR 2013

Assessed as up-to-date: 27 APR 2011

DOI: 10.1002/14651858.CD002128.pub4


How to Cite

Rees K, Dyakova M, Ward K, Thorogood M, Brunner E. Dietary advice for reducing cardiovascular risk. Cochrane Database of Systematic Reviews 2013, Issue 3. Art. No.: CD002128. DOI: 10.1002/14651858.CD002128.pub4.

Author Information

  1. 1

    Warwick Medical School, University of Warwick, Division of Health Sciences, Coventry, UK

  2. 2

    King's College London, Department of Twin Research & Genetic Epidemiology, London, UK

  3. 3

    Division of Health Sciences, Public Health and Epidemiology, Coventry, UK

  4. 4

    University College London Medical School, Department of Epidemiology and Public Health, London, UK

*Eric Brunner, Department of Epidemiology and Public Health, University College London Medical School, 1-19 Torrington Place, London, WC1E 6BT, UK. e.brunner@ucl.ac.uk.

Publication History

  1. Publication Status: New search for studies and content updated (no change to conclusions)
  2. Published Online: 28 MAR 2013

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This is not the most recent version of the article. View current version (06 DEC 2013)

 
Characteristics of included studies [ordered by study ID]
Ammerman 2003

MethodsCluster RCT in rural North Carolina, USA. County health department was the unit of randomisation. Randomisation was stratified by region (East/West) because of known demographic differences. All comparisons between study groups controlled for randomisation by health department by using mixed-effects linear models. This approach adjusts for any lack of independence among observations from patients within each health department. Analysis was at individual level, allowing for random effects of the health department. The denominator used in this review is the health department.


ParticipantsParticipants with untreated hypercholesterolemia (total cholesterol >180mg/dL if checked in the last year), aged 20-70 years, resident in the community and contactable by phone. Excluded participants on treatment for hypercholesterolemia (defined as taking lipid lowering medication or more than 2 diet counselling sessions by a health professional in the last 6 months), severe medical conditions, inability to speak or comprehend English. Participants were recruited from county health departments, there were 8 clusters (216 participants) in the intervention group, 9 clusters (252 participants) in the comparison group. The mean age was 54.5 years, and 29% of the participants were men.


InterventionsFood for Heart Programme. All participants had a dietary risk assessment using a validated FFQ, the primary goals were to reduce the consumption of saturated fat and increase consumption of fruit and vegetables and complex carbohydrates. The programme comprised 3 counselling visits from public health nurses using the Food for Heart Programme - a theory based dietary assessment and tailored counselling programme for lower income patients with high cholesterol. The intervention used the dietary risk assessments, illustrated goal sheets, educational pamphlets and a southern style cookbook. Visits took place at 0.5, 1.5 and 2.5 months. Due to >20% loss to follow-up at 6 and 12 months data is only used in this review for 3 months follow-up. After 3 months if cholesterol was still high participants were referred to a nutritionalist and at 6 months there was further re-inforcement with phone calls and newsletters. The comparison group received a minimal intervention which comprised a dietary risk assessment by public health nurses and the nurses were instructed to provide counselling for high cholesterol as they usually do. The cluster design ensured the groups were not contaminated.


OutcomesTotal cholesterol, LDL cholesterol.


NotesOnly data at 3 months follow-up were used due to high loss to follow-up subsequently. Authors were contacted to provide data on HDL and triglycerides which are presented only in figures in the paper. They responded that they would try but have not yet provided this additional data.


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskMethod used not stated. Randomisation was stratified by region (East/West) as demographic characteristics differed.

Allocation concealment (selection bias)Unclear riskNot stated.

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskNo details. Cluster randomisation avoids contamination.

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskUnclear risk for outcomes of interest. Low risk of bias for dietary assessment questionnaire as interviewers were blinded to participants study group.

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskHigh risk of bias for 12 month data as high losses to follow-up. 3 month follow-up data used in the analyses.

Selective reporting (reporting bias)Low riskAll expected outcomes reported.

Other biasUnclear riskInsufficient information to judge.

Anderson high fibre

MethodsRCT of parallel group design. The control group N is halved to take account of the 2 intervention arms.


ParticipantsHigh risk - total cholesterol 5.2-7.8 mmol/L on 2 screenings 2 weeks apart. Recruited from major employers, churches and shopping centres in the USA. 177 participants randomised, 59.6% men, mean age 40.6 years.


InterventionsTwo interventions - both AHA-type cholesterol lowering diets. This trial arm included a high-carbohydrate fibre diet (50 g/day). Both arms included a 10 week diet education seminar series (1 hour/week) followed by 30 minute individual counselling sessions, plus 4 home visits from dietitians. Comparison group received no intervention. Follow up at 12 months.


OutcomesDietary fibre, total dietary fat and saturated fatty acids (% Kcal), total, HDL and LDL cholesterol.


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskSee Table 1

Allocation concealment (selection bias)Unclear riskSee Table 1

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskSee Table 1

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskSee Table 1

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskSee Table 1

Anderson low fibre

MethodsRCT of parallel group design.


ParticipantsHigh risk - total cholesterol 5.2-7.8 mmol/L on 2 screenings 2 weeks apart. Recruited from major employers, churches and shopping centres in the USA. 177 participants randomised, 59.6% men, mean age 40.6 years.


InterventionsTwo interventions - both AHA-type cholesterol lowering diets. This trial arm included a recommended approximately. 15 g/day fibre diet. See 'Anderson high fibre' for further details of intervention. Follow-up at 12 months.


OutcomesDietary fibre, total dietary fat and saturated fatty acids (% Kcal), total, HDL and LDL cholesterol.


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskSee Table 1

Allocation concealment (selection bias)Unclear riskSee Table 1

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskSee Table 1

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskSee Table 1

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskSee Table 1

Anderssen 2007

MethodsRCT of parallel group design.


ParticipantsRecruited from a community screening programme in Oslo, Norway. Participants (all men) had the metabolic syndrome (IDF definition) so were at high risk of CVD. Patients with CVD or diabetes or on drugs that would interfere with the test results were excluded. The study was a retrospective analysis of the Oslo Diet and Exercise study in men who met the definition of metabolic syndrome. Their mean age was 44.9 years. 34 participants were randomised to the diet only arm and 26 to the control arm.


InterventionsParticipants were randomised to diet only, exercise only, diet and exercise or control. Data are only analysed for the diet only and control arm in this review. The number of participants randomised to the control group was divided by the number of intervention groups to take account of this in the analysis. The diet only arm received individualised dietary counselling adapted to each persons diet history and CVD risk profile. Counselling was given to the intervention group and their spouses at the start, and to participants thereafter at 3 and 9 months. Participants in the control group were told not to change their lifestyle during the trial with the exception of smoking. Participants in the control group were told that after the 1 year intervention period they would be offered dietary advice and supervised exercise training. The follow-up period was 1 year.


OutcomesTotal cholesterol, LDL and HDL cholesterol, triglycerides, SBP, DBP, % energy from fat.


NotesSubstudy of the Oslo Diet and Exercise Study. Data from the diet only arm were used. The authors kindly provided data on lipid levels and blood pressure presented in figure form in the paper.


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskA retrospective analysis of men in the Oslo Diet and Exercise Study (ODES) with the metabolic syndrome. In this trial a pre-randomised sequence of 4 possible intervention groups was prepared using simple randomisation without blocking.

Allocation concealment (selection bias)Unclear riskNo details.

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskParticipants in the control group were told that after 1 year they would be offered dietary advice and supervised physical training so they were not blinded. However, it is extremely difficult to blind participants to behavioural interventions so we have not classified this as at high risk of bias.

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskNo details.

Incomplete outcome data (attrition bias)
All outcomes
Low riskNo losses to follow-up were recorded.

Selective reporting (reporting bias)Unclear riskAll expected outcomes reported.

Other biasUnclear riskInsufficient information to judge.

Baron men 1990

MethodsRCT of parallel group design.


ParticipantsHealthy individuals recruited from GP lists in Abingdon, Oxfordshire. 437 subjects randomised, 51% men with mean age 41.9 years. Men and women have been analysed separately.


InterventionsIntervention administered by practice nurse. Individual or group session lasting 30 minutes on dietary advice to decrease total fat intake to 30-35% of calories and increase dietary fibre. A booklet was also given to participants on basic ideas of diet, recipes and advice concerning local restaurants. There was a brief follow-up session at 1 and 3 months. The comparison group were told they were part of a nutrition survey but were offered no dietary advice. Follow up at 3 and 12 months (3 month data used as follow-up less than 80% at 12 months).


OutcomesTotal cholesterol, HDL and LDL cholesterol, dietary fibre.


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskSee Table 1

Allocation concealment (selection bias)Unclear riskSee Table 1

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskSee Table 1

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskSee Table 1

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskSee Table 1

Baron women 1990

MethodsRCT of parallel group design.


ParticipantsHealthy individuals recruited from GP lists in Abingdon, Oxfordshire. 437 subjects randomised, 49% women with mean age 41.5 years. Men and women have been analysed separately.


InterventionsSee Baron 1990 for details of intervention. Follow-up at 3 and 12 months (3 month data used as follow-up less than 80% at 12 months).


OutcomesTotal cholesterol, HDL and LDL cholesterol, dietary fibre.


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskSee Table 1

Allocation concealment (selection bias)Unclear riskSee Table 1

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskSee Table 1

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskSee Table 1

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskSee Table 1

Beckman 1995

MethodsRCT of parallel group design.


ParticipantsRecruited from a community screening programme in Oslo, Norway. Participants (all men) aged 40-56 years had uncomplicated and untreated mild to moderate hypertension so were at high risk of CVD. Participants were otherwise healthy normal ECG, normal renal function and no chronic drug treatment. 22% were smokers but none quit during the study.


InterventionsParticipants were instructed individually by a nutritionalist to lower salt intake. This included advice not to add salt at the table or during cooking, avoid processed foods and other foods high in salt and increase consumption of fruit and vegetables to increase potassium levels. Visits for blood pressure checks by the nutritionalist at 1 and 2 weeks, 3, 6 and 12 months so presumably some reinforcement. At 3 months advice was also given to reduce body weight in those with a BMI >27 and reduce saturated fat intake in those with cholesterol above the 50th percentile. To increase compliance, free unsalted bread, sausages, cheese and margarine were provided for the first 2 weeks of the intervention. The control group received no advice and came to the clinic for blood pressure checks. At 12 months everyone received the intervention. Follow-up at 12 months.


OutcomesUrinary sodium and potassium, total cholesterol, HDL cholesterol and triglycerides, mean BP (supine and standing).


Notes2 control groups, a blood pressure control group and time control group. The blood pressure control group was used in the analyses. Mean blood pressure both supine and standing was measured rather than SBP and DBP. These data were not incorporated in the meta-analyses but dealt with descriptively. The longest follow-up period is 18 months but after 12 months the control groups also received dietary advice so 12 month follow-up data is used.


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskNo details

Allocation concealment (selection bias)Unclear riskNo details

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskNo details

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskPossibly. In random order, subjects belonging to the intervention group and the control group were seen in the outpatient clinic by the nutritionist for BP measurement.

Incomplete outcome data (attrition bias)
All outcomes
Low riskNo details given, assume no losses to follow-up. Stated that ITT analysis was used.

Selective reporting (reporting bias)Unclear riskAll expected outcomes reported.

Other biasUnclear riskInsufficient information to judge.

Beresford 1997

MethodsCluster RCT. Physician practice was unit of randomisation. Analysis was at individual level, allowing for random effects of clinic and physician practice, with physician nested within clinic. The denominator used in this review is the physician.


Participants28 GP practices in 6 primary care clinics in the USA. Participants attending routine visits without major illness were recruited. 2111 participants, 32% men, 25.5% greater than 65 years.


InterventionsLow intensity dietary intervention to increase fibre and reduce fat intake. Self-help booklet developed by the authors based on behavioural change principles from social learning theory and a brief motivational message from the physician. The control group received no intervention. Follow-up at 12 months.


OutcomesTotal dietary fat (% Kcal).


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskSee Table 1

Allocation concealment (selection bias)Unclear riskSee Table 1

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskSee Table 1

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskSee Table 1

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskSee Table 1

Beresford 2006

MethodsCluster RCT. Worksite was the unit of randomisation. Blocking criteria included baseline survey response rates, type and size of worksite and % of female employees. Analysis was at the level of the cluster.


Participants28 worksites (educational, medical and other) were randomised. All worksites with food serving cafeterias and with between 250 and 2000 employees within the greater metropolitan area of Seattle, USA were eligible.


InterventionsThe Special Intervention developed around the stages of change model addressing both the work environment and individual behaviour change. Each worksite had an employee advisory board (EAB) using a protocol specifying minimum activities required at each worksite and general structure for organising and implementing the intervention activities. The EAB met with a member of the research group approximately every 2 weeks, who provided materials, assisted with activities and participated in EAB meetings. The EABs took responsibility for tailoring the intervention. Intervention messages included increasing awareness about 5 a day and introducing the idea of eating more F&V in the workplace. The intervention targeted transition points from precontemplation to contemplation, contemplation to preparation, preparation to action and action to maintainance. The control group received a minimal intervention which encouraged eating more F&V using posters and brochures, newsletters, food demonstrations and a self help manual. Follow-up was at 24 months.


OutcomesFruit and vegetable servings/day.


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskSee Table 1

Allocation concealment (selection bias)Unclear riskSee Table 1

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskSee Table 1

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskSee Table 1

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskSee Table 1

Bloemberg 1991

MethodsRCT of parallel group design.


ParticipantsHigh risk - total cholesterol 6.5-10.0 mmol/L. 80 Dutch men randomised, mean age 47 years.


InterventionsIndividualised dietary advice from a dietitian with the aim to lower plasma cholesterol by 1mmol/L. After one week, advice reinforced by 2 follow-up calls. Information on healthy diet also mailed to participants on 5 occasions. Intervention lasted 6 months. No details regarding the comparison group. Follow-up at 6 months.


OutcomesTotal dietary fat and saturated fat (% Kcal), total cholesterol.


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskSee Table 1

Allocation concealment (selection bias)Unclear riskSee Table 1

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskSee Table 1

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskSee Table 1

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskSee Table 1

Bowen 2009

MethodsCluster RCT where religious organisations in Seattle were the unit of randomisation. Called the Eating for a Healthy Life project.


ParticipantsMembers of religious organisations (cluster RCT where 40 religious organisations were randomised - 2175 individuals). 100 households were drawn at random from each religious organisation (RO) list and further samples as required to complete the cohort. Individuals had to be active members of the RO, at least 18 years, English speakers, resident in the area for the next 12 months, had phone number and address, and had agreed to be contacted for follow-up. The sample size calculation of 20 pairs of ROs assumed an intra-class correlation of 0.015 for the primary outcome fruit and fibre questionnaire based on previous data. Data is analysed at the level of the individual using regression analyses which allowed for adjustment of random RO-level variation in addition to variation from individual respondents. The denominator used in this review is the RO.The mean age of the participants was 54 (15.9) years (range 18-100) with approximately equal numbers in the 30-50 year and 50-79 year age groups. 86% of the participants were female.


InterventionsIntervention package of self-help books and motivational messages and social interactions designed to change dietary behaviours (lowering fat and increasing F&V consumption). Materials were based on social learning theory and trans-theoretical models of behavioural change. The dietary intervention package was implemented for 9 months in each intervention RO. A healthy eating coordinator was assigned to each RO to help deliver the intervention. Intervention components included a volunteer advisory board, interpersonal support, dietary change mailings, social activities, healthy eating sessions and print advertisements. The spacing out of individual components was determined by the advisory boards for each RO appropriate for each RO climate. The intervention was targeted at the primary food preparer in each household, but all intervention components were made available to the entire RO membership. The intervention period was 9 months with follow-up at 12 months. The control ROs received the intervention after 12 months.


OutcomesPrimary outcomes were fat and F&V related behaviours using the Fat and Fibre Behaviour (FFB) Questionnaire. In 30% of the sample fat % energy intake, fruit and vegetable servings/day and dietary fibre (g/1000Kcal) were measured.


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskStratified randomisation of religious organisations by denomination, size, baseline response rate, percentage of families and education level.

Allocation concealment (selection bias)Unclear riskNo details

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskNo details. Cluster randomisation avoids contamination.

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskNo details

Incomplete outcome data (attrition bias)
All outcomes
Low riskLosses to follow-up were similar for each group (9.4% of the intervention group and 11% of the control group were lost to follow-up at 12 months).

Selective reporting (reporting bias)Unclear riskAll expected outcomes reported.

Other biasUnclear riskInsufficient information to judge.

Brekke 2005

MethodsRCT of parallel group design.


ParticipantsNon-diabetic first degree relatives of type-2 diabetic patients aged 25-55 with a medical history free of CHD recruited from outpatients clinics from questionnaires concerning family history of diabetes and advertisements in newspapers in the Goteborg area, Sweden. Exclusion criteria were diabetes (fasting blood glucose >6.1 mmol/L or 2 hour blood glucose >11.1 mmol/L or both), BMI>35, diseases or medications affecting glucose or lipid metabolism. 77 participants randomised, 60% men, mean age 43 years.


InterventionsTwo intervention arms - diet and diet plus exercise and control group. This review is concerned only with the diet intervention. Dietary advice aimed to decrease saturated fat (goal 10% of energy), increase monosaturated fat (goal 10-15% of energy) and n-3 fatty acids (goal 1% energy) from fatty fish and vegetable origin and for vegetables to take up one third of the lunch or dinner plate, increasing fruit and soluble fibre consumption as much as possible and increasing the intake of low GI foods. Dietician performed group counselling (3-11 participants/group with members of household who prepare food), sessions lasted 1-2 hours. There were 2 dietary education sessions 1-2 weeks apart at the beginning of the study. During the 16 week intervention period there was intensive follow-up with unannounced phone calls every 10 days (8 calls per person). Control group participants received a letter informing them to continue with their usual lifestyle. Follow-up was at 2 years. For ethical reasons after 1 year the control group began the intervention and were followed for a further 2 years. This review uses the follow-up data at 12 months.


OutcomesPlasma total cholesterol, LDL and HDL cholesterol and triglycerides (mmol/L), total fat %Kcal and saturated fat %Kcal, dietary fibre (g/1000Kcal - converted to g/day by assuming Kcal intake of 2000).


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskSee Table 1

Allocation concealment (selection bias)Unclear riskSee Table 1

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskSee Table 1

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskSee Table 1

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskSee Table 1

Buller 1999

MethodsCluster RCT. Employee cliques (informal social networks) were paired on several factors including mean fruit and vegetable consumption at baseline, ethnicity, sex composition, and size. One clique of each pair was randomly assigned to the intervention. Clique was the unit of analysis.


Participants41 cluster pairs of cliques (informal social networks) of blue collar workers recruited from 10 public employers in Arizona. Clusters include 905 workers of low socioeconomic class, 75% men, mean age 42.1 years.


InterventionsPeer education intervention to increase fruit and vegetable consumption. One employee from each clique was recruited as a peer educator. In addition there was a 5-a-day program using worksite mail, cafeteria promotions and speakers. The comparison group received this 5-a-day program but no peer education intervention. Follow-up was at 6 months.


OutcomesFruit and vegetable servings per day.


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskSee Table 1

Allocation concealment (selection bias)Unclear riskSee Table 1

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskSee Table 1

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskSee Table 1

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskSee Table 1

Cheng 2004

MethodsRCT of parallel group design.


ParticipantsParticipants with hypercholesterolaemia recruited from an urban academic primary care practice in Philadelphia. Participants were either referred by phycians or referred themselves from posters in the practice. None of the participants were on lipid lowering medications and none had prior formal nutritional counselling. 208 participants randomised, 28.6% men, mean age 53.8 years (range 25-101).


InterventionsThe intervention used the Food for Heart Programme, a core component of which is the dietary risk assessment - a food frequency questionnare based on the 20 foods highest in saturated fat and cholesterol in the American diet. The dietary risk assessment has 4 categories (meats, side dishes/desserts/snacks, dairy/eggs, fats/oils) each of which formed the basis of a brief focused visit to the practice. The intervention was administed by a research assistant with no background in nutrition. Problem foods were identified and advice sheets with suggestions for more healthy substitutes were given as well as a cook book with low fat recipes. The control group received no intervention. Follow-up was at 4 months.


OutcomesPlasma total cholesterol, LDL and HDL cholesterol (mmol/L)


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskSee Table 1

Allocation concealment (selection bias)Unclear riskSee Table 1

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskSee Table 1

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskSee Table 1

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskSee Table 1

Coates WHT MP 1999

MethodsRCT of parallel group design.


ParticipantsPost-menopausal women from minority and low socioeconomic class populations consuming at least 35% of energy from fat. Women recruited from clinics in Georgia, Alabama and Florida. Women had no major chronic disease and were not on lipid-lowering medication. 2208 women randomised (60% to the intervention), mean age 60 years.


InterventionsIntervention to reduce fat intake to 20% energy or less. A nutritionalist assigned fat gram goals to each participant. Group sessions were held weekly for 6 weeks, fortnightly for 6 weeks, and monthly for 9 months and then quarterly. Sessions included nutritional information and behavioural change strategies. Elements of the program were enhanced or added to meet the needs of a diverse population. The comparison group received "dietary guidelines for Americans" but were not counselled. Intervention lasted for 2 years, with follow-up at 6, 12 and 18 months. Data abstracted for 6 months follow-up as thereafter follow-up was poor.


OutcomesTotal dietary fat and saturated fat (% Kcal), fruit servings per day, vegetable servings per day.


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskSee Table 1

Allocation concealment (selection bias)Unclear riskSee Table 1

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskSee Table 1

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskSee Table 1

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskSee Table 1

Cox 1996

MethodsRCT of parallel group design.


ParticipantsWomen with poor diet with high fat content from low income families in USA. 150 women randomised, mean age 29 years, 69% black.


InterventionsEducation series emphasising the prevention of cardiovascular disease and cancer by dietary and lifestyle changes. Encouraged to decrease total and saturated fat intake, decrease salt intake, and increase consumption of low fat milk products, fruit and vegetables, soluble fibre, complex carbohydrates, antioxidant nutrients, calcium and potassium. Comparison group were taught about money management but received no information on health or nutrition. Follow-up at 6 months.


OutcomesTotal dietary fat and saturated fat (% Kcal), fruit servings per day, vegetable servings per day.


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskSee Table 1

Allocation concealment (selection bias)Unclear riskSee Table 1

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskSee Table 1

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskSee Table 1

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskSee Table 1

Djuric combination

MethodsRCT of parallel group design. The control group N is halved to take account of the two intervention arms.


ParticipantsPremenopausal women with at least one first degree relative with breast cancer, and consuming >25% fat of total energy and < 5/day F&V. The study was based in the USA. Women were required to be in good general health with no expected changes lifestyle or the use of oral contraceptives. Women taking supplements were excluded. Women were recruited through community advertising for the Nutrition and Breast Health Study. 127 women were randomised to 3 intervention arms (high F&V, low fat and a combination of low fat and high F&V) and a control. Mean age was 37 years (range 21-50).


Interventions2x2 factorial trial design - 3 intervention arms, high F&V intake, low fat and a combination of high F&V and low fat. The low fat arm was excluded from our analyses due to high loss to follow-up (leaving 82 participants randomised). The other intervention arms received individualised counselling every 2 weeks initially by a trained dietician, then monthly, and monthly group meetings for the intervention period of 12 months. The goal for the high F&V arm was to increase F&V to 9 servings/day in a specified variety to increase carotenoid intake. The goal for the combination arm was to decrease fat to 15% total energy from fat and increase F&V to 9 servings/day. Monthly meetings provided additional education on a variety of topics consistent with their dietary assignment. The control group received no dietary counselling and were told they should continue their usual diet. They received a one page daily food guide pyramid as a guide for healthy eating but this was not discussed. Follow-up was at 12 months. Longer-term follow-up (2 years) was reported by the authors (Radakovich 2006) but loss to follow-up was greater than 20%.


OutcomesPlasma total cholesterol, LDL and HDL cholesterol and triglycerides (mg/dL converted to mmol/L). Plasma alpha and beta-carotene, lutein, lycopene, beta-cryptoxanthin, alpha and gamma-tocopherol and ascorbic acid (µg/mL converted to µmol/L). Dietary intake of beta-carotene, ascorbic acid and alpha and gamma-tocopherol (µg/1000kcal/day).


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskSee Table 1

Allocation concealment (selection bias)Unclear riskSee Table 1

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskSee Table 1

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskSee Table 1

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskSee Table 1

Djuric high F&V

MethodsRCT of parallel group design. The control group N is halved to take account of the two intervention arms.


ParticipantsPremenopausal women with at least one first degree relative with breast cancer, and consuming >25% fat of total energy and < 5/day F&V. The study was based in the USA. Women were required to be in good general health with no expected changes lifestyle or the use of oral contraceptives. Women taking supplements were excluded. Women were recruited through community advertising for the Nutrition and Breast Health Study. 127 women were randomised to 3 intervention arms (high F&V, low fat and a combination of low fat and high F&V) and a control. Mean age was 37 years (range 21-50).


Interventionssee Djuric combination for details.


OutcomesPlasma total cholesterol, LDL and HDL cholesterol and triglycerides (mg/dL converted to mmol/L). Plasma alpha and beta carotene, lutein, lycopene, beta-cryptoxanthin, alpha and gamma-tocopherol and ascorbic acid (µg/mL converted to µmol/L). Dietary intake of beta-carotene, ascorbic acid and alpha and gamma-tocopherol (µg/1000kcal/day).


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskSee Table 1

Allocation concealment (selection bias)Unclear riskSee Table 1

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskSee Table 1

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskSee Table 1

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskSee Table 1

Elder promotora

MethodsRCT of parallel group design. The control group N is halved to take account of the two intervention arms.


ParticipantsSpanish dominant latinas from central and southern regions of San Diego county. Women were recruited and assessed for eligibility using random digit dialing using a telephone list of Hispanic surname households. 357 women randomised, mean age 40 years.


InterventionsTwo intervention arms to decrease dietary fat and increase fibre - promotora and tailored. In the promotora arm participants received weekly visits or phone calls from promotoras (lay health advisors) over a 14 week period and 12 tailored newsletters with homework assignments mailed weekly. Promotoras worked with individuals to negotiate behaviour change and provide support and encouragement and the weekly newsletters were used to guide discussions. The tailored arm received the 12 weekly newsletters and homework assignments created by using baseline assessments for each individual. They provided feedback on assessments as well as personalised goal setting and dealing with identified barriers. The last newsletter contained information from the 12 week assessment and included changes achieved and steps to continue or maintain the change process. The control group received newsletters in Spanish covering the same content area, but they were off the shelf materials readily available to the public. Follow-up was at 12 months but data for this review were taken at 12 weeks due to the high loss to follow-up at 6 and 12 months.


OutcomesTotal dietary fat and saturated fat (grams, converted to % energy from fat by using Kcal intakes provided in the report). Only follow-up data were provided for these outcomes.


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskSee Table 1

Allocation concealment (selection bias)Unclear riskSee Table 1

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskSee Table 1

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskSee Table 1

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskSee Table 1

Elder tailored

MethodsRCT of parallel group design. The control group N is halved to take account of the two intervention arms.


ParticipantsSpanish dominant latinas from central and southern regions of San Diego county. Women were recruited and assessed for eligibility using random digit dialing using a telephone list of Hispanic surname households. 357 women randomised, mean age 40 years.


InterventionsSee Elder promotora for details.


OutcomesTotal dietary fat and saturated fat (grams, converted to % energy from fat by using Kcal intakes provided in the report). Only follow-up data were provided for these outcomes.


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskSee Table 1

Allocation concealment (selection bias)Unclear riskSee Table 1

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskSee Table 1

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskSee Table 1

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskSee Table 1

ENCORE

MethodsRCT of parallel group design.


ParticipantsParticipants were overweight or obese with untreated hypertension (SBP 130-159, DBP 85-99 mm Hg based on 4 screening visits) recruited from physician referrals, community screenings, mass media advertising in North Carolina, USA. 144 participants randomised (46 to DASH alone, 49 to control), the mean age was 52 years and 32.6% were men.


InterventionsThe DASH diet is high in low fat diary products and fruits and vegetables, rich in fibre and lower in fats. Participants in the intervention group received counselling on the DASH diet and provided feedback on their adherence in weekly group sessions. The goal of the sessions was to assist participants in learning how to buy and prepare appropriate foods, enhance their motivation to chose to eat these foods and to overcome any obstacles. A nutritionalist made the recommendations and small group sessions were held weekly (30-45 minutes each) at the research centre. Immediately after randomisation and before the counselling sessions participants entered a 2 week controlled isocalorific feeding period to improve compliance with the DASH diet. The comparison group were asked to maintain their usual dietary and exercise habits. Follow-up was at 4 months after the intervention period.


OutcomesTotal, HDL and LDL cholesterol, triglycerides, SBP, DBP, urinary sodium and potassium, dietary intake of fat, fibre, fruits and vegetables.


NotesTwo intervention groups - DASH alone and DASH plus weight management. The review looks at only at the DASH alone arm.


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Low riskRandomised in groups of 2-5 participants using a computer program.

Allocation concealment (selection bias)Low riskSealed envelopes used so allocation was concealed.

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskParticipants were provided their treatment group assignments in sealed envelopes which suggests they were unblinded. However, blinding of participants and personnel for behavioural interventions is difficult and often not possible so we have not judged this as at high risk of bias.

Blinding of outcome assessment (detection bias)
All outcomes
Low riskStaff members performing the assessments were unaware of group assignment.

Incomplete outcome data (attrition bias)
All outcomes
Low riskOnly one participant lost to follow-up and ITT analysis used.

Selective reporting (reporting bias)Low riskAll expected outcomes reported.

Other biasUnclear riskInsufficient information to judge.

Fuemmeler 2006

MethodsCluster RCT. Churches were paired according to size and socioeconomic status of congregants and urban or rural geography and then each pair was randomised to intervention or control. Churches were the unit of analysis.


Participants14 black American churches with at least 200 congregants located near cancer society offices in California, Georgia, North and South Carolina, Delaware and Virginia, USA. Clusters contained 1020 individuals, 26.6% men, mean age 49.7 years.


InterventionsThe Body and Soul intervention designed to increase F&V consumption included a set of core church wide activities (e.g. serving F&V after church services, food demonstrations and taster tests, invited speakers, messages in pastors sermons), self help materials (cook book and video containing spiritual and secular motivational messages targeting F&V intake) and peer counselling based on the principles and techniques of motivational interviewing. Congregations nominated members to be part of an oversight committee responsible for implementing the Body and Soul intervention. The committee liased with the research team and members of the committee and peer counsellors were given training. The control group received the delayed intervention at 6 months. Follow-up was at 6 months.


OutcomesF&V (servings/day).


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Allocation concealment (selection bias)Unclear riskB - Unclear

Gann 2003

MethodsRCT of parallel group design.


ParticipantsHealthy women aged 20-40 years recruited by direct mailings and advertising in downtown Chicago. Women who were on diets, were pregnant or planning pregnancy and those on oral contraceptives were excluded. 213 women randomised, mean age 33 years.


InterventionsLow fat high fibre dietary intervention. Goals were to reduce total fat intake to <20%, increase total fibre intake to 25-30g, increase F&V intake to >8 servings/day, to eat more complex carbohydrates (carbohydrate intake 60-65% Kcal/day) and protein intake 15-20% Kcal/day. Women were not encouraged to reduce calorie intake. Intervention included classroom nutrition education (18 group classes) plus individual counselling (2 individual meetings in 12 months) to provide women with the knowledge and behavioural skills necessary to make a permanent lifestyle change. To maximise the impact of the intervention sessions, appropriate food was prepared and served. Sessions included practice shopping, label reading, meal preparation techniques and eating out and convienience foods were discussed. The control group were told to follow their usual diet and received a leaflet on healthy eating. After 12 month intervention period they received some of the materials given to the intervention group. Follow-up was at 12 months.


OutcomesTotal fat %Kcal, saturated fat (g - converted to %Kcal by using Kcal intake as reported), total dietary fibre (g/day).


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskSee Table 1

Allocation concealment (selection bias)Unclear riskSee Table 1

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskSee Table 1

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskSee Table 1

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskSee Table 1

Havas 1998

MethodsCluster RCT of cross-over design. Sites were switched 4 months after completion of phase 1. Each site acted as own control, using intention to treat analysis. Phase 1 participants were not eligible to enrol in phase 2. Specially employed peer educators conducted the intervention.


ParticipantsWomen on low incomes recruited from a government funded special supplemental nutrition program for women infants and children in Baltimore City. 16 sites where this program was carried out were randomised, involving 3122 women, of whom 40.5% were aged between 18-24, 26.5% between 25-29 and 33% 30 years or more.


InterventionsFive a day promotional program where the goal was to increase fruit and vegetable consumption by at least half a serving per day. Peer educators delivered 2 types of nutrition education - brief messages regarding increasing fruit and vegetable consumption at enrolment, and 3 group discussions of 45 minutes during the 6 month intervention period which included personal goal setting, overcoming perceived barriers and maintenance strategies. Printed materials, visual aids and booklets with recipes were distributed. Four individually tailored letters were sent over the 6 month period. Comparison group received no intervention. Follow-up at 8 months.


OutcomesFruit and vegetable servings per day.


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskSee Table 1

Allocation concealment (selection bias)Unclear riskSee Table 1

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskSee Table 1

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskSee Table 1

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskSee Table 1

Hellenius 1993

MethodsRCT of parallel group design.


ParticipantsModerate/high risk - total cholesterol 5.2-7.8 mmol/L, DBP less than or equal to 100 mm Hg, fasting triglycerides less than or equal to 5.6 mmol/L, fasting blood glucose less than or equal to 6.7 mmol/L, recruited from an ongoing prevention program in Sweden. 160 men randomised, mean age 46.2 years.


InterventionsThree interventions - dietary advice alone, exercise alone and diet plus exercise. This review is concerned only with the dietary intervention alone (40 men randomised). Physician provided individual verbal and written information about diet in accordance with consensus documents, and participants also met with a dietitian 2 weeks later for further advice concerning low fat diets. Compliance with the intervention was checked at 3 months. The comparison group were told to continue with their lifestyle as previously. Follow-up at 6 months.


OutcomesTotal dietary fat (% Kcal), total HDL and LDL cholesterol, triglycerides, SBP, DBP.


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskSee Table 1

Allocation concealment (selection bias)Unclear riskSee Table 1

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskSee Table 1

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskSee Table 1

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskSee Table 1

Henderson WHTV 1990

MethodsMulticentre RCT of parallel group design.


ParticipantsHigh risk - women recruited from clinical units in USA at increased risk of breast cancer (one or more of the following - female first or second degree relative with breast cancer, one or more benign breast biopsies, first birth after the age of 30 or nulliparous, or history of breast biopsy with atypical epithelial hyperplasia. 303 women randomised, mean age 54.8 years.


InterventionsIntervention to decrease fat intake to 20% of total calories and increase complex carbohydrate intake to ensure adequate levels of vitamins and minerals. Nutritionalist led group sessions providing information and behavioural skills to make lifestyle changes. Group sessions once a week for 8 weeks, twice a month for the next 6 months and then monthly for 12 months. Individual sessions at 2 and 12 weeks. No details regarding the comparison group. Follow-up at 2 years.


OutcomesTotal dietary fat (% Kcal).


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskSee Table 1

Allocation concealment (selection bias)Unclear riskSee Table 1

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskSee Table 1

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskSee Table 1

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskSee Table 1

John 2002

MethodsRCT of parallel group design.


ParticipantsParticipants recruited from primary health care centres in Oxfordshire, UK. Participants aged between 25 and 64 years with no chronic diseases were eligible. Those who were pregnant or attempting to conceive or on dietary supplements were excluded. 729 participants randomised, 49% men, mean age 46 (SD 10.1) years.


InterventionsBrief negotiation method to increase F&V consumption to at least 5 portions/day. A trained research nurse discussed the benefits of eating more F&V and presented a pictorial portion guide. The brief negotiation method was used to encourage participants to identify specific and practical ways consistent with their habits and preferences of eating more F&V. Participants attended the health centre for 2 appointments 6 months apart and were phoned 2 weeks after the first appointment to reinforce the message and discuss any problems. At 3 months participants were sent a letter reinforcing the 5 a day message and a booklet with seasonal recipes and strategy check list of ways to increase additional portions of F&V. Participants were given a copy of their individualised action plan, a fridge magnet with the 5 a day logo, a portion guide and a 2 week self monitoring record book. The control group were asked to continue their usual diet and received the intervention after 6 months. Follow-up was at 6 months.


OutcomesSBP and DBP (mm Hg), plasma total cholesterol (mmol/L), plasma alpha and beta-carotene, lutein, lycopene, beta-cryptoxanthin, alpha and gamma-tocopherol and ascorbic acid (all µmols/L) and F&V (servings/day).


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskSee Table 1

Allocation concealment (selection bias)Unclear riskSee Table 1

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskSee Table 1

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskSee Table 1

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskSee Table 1

Keyserling 1997

MethodsCluster RCT. Data were analysed at the level of the individual, allowing for the effect of physician clusters. The denominator used in this review is the physician.


Participants42 primary care physicians from 21 community and rural health centres in North Carolina and Virginia were randomised. High risk patients with elevated LDL cholesterol (greater than 4.1 mmol/L or between 3.4 -4.1 mmol/L plus 2 more risk factors or known CHD) were identified during routine appointments. The number of participants was 372, 67% were female, mean age 56 years.


InterventionsFood for heart program dietary intervention administered by physicians. All underwent a 90 minute training session. The intervention included a brief dietary assessment and three 5-10 minute dietary counselling sessions including referral to a dietitian if LDL remained elevated at 4 months, and a prompt to consider lipid lowering drugs at 7 months if LDL remained elevated still. The comparison group was usual care. Follow-up was at 4, 7 and 12 months. Four month data were abstracted as greater than 10% of participants were taking lipid lowering medication after this time.


OutcomesTotal cholesterol and LDL cholesterol.


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskSee Table 1

Allocation concealment (selection bias)Unclear riskSee Table 1

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskSee Table 1

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskSee Table 1

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskSee Table 1

Koopman 1990

MethodsRCT of parallel group design.


ParticipantsHigh risk - mild to moderate hypertension (DBP 90-110 mm Hg on 3 separate occasions). Participants recruited from a Dutch GP surgery - 35 randomised, 46% men, mean age 45 years.


InterventionsPilot intervention of intensive dietary counselling by a dietitian in general practice. Participants visited 3 times and goals were to have a daily intake of 80-100 mmol sodium, 30 g of fibre, 10-12% of polyunsaturated fatty acids. Comparison group told they would see the dietitian in 3 months. Follow-up at 3 months.


OutcomesSBP, DBP, urinary sodium.


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskSee Table 1

Allocation concealment (selection bias)Unclear riskSee Table 1

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskSee Table 1

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskSee Table 1

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskSee Table 1

Kristal 2000

MethodsRCT of parallel group design, individual randomisation stratified by age and sex.


ParticipantsParticipants were selected at random from enrollees from an American health maintenance organisation. 1459 subjects randomised, 50% men, mean age 45.8 years.


InterventionsSelf-help manual of dietary change based on social learning theory designed to promote lower fat and higher fruit and vegetable consumption. Manual included dietary information, dietary analysis with behavioural feedback. Subjects also received a motivational phone call by a trained health educator and newsletters. No details regarding the control group. Follow-up at 12 months.


OutcomesFruit and vegetable servings per day.


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskSee Table 1

Allocation concealment (selection bias)Unclear riskSee Table 1

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskSee Table 1

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskSee Table 1

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskSee Table 1

Lanza men 2001

MethodsSee Schatzkin 2000 for details.


ParticipantsSee Schatzkin 2000 for details. Data in this publication are analysed separately for men and women.


InterventionsSee Schatzkin 2000 for details.


OutcomesUnlike Schatzkin 2000, data are reported separately for men and women. Additional outcomes reported in this publication are fruit (g/day), vegetables (g/day) and dietary intake of vitamin C (mg/day), vitamin E (mg/day) and total carotenoids (µg/day).


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskSee Table 1

Allocation concealment (selection bias)Unclear riskSee Table 1

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskSee Table 1

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskSee Table 1

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskSee Table 1

Lanza women 2001

MethodsSee Schatzkin 2000 for details.


ParticipantsSee Schatzkin 2000 for details. Data in this publication are analysed separately for men and women.


InterventionsSee Schatzkin 2000 for details.


OutcomesUnlike Schatzkin 2000, data are reported separately for men and women. Additional outcomes reported in this publication are fruit (g/day), vegetables (g/day) and dietary intake of vitamin C (mg/day), vitamin E (mg/day) and total carotenoids (µg/day).


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskSee Table 1

Allocation concealment (selection bias)Unclear riskSee Table 1

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskSee Table 1

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskSee Table 1

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskSee Table 1

Little 2004

MethodsRCT of parallel group design (2x2x2 factorial trial).


ParticipantsParticipants were recruited during the "watchful waiting" period for hypertension from 6 clinics in Southampton, UK. Inclusion criteria were one BP reading of >160/90 and not on antihypertensive treatment. Exclusion criteria were established hypertension and participants who were very ill or less able to change diet. 33 participants randomised to the prompts plus low salt intervention, 37 to the control (no intervention). Mean age was 55 (10) years, 56% were male.


Interventions2x2x2 factorial design: no booklet or booklet, no advice to use low salt or advice to use low salt, no use of prompts or use of healthy lifestyle prompts. We excluded the booklet intervention as it was multifactorial (advice to reduce smoking, alcohol and weight as appropriate and exercise regularly). We also excluded the healthy lifestle prompts alone as loss to follow-up was >20% for this intervention. Our analysis focused on the prompts plus low salt intervention with no intervention as the comparison group. Participants were given a pot of low sodium salt and asked to use it in cooking and on food in place of normal salt. The healthy lifestyle prompts included a fatty food swap sheet where participants were asked to swap foods listed in one column with lower fat foods from the other column. Participants were asked to take the sheet with them when shopping and place it in a prominent postion at home such as the fridge door. Fruit, vegetable and fibre daily prompt sheets gave options to increase consumption of these. The intervention(s) were administered by research nurses in GP surgeries. Interventions were reinforced at 4 weeks and 6 months. Control participants received no intervention. Follow-up was at 6 months.


OutcomesSBP and DBP (mm Hg), Total cholesterol, LDL cholesterol and HDL cholesterol (mmol/L), total plasma carotenoids (mmol/L - converted to µmol/L) and % energy from fat.


NotesF&V (g/day) were also measured in this trial, but we were unable to verify the data with the authors and have therefore excluded this outcome.


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskSee Table 1

Allocation concealment (selection bias)Unclear riskSee Table 1

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskSee Table 1

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskSee Table 1

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskSee Table 1

Lutz non-tailored

MethodsRCT of parallel group design. The control group N is divided by 3 to take account of the 3 intervention arms.


ParticipantsHealthy adults recruited from subscribers to an American health maintenance organisation. 710 participants randomised, 35.6% men, mean age 39.3 years.


InterventionsThree interventions to increase fruit and vegetable consumption. The 3 interventions were non-tailored newsletters, computer tailored newsletters taking into consideration individual baseline survey dietary information, and tailored newsletters with goal setting - to increase fruit and vegetable consumption to 5 or more servings per day. The control group did not receive a newsletter. Newsletters were posted each month for 4 months to participants in the intervention groups. Follow-up was at 6 months.


OutcomesFruit and vegetable servings per day.


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskSee Table 1

Allocation concealment (selection bias)Unclear riskSee Table 1

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskSee Table 1

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskSee Table 1

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskSee Table 1

Lutz tailored&goals

MethodsRCT of parallel group design. The control group N is divided by 3 to take account of the 3 intervention arms.


ParticipantsHealthy adults recruited from subscribers to a health maintenance organisation. 710 participants randomised, 35.6% men, mean age 39.3 years.


InterventionsSee 'Lutz non-tailored' for details of intervention. Follow-up was at 6 months.


OutcomesFruit and vegetable servings per day.


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskSee Table 1

Allocation concealment (selection bias)Unclear riskSee Table 1

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskSee Table 1

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskSee Table 1

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskSee Table 1

Lutz tailored 1999

MethodsRCT of parallel group design. The control group N is divided by 3 to take account of the 3 intervention arms.


ParticipantsHealthy adults recruited from subscribers to a health maintenance organisation. 710 participants randomised, 35.6% men, mean age 39.3 years.


InterventionsSee 'Lutz non-tailored' for details of intervention. Follow-up was at 6 months.


OutcomesFruit and vegetable servings per day.


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskSee Table 1

Allocation concealment (selection bias)Unclear riskSee Table 1

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskSee Table 1

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskSee Table 1

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskSee Table 1

Maskarinec 1999

MethodsRCT of parallel group design.


ParticipantsHigh risk - at increased risk of breast cancer (greater than 50% mammographic densities) and less than 5-a-day. 33 women randomised, mean age 48.9 years, mostly of Asian decent. Based in Hawaii.


InterventionsIndividualised dietary counselling program with dietitian - goal to incorporate 9 servings of fruit and vegetables in daily diet. Group meetings monthly for 6 months for cooking instructions and demonstrations. Participants logged their daily intake of fruit and vegetables. The comparison group received nutritional counselling on how to maintain a healthy diet. Follow-up at 6 months.


OutcomesTotal dietary fat (%Kcal), total cholesterol, fruit and vegetable servings per day, beta-carotene.


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskSee Table 1

Allocation concealment (selection bias)Unclear riskSee Table 1

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskSee Table 1

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskSee Table 1

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskSee Table 1

Moy 2001

MethodsRCT of parallel group design. Randomisation was by family.


ParticipantsHealthy 30-59 year old brothers and sisters of patients with documented CHD diagnosed before the age of 60. Siblings with at least one of the following risk factors were eligible: LDL cholesterol ≥3.4 mmol/L, BP ≥140/90 mm Hg or current use of antihypertensives or current smoking. 235 individuals were randomised, 52% men, mean age 46 (SD 7) years. This study was based in the USA.


InterventionsIntervention focused primarily on decreasing total fat consumption and daily monitoring. Nurse counselling followed the National Cholesterol Education Programme Adult Treatment Panel II Guidelines which recommend dietary intervention as the first line approach in the treatment of hypercholesterolaemia. Participants were seen individually and with family members every 6-8 weeks by trained nurse counsellors (approximately 40 hours training by PI and dietician). Participants were given a "fat allowance" based on intake at baseline, current lifestyle and willingness to change. Participants were taught how to read food labels and use a fat counter to monitor and record total daily fat intake and negotiated their fat intake up or down with the nurse in counselling sessions. Physicians of siblings in the intervention group were asked explicitly not to manage dietary interventions. Participants in the usual care group were referred to physicians for dietary management. Physicians received specific detailed recommendations for risk factor management at baseline, 1 year and 2 years. Follow-up was at 2 years.


OutcomesPlasma total cholesterol, LDL and HDL cholesterol and triglycerides (mmol/L), %Kcal from total fat and % Kcal from saturated fat.


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskSee Table 1

Allocation concealment (selection bias)Unclear riskSee Table 1

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskSee Table 1

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskSee Table 1

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskSee Table 1

Neil dietitian1995

MethodsRCT of parallel group design. The control group N is halved to take account of the two intervention arms.


ParticipantsHigh risk - total cholesterol 6 - 8.5 mmol/L on repeat screening at a general practice in Oxfordshire. 309 subjects randomised, 53% men, median age 55 years.


InterventionsThree interventions all containing advice to decrease total daily fat consumption to 30% or less. Participants were either randomised to receive advice from a dietitian or a nurse or to receive a leaflet containing dietary information by post. Those randomised to see the dietitian received an individual appointment of 30 minutes to discuss dietary habits and weight and offer advice to decrease fat consumption. At 8 weeks participants had a further 10 minute appointment. Those randomised to see the nurse also had an individual 30 minute appointment using a structure food frequency questionnaire and offered similar advice to the dietitian with a further 10 minute appointment at 8 weeks. The comparison group to these 2 interventions was the leaflet. Follow-up was at 6 months.


OutcomesTotal cholesterol, HDL and LDL cholesterol.


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskSee Table 1

Allocation concealment (selection bias)Unclear riskSee Table 1

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskSee Table 1

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskSee Table 1

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskSee Table 1

Neil nurse 1995

MethodsRCT of parallel group design. The control group N is halved to take account of the two intervention arms.


ParticipantsHigh risk - total cholesterol 6 - 8.5 mmol/L on repeat screening at a general practice in Oxfordshire. 309 subjects randomised, 53% men, median age 55 years.


InterventionsSee 'Neil 1995 dietitian' for details of intervention. Follow-up was at 6 months.


OutcomesTotal cholesterol, HDL and LDL cholesterol.


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskSee Table 1

Allocation concealment (selection bias)Unclear riskSee Table 1

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskSee Table 1

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskSee Table 1

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskSee Table 1

Riddell 2000

MethodsRCT of parallel group design, individual randomisation stratified by sex.


ParticipantsHigh risk - men and women with elevated plasma total homocysteine (greater than or equal to 9 micromol/L). Sixty six subjects randomised aged 36-71 years (61% men) recruited from advertisements in local newspapers. Fifteen subjects were randomised to the intervention of interest to this review - increasing the consumption of folate rich foods, and 15 to the control group. Based in New Zealand.


InterventionsThree interventions for decreasing homocysteine levels by increasing intake of folic acid - the first was supplementation, the second was consumption of fortified breakfast cereals and the third was increased consumption of folate rich foods. This review is concerned only with the third intervention. Subjects were asked to increase their intake of folate rich foods to 600 micrograms per day. Subjects were provided with a list of folate rich foods and were given detailed dietary information by a dietitian at recruitment and randomisation and reinforced advice by fortnightly phone calls. Additional encouragement was given by phone when required. The control group continued to follow a fat modified diet which was also used as a run in before randomisation in the intervention groups. The intervention lasted for 12 weeks and follow-up was 12 weeks.


OutcomesRed cell folate, serum folate, total homocysteine, dietary folate and dietary fibre.


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskSee Table 1

Allocation concealment (selection bias)Unclear riskSee Table 1

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskSee Table 1

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskSee Table 1

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskSee Table 1

Rock 2001

MethodsRCT of parallel group design.


ParticipantsPremenopausal women with cervical intraepithelial neoplasia (a precancerous condition) recruited from primary care and gynecology medical practices in the USA. Women who were pregnant, lactating, were post menopausal, had a previous history of cancer or a current diagnosis of any malignancies were excluded. 56 women were randomised with a mean age of 27.8 (SD 6) years.


InterventionsAim was to increase F&V consumption to 8-10 servings/day. Specific strategies and food choices were identified and targeted through individualised counselling and guidance utilising a self management approach based on social cognitive behavioural theories. A dietician administered the intervention where counselling was by phone or internet with a minimum of weekly contact or more frequent if problems arose. The counselling protocol was supplemented by monthly newsletters and incentives to promote retention. The control group were provided with newsletters and incentives of a more general nature without specific nutrition information or dietray guidance. Follow-up was at 12 months but data are presented only for 6 months follow-up.


OutcomesPlasma alpha and beta-carotene, beta-cryptoxanthin, leutin, lycopene and total carotenoids (micrmol/L). F&V servings/day.


NotesTable 1 in the paper provides dietary intake of micronutrients also but these are expressed only as medians and ranges. Contact authors to see if these data are available as means and SDs - for a future update.


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskSee Table 1

Allocation concealment (selection bias)Unclear riskSee Table 1

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskSee Table 1

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskSee Table 1

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskSee Table 1

Sacerdote 2006

MethodsRCT of parallel group design.


ParticipantsHealthy 18-65 year olds recruited from GP clinics in Italy. Inclusion criteria were BMI<30 and no chronic or severe diseases. Those visiting the GP for GI complaint or with dietary restrictions were excluded. 3179 participants randomised (1592 intervention, 1587 control), mean age 44.5 (12.4) years, 50% male.


InterventionsPersonalised nutritional education intervention administered by a GP using a brochure based on Italian guidelines for correct nutrition, 1998. Intervention focused on the importance of increasing consumption of F&V (goal >5/day), fish (goal >1/week) and olive oil (goal - use in place of other fats) and decreasing meat (goal <3/week), snacks and sweets. Participants randomised to the intervention visited the GP surgery 3 times over the 12 month intervention period - interviews lasted 15 minutes each. Control participants recieved a "sham" intervention where they met the GP for a simpler non-personalised conversation without the use of the brochure. Each GP took part in a 4 day training course on nutrition carried out by clinical nutritionalists. Follow-up was at 12 months.


OutcomesSBP and DBP (mm Hg) and fruit and vegetable servings/week (converted to servings/day).


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskSee Table 1

Allocation concealment (selection bias)Unclear riskSee Table 1

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskSee Table 1

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskSee Table 1

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskSee Table 1

Schatzkin 2000

MethodsRCT of parallel group design.


ParticipantsHigh risk - one or more colorectal adenomas removed within 6 months before recruitment. Referrals from endoscopists. 2079 randomised, 64.5% men, mean age 61 years. American multicentre study.


InterventionsIntensive counselling to follow a low fat (less than 20% calories), high fibre (18 g/1000 cals) diet and to increase fruit and vegetable consumption to 3.5 servings /1000 cals. Nutritional information and behavioural modification techniques. More than 50 hours counselling sessions over 4 years. Comparison group were given a standard brochure on healthy eating. Follow-up at 4 years.


OutcomesTotal dietary fat (% Kcals), dietary fibre, fruit and vegetable servings per day.


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskSee Table 1

Allocation concealment (selection bias)Unclear riskSee Table 1

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskSee Table 1

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskSee Table 1

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskSee Table 1

Silman 1983

MethodsRCT of parallel group design.


ParticipantsParticipants had persistent untreated hypertension for at least 13 months prior to the trial where DBP was between 95 and 104 mm Hg. Participants between the age of 50-64 years were recruited from 2 GP surgeries in East London, 28 were randomised, 12 to the intervention and 16 to the control group.


InterventionsThe intervention group received general health education plus specific advice to reduce salt intake. The diet was developed to produce a daily intake of 100mMol sodium which had been previously tested on a group of laundry workers in East London. The aim was to produce a diet appropriate to the population of East London with specific advice given on sandwich fillings and other foods consumed during working hours. Advice was given at GP surgeries. General health education advice included quitting smoking, reducing stress and the need for regular exercise. The comparison group received general health education only. Follow up was at 1,2,3,6 and 12 months.


OutcomesSBP, DBP


NotesThe study also examined the effects of the intervention on urinary sodium and potassium but the loss to follow-up was too high for these outcomes and so the data is not used.


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskNo details

Allocation concealment (selection bias)Unclear riskNo details

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskNo details

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskNo details

Incomplete outcome data (attrition bias)
All outcomes
Unclear risk16.6% in the intervention group and 6.3% in the control group were lost to follow-up for the outcome BP over 12 months. The authors state that there were different non-attenders at the various visits so they checked baseline values for attenders and non-attenders at each visit.

Selective reporting (reporting bias)Unclear riskAll expected outcomes reported.

Other biasUnclear riskInsufficient information to judge.

Smith-Warner 2000

MethodsRCT of parallel group design, individual randomisation stratified by sex.


ParticipantsHigh risk - men and women with recent history (previous 5 years) of colorectal adenomas recruited from a gastroenterology clinic in Minnesota. 201 participants randomised, 71% men, mean age 59.3 years.


InterventionsParticipants were asked to increase fruit and vegetable consumption to at least 8 servings per day. Clinic visits at 3, 6, 9 and 12 months to reinforce this plus 4 additional individual diet intervention appointments. Intervention used behaviour modification strategies derived from social learning theory and nutritional counselling focused on goal setting. The control group continued their usual diet and were seen at 3, 6, 9 and 12 month clinic visits. Follow-up at 12 months.


OutcomesFruit and vegetable servings per day.


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskSee Table 1

Allocation concealment (selection bias)Unclear riskSee Table 1

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskSee Table 1

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskSee Table 1

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskSee Table 1

Sorensen work+family

MethodsCluster RCT. Data were analysed at the level of the individual, allowing for clustering within worksites. The denominator used in this review is the worksite. The control group N is halved to take account of the two intervention arms.


Participants22 worksites in USA randomised including 1359 employees at community health centres. 84% women, participants described as healthy and from racially and ethnically diverse backgrounds. No details regarding age.


InterventionsTwo interventions to increase fruit and vegetable consumption - one based at the worksite only, where workers participated in program planning whose aims were to change individual behaviour and make changes in the worksite environment. The other intervention included the worksite intervention plus a family intervention involving a written learn at home program, an annual newsletter, annual family festival and periodic mailings. The comparison group received a minimal intervention comprising exposure to national media campaigns and a 1 hour general nutrition presentation. This minimal intervention was received also by both intervention groups. Follow-up was at 19.5 months.


OutcomesFruit and vegetable servings per day.


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskSee Table 1

Allocation concealment (selection bias)Unclear riskSee Table 1

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskSee Table 1

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskSee Table 1

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskSee Table 1

Sorensen worksite

MethodsCluster RCT. Data were analysed at the level of the individual, allowing for clustering within worksites. The denominator used in this review is the worksite. The control group N is halved to take account of the two intervention arms.


Participants22 worksites in USA randomised including 1359 employees at community health centres. 84% women, participants described as healthy and from racially and ethnically diverse backgrounds. No details regarding age.


InterventionsSee ''Sorensen work+family' for details of intervention. Follow-up was at 19.5 months.


OutcomesFruit and vegetable servings per day.


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskSee Table 1

Allocation concealment (selection bias)Unclear riskSee Table 1

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskSee Table 1

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskSee Table 1

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskSee Table 1

Stevens 2003

MethodsRCT of parallel group design.


ParticipantsHealthy women - members of a HMO in Oregon, USA. Women aged 40-70 (mean 53.8) years who had a negative result on a recent screening mammogram. Women were only included if their total cholesterol level was 5.2mmol/L or greater (authors chose the top half of the cholesterol distribution to increase the probability of detecting dietary change), and were willing to change dietary patterns and were willing to consider regular breast self-exam (control condition - recruitment emphasised cancer prevention and control). Women were excluded if they were taking statins or had treatment for cancer in the previous year. 616 women were randomised (308 intervention, 308 control).


InterventionsThe dietary intervention combined strategies from motivational interviewing, problem solving and social cognitive theory. Experienced masters degree level counsellors provided individual counselling based in a research clinic. The first individual counselling session (45 mins) focused on decreasing fat and increasing fruit and vegetables and wholegrains. Participants were provided feedback from a baseline questionnaire and asked to select one of two goals (decreasing fat or increasing fruit and vegetables). The second counselling session (45 mins) 2-3 weeks later focused on the goal participants had not chosen at the first session. Telephone support was given 2-3 weeks after the second session and again 2-3 weeks later (5-10 mins each). Participants randomised to the control arm received an intervention focused on breast self examination where individuals received one counselling session and 2 follow-up phone calls but no dietary recommendations. Follow-up was at 12 months.


OutcomesTotal cholesterol (mg/dL converted to mmol/L), % energy from fat and F&V (servings/day).


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskSee Table 1

Allocation concealment (selection bias)Unclear riskSee Table 1

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskSee Table 1

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskSee Table 1

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskSee Table 1

Takahashi 2006

MethodsRCT of cross-over design but data analysed and presented as a parallel group design at time of cross-over at 12 months.


ParticipantsParticipants from 2 rural villages in Japan recruited through public magazines and posters. Individuals were eligible if they were aged between 40 and 69 and had physician permission to participate if under medical treatment or dietary control. 550 participants randomised, 32% men, mean age 56 years. Of the participants in the control group at baseline, 9.6% had hypertension, 2.9% had diabetes and 9.6% had hyperlipidaemia.


InterventionsTailored dietary intervention to encourage a decrease in sodium intake and an increase in vitamin C and carotene intake via increasing F&V consumption. Dietary goals were to decrease salt to less than 8 and 10g/day in women and men respectively and increase carotene intake to more than 5000 µg/day and vitamin C intake to more than 200mg/day. The intervention consisted of 2 individualised dietary counselling sessions at baseline and 5 months (15 minutes each), a group lecture half-way through the intervention, and 2 newsletters. Control subjects recieved the intervention at 12 months (cross-over period). Follow-up data were presented at 12 months.


OutcomesSBP and DBP (mmHg), fruit and vegetable intake (g/day converted to servings/day using a typical 80g serving), dietary fibre (g/day), dietary intake of vitamin C (mg/day), alpha and beta-carotene (µg/day).


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskSee Table 1

Allocation concealment (selection bias)Unclear riskSee Table 1

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskSee Table 1

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskSee Table 1

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskSee Table 1

Tilley 1999

MethodsCluster RCT. Data were analysed at the level of the individual, allowing for difference in covariates between control and treatment worksites. The denominator used in this review is the worksite.


Participants28 car industry worksites in USA randomised. 5042 automobile employees believed to be at increased risk of colorectal cancer. 96% men, mean age 55.5 years.


InterventionsScreening programme for colorectal cancer plus nutritional intervention and educational booklet. Nutritional intervention included worksite classes encouraging increased fruit and vegetable and fibre and reduced fat consumption, self help materials and feedback from food frequency questionnaires. Newsletters were mailed quarterly. The intervention was repeated in year 2 of the trial. The control group received the screening program only. Follow-up at 12 months and 2 years. 2 year follow-up was used in the analysis.


OutcomesTotal dietary fat (% Kcal), fruit and vegetable servings per day.


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskSee Table 1

Allocation concealment (selection bias)Unclear riskSee Table 1

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskSee Table 1

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskSee Table 1

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskSee Table 1

TOHP I

MethodsMulticentre RCT of parallel group design.


ParticipantsHigh risk - DBP 80-89 mmHg not on antihypertensive medication recruited from 10 medical centres in the USA. 2182 participants randomised overall, 744 to the sodium reduction trial. 71.3% were men, age range 30-54 years.


InterventionsSeveral non-pharmacological interventions aimed at reducing blood pressure. This review is concerned only with the intervention to reduce sodium. Intervention administered by trained professionals and involved participant education and motivation, skills to change behaviour, goal setting and problem solving. The objective was to decrease urinary sodium to less than 80 mmol/24 hours. The intervention included 8 group and 2 individual sessions in the first 3 months with less frequent counselling thereafter but a minimum contact of 1 individual meeting every 2 months. No details given regarding the comparison group. Follow-up at 6, 12 and 18 months. Data abstracted for 12 months for urinary sodium and 18 months for blood pressure.


OutcomesSBP, DBP, urinary sodium, clinical events from long-term follow-up at 10-15 years (Cook 2007).


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskSee Table 1

Allocation concealment (selection bias)Unclear riskSee Table 1

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskSee Table 1

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskSee Table 1

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskSee Table 1

TOHP II

MethodsMulticentre RCT of parallel group design.


ParticipantsHigh risk - moderately overweight with high normal DBP - 83-89 mm Hg recruited from 9 medical centres in the USA. 2382 participants randomised, 66.6% men, mean age 43.7 years.


InterventionsTwo interventions - one to promote weight loss, the other to reduce sodium intake. This review is concerned only with the latter. Goal was to reduce sodium intake to 80 mmol/day. Group sessions and counselling weekly for 10 weeks, then 4 monthly sessions followed by 1 or 2 monthly contacts and refresher sessions offered. Sessions provided core knowledge and behavioural skills to reduce sodium intake. Intervention administered by trained dietitians, psychologists and health counsellors. Comparison group received no active intervention. Follow-up was at 6, 18 and 36 months. The 3 year follow-up was used in the analysis.


OutcomesSBP, DBP, urinary sodium, clinical events from long-term follow-up at 10-15 years (Cook 2007).


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskSee Table 1

Allocation concealment (selection bias)Unclear riskSee Table 1

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskSee Table 1

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskSee Table 1

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskSee Table 1

van der Veen 2002

MethodsCluster RCT. Data were analysed at the level of the individual, allowing for clustering within GP practices. The denominator used in this review is the GP practice.


ParticipantsParticipants at elevated risk of CVD recruited from 9 GP practices joining the Nijmegen Monitoring Project, University Medical Centre St Radboud, Netherlands. Eligibility criteria included a dietary fat intake of >37% or saturated fat intake of >12%, hypertension, diabetes, total cholesterol ≥6.2mmol/L but no manifest CVD. 89% of control participants had hypertension at baseline, and 7% had diabetes. The 9 GP practices included 143 individuals, 26.5% men, mean age 58 years.


InterventionsStage matched nutrition counselling performed by GPs with selective referral to dieticians if patients reached the action stage (stages of change model). In precontemplation counselling is aimed at raising consiousness about dietary behaviour and on motivation to change dietary behaviour in the contemplation stage. Individuals met with the GP on 3 occasions 2 weeks apart for approximately 10 minutes. If participants reached the action stage and were referred to the dietician there were 3 appointments - the first was 30-40 minutes, the other 2 were 10-15 minutes, appointments were 2-8 weeks apart. Counselling focused on decreasing saturated fat intake and was tailored to the individual. Participants in the control group received usual care. Follow-up was at 12 months.


OutcomesPlasma total cholesterol (mg/dl converted to mmol/l), total fat %Kcal and saturated fat %Kcal.


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskSee Table 1

Allocation concealment (selection bias)Unclear riskSee Table 1

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskSee Table 1

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskSee Table 1

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskSee Table 1

 
Characteristics of excluded studies [ordered by study ID]

StudyReason for exclusion

Anderson 2001Greater than 20% of participants were lost to follow-up.

Appel 2001Greater than 10% of participants were taking antihypertensive drugs during the course of the trial.

Bhargava 2004Greater than 20% of participants were lost to follow-up.

Boyd 1990Outcomes are reported in only 70% of those participants randomised.

Braeckman 1999Additional data were provided by the authors to allow analysis in meta-view but unfortunately the numbers of participants followed up for the outcomes of interest were poor at approximately 60% of those randomised.

Burke 2005Greater than 25% of participants had a history of CVD.

Cappuccio 2006Control group did not receive minimal intervention or no intervention.

Chalmers 1986Data available in the published report could not be used as the baseline data and changes in DBP with the intervention relative to baseline were missing. The authors were contacted, but unfortunately these data could not be retrieved given the age of this study.

Colombo 2005Control group did not receive minimal intervention or no intervention.

Djuric 2009Differential loss to follow-up of 23% in the intervention group.

Due 2008Control group did not receive minimal intervention or no intervention.

Eid 2006Greater than 25% of participants had verified CVD at baseline.

Estruch 2006Greater than 50% of participants had type-2 diabetes at baseline.

Fehily 1983Data available in the published report could not be used as the baseline data and changes in total, HDL and LDL cholesterol with the intervention relative to baseline were missing. This additional data was requested from the authors but there was no response after several attempts to contact them.

Fitzgibbon 2004Greater than 20% of participants were lost to follow-up.

Fries 2005Greater than 20% of participants were lost to follow-up.

Havas 200320% of participants were pregnant during the trial. Pregnancy was an exclusion criteria.

Hellenius 1997Longer-term follow-up of Hellenius 1993 which is included in the review. These data are excluded as further advice is given in both the intervention and control group at 6 months if participants still had raised CVD risk factors, 10/40 in the intervention group and 15/39 in the control group. Follow-up at 18 months is therefore not used and the 6 month follow-up data (Hellenius 1993) is included in the review.

Henkin 2000RCT of effect of dietitian advice over and above physician advice. Control group did not receive minimal intervention or no intervention.

HPTR 1990Data available in the published report could not be used as the variance at baseline for SBP, DBP and urinary sodium was missing. This additional data was requested from the authors but there was no response after several attempts to contact them.

Hunt 2001Data available in the published report on F&V could not be used as the variance at baseline and follow-up were missing. Authors were contacted but they were unable to provide missing data.

Hyman 1998Data available in the published report on total cholesterol could not be used as the variance at follow-up was missing. Authors were contacted but they were unable to provide missing data.

Iso 2002Control group did not receive minimal intervention or no intervention.

Korhonen 2003RCT of weight loss, alcohol reduction and exercise.

Larsen 2010Greater than 20% of participants were lost to follow-up and the ITT analysis was for the weight loss outcome only.

Leduc 1994Study published in abstract form only. No information regarding the participation rate or nature of the intervention. We were unable to contact the authors for further information.

Marcus 2001Greater than 20% of participants were lost to follow-up.

Martin 2006Greater than 20% of participants were lost to follow-up.

Ni Mhurchu 1998Greater than 20% of participants were lost to follow-up.

Ockene 1999Variance of outcome variables not available at follow-up. More than 10% of the control group were taking lipid lowering medication during the trial.

Resnicow 2001Data available in the published report on F&V consumption could not be used as the variance at baseline and follow-up and the number of individuals available at follow-up were missing. Authors were contacted but they were unable to provide missing data.

Richards 2006Greater than 20% of participants were lost to follow-up.

Sartorelli 2005Intervention included advice to increase exercise (multifactorial intervention). The exercise advice tended to increase walking for 30min/day (42% intervention group versus 24% control group, P=0.15 at 1 year).

Simon 1997Greater than 20% of participants were lost to follow-up.

Smith 1997Data available in the published report on dietary fat as a percentage of energy could not be used as there were missing variances at baseline and follow-up. Authors were contacted but they were unable to provide missing data.

Sorensen 1992Data available in the published report on dietary fat as a percentage of energy and dietary fibre could not be used as there were missing variances at baseline and follow-up. Authors were contacted but they were unable to provide missing data due to the age of the study.

Torjesen 1997Participants were selected to be overweight or obese, and the primary aim of the trial was weight loss.

WHI 2006There was extensive use of medications during the trial. Greater than 10% were on statins (11.8% in the intervention arm, 12.1% in the control arm), and antihypertensive medication (42.5% in the intervention group, 43.2% in the control group).

Willaing 2004Control group did not receive minimal intervention or no intervention.

Williams-PiehotaGreater than 20% of participants were lost to follow-up.

 
Comparison 1. Any dietary intervention versus no intervention

Outcome or subgroup titleNo. of studiesNo. of participantsStatistical methodEffect size

 1 Systolic blood pressure, change from baseline (mmHg)116406Mean Difference (IV, Random, 95% CI)-2.61 [-3.91, -1.31]

 2 Diastolic blood pressure, change from baseline (mmHg)116406Mean Difference (IV, Random, 95% CI)-1.45 [-2.22, -0.68]

 3 Urinary sodium output (mmol/24 hr), change from baseline51691Mean Difference (IV, Random, 95% CI)-40.92 [-56.54, -25.29]

 4 Urinary potassium output (mmol/24hr), change from baseline2158Mean Difference (IV, Random, 95% CI)10.81 [-3.92, 25.54]

 5 Total cholesterol (mmol/l), change from baseline223044Mean Difference (IV, Random, 95% CI)-0.13 [-0.21, -0.05]

 6 LDL cholesterol (mmol/l), change from baseline171654Mean Difference (IV, Random, 95% CI)-0.16 [-0.24, -0.08]

 7 HDL cholesterol (mmol/l), change from baseline161700Mean Difference (IV, Random, 95% CI)-6.89 [-0.02, 0.02]

 8 Triglycerides (mmol/l), change from baseline8648Mean Difference (IV, Random, 95% CI)-0.02 [-0.13, 0.08]

 9 Plasma alpha-carotene (nanomol/L), change from baseline4779Mean Difference (IV, Random, 95% CI)368.29 [-125.86, 862.44]

 10 Plasma ß-carotene (nanomol/L), change from baseline4765Mean Difference (IV, Random, 95% CI)272.05 [-52.03, 596.14]

 11 Plasma lycopene (micromol/L), change from baseline4807Mean Difference (IV, Random, 95% CI)-0.01 [-0.04, 0.01]

 12 Plasma lutein (micromol/L), change from baseline4798Mean Difference (IV, Random, 95% CI)0.02 [0.00, 0.04]

 13 Plasma beta-cryptoxanthin (micromol/L), change from baseline4772Mean Difference (IV, Random, 95% CI)0.07 [0.02, 0.11]

 14 Plasma alpha-tocopherol (micromol/L), change from baseline3750Mean Difference (IV, Random, 95% CI)-3.11 [-8.87, 2.65]

 15 Plasma gamma-tocopherol (micromol/L), change from baseline3750Mean Difference (IV, Random, 95% CI)-0.33 [-1.07, 0.41]

 16 Plasma ascorbic acid (micromol/L), change from baseline3750Mean Difference (IV, Random, 95% CI)12.47 [-18.81, 43.75]

 17 Plasma total carotenoids (micromol/L), change from baseline2113Mean Difference (IV, Random, 95% CI)0.97 [-0.84, 2.78]

 18 Total dietary fat (% Kcal)236364Mean Difference (IV, Random, 95% CI)-4.48 [-6.48, -2.47]

 19 Dietary saturated fatty acids (% Kcal)133251Mean Difference (IV, Random, 95% CI)-2.39 [-3.37, -1.40]

 20 Fruit and vegetable (servings per day), change from baseline198456Mean Difference (IV, Random, 95% CI)1.18 [0.65, 1.71]

 21 Fruit (servings per day), change from baseline94439Mean Difference (IV, Random, 95% CI)0.67 [0.07, 1.28]

 22 Vegetable (servings per day), change from baseline84412Mean Difference (IV, Random, 95% CI)0.92 [0.34, 1.49]

 23 Dietary fibre (grams per day), change from baseline113105Mean Difference (IV, Random, 95% CI)6.51 [2.20, 10.82]

 24 Dietary intake of ascorbic acid (mg/day), change from baseline52335Mean Difference (IV, Random, 95% CI)53.39 [31.97, 74.80]

 25 Dietary intake of beta-carotene (mg/day), change from baseline3542Mean Difference (IV, Random, 95% CI)3.39 [1.20, 5.59]

 26 Dietary intake of folate (μg/day), change from baseline31869Mean Difference (IV, Random, 95% CI)173.40 [101.06, 245.74]

 
Comparison 2. Subgroup analyses

Outcome or subgroup titleNo. of studiesNo. of participantsStatistical methodEffect size

 1 Total cholesterol (gender)222795Mean Difference (IV, Random, 95% CI)-0.15 [-0.24, -0.06]

    1.1 Women
5557Mean Difference (IV, Random, 95% CI)-0.02 [-0.23, 0.19]

    1.2 Men
5484Mean Difference (IV, Random, 95% CI)-0.24 [-0.39, -0.09]

    1.3 Mixed
121754Mean Difference (IV, Random, 95% CI)-0.15 [-0.28, -0.02]

 2 Total dietary fat (gender)226304Mean Difference (IV, Random, 95% CI)-4.47 [-6.54, -2.40]

    2.1 Women
83208Mean Difference (IV, Random, 95% CI)-6.77 [-10.01, -3.53]

    2.2 Men
3186Mean Difference (IV, Random, 95% CI)-3.11 [-4.79, -1.42]

    2.3 Mixed
112910Mean Difference (IV, Random, 95% CI)-3.18 [-6.52, 0.15]

 3 Fruit & vegetable servings/day (gender)208509Mean Difference (IV, Random, 95% CI)1.20 [0.67, 1.72]

    3.1 Women
51298Mean Difference (IV, Random, 95% CI)1.98 [0.96, 2.99]

    3.2 Men
21214Mean Difference (IV, Random, 95% CI)1.43 [-0.60, 3.47]

    3.3 Mixed
135997Mean Difference (IV, Random, 95% CI)0.82 [0.31, 1.33]

 4 Total cholesterol (risk group)223044Mean Difference (IV, Random, 95% CI)-0.13 [-0.21, -0.05]

    4.1 General population
41590Mean Difference (IV, Random, 95% CI)-0.05 [-0.17, 0.07]

    4.2 CVD risk high
151353Mean Difference (IV, Random, 95% CI)-0.18 [-0.28, -0.07]

    4.3 Cancer risk high
3101Mean Difference (IV, Random, 95% CI)-0.13 [-0.46, 0.20]

 5 Total dietary fat (risk group)226304Mean Difference (IV, Random, 95% CI)-4.47 [-6.54, -2.40]

    5.1 General population
93433Mean Difference (IV, Random, 95% CI)-3.92 [-7.46, -0.38]

    5.2 CVD risk high
9744Mean Difference (IV, Random, 95% CI)-3.40 [-4.83, -1.98]

    5.3 Cancer risk high
42127Mean Difference (IV, Random, 95% CI)-8.86 [-13.68, -4.04]

 6 Fruit & vegetable servings/day (risk group)198456Mean Difference (IV, Random, 95% CI)1.18 [0.65, 1.71]

    6.1 General population
146362Mean Difference (IV, Random, 95% CI)0.57 [0.28, 0.86]

   6.2 CVD risk high
00Mean Difference (IV, Random, 95% CI)0.0 [0.0, 0.0]

    6.3 Cancer risk high
52094Mean Difference (IV, Random, 95% CI)2.69 [1.53, 3.85]

 7 SBP mmHg (risk group)116406Mean Difference (IV, Random, 95% CI)-2.61 [-3.91, -1.31]

    7.1 General population
34317Mean Difference (IV, Random, 95% CI)-2.18 [-4.47, 0.11]

    7.2 CVD high risk
82089Mean Difference (IV, Random, 95% CI)-2.95 [-4.76, -1.14]

 8 DBP mmHg (risk group)116406Mean Difference (IV, Random, 95% CI)-1.45 [-2.22, -0.68]

    8.1 General population
34317Mean Difference (IV, Random, 95% CI)-0.84 [-1.74, 0.07]

    8.2 CVD high risk
82089Mean Difference (IV, Random, 95% CI)-1.97 [-3.12, -0.82]

 9 Total cholesterol (setting)223044Mean Difference (IV, Random, 95% CI)-0.13 [-0.21, -0.05]

    9.1 Healthcare settings
202899Mean Difference (IV, Random, 95% CI)-0.11 [-0.19, -0.03]

    9.2 Community/workplace/home settings
2145Mean Difference (IV, Random, 95% CI)-0.27 [-0.47, -0.07]

 10 Total dietary fat (setting)226304Mean Difference (IV, Random, 95% CI)-4.47 [-6.54, -2.40]

    10.1 Healthcare settings
155629Mean Difference (IV, Random, 95% CI)-5.38 [-7.84, -2.92]

    10.2 Community/workplace/home settings
7675Mean Difference (IV, Random, 95% CI)-2.39 [-3.71, -1.06]

 11 Fruit & vegetable servings/day (setting)198456Mean Difference (IV, Random, 95% CI)1.18 [0.65, 1.71]

    11.1 Healthcare settings
66383Mean Difference (IV, Random, 95% CI)1.88 [1.07, 2.70]

    11.2 Community/workplace/home settings
132073Mean Difference (IV, Random, 95% CI)0.76 [0.22, 1.30]

 12 Total cholesterol (intensity)223044Mean Difference (IV, Random, 95% CI)-0.13 [-0.21, -0.05]

    12.1 Low intensity
111638Mean Difference (IV, Random, 95% CI)-0.04 [-0.12, 0.03]

    12.2 High intensity
111406Mean Difference (IV, Random, 95% CI)-0.20 [-0.34, -0.06]

 13 Total dietary fat (intensity)226304Mean Difference (IV, Random, 95% CI)-4.47 [-6.54, -2.40]

    13.1 Low intensity
6725Mean Difference (IV, Random, 95% CI)-1.68 [-3.13, -0.23]

    13.2 High intensity
165579Mean Difference (IV, Random, 95% CI)-5.47 [-7.49, -3.45]

 14 Fruit & vegetable servings/day (intensity)198456Mean Difference (IV, Random, 95% CI)1.18 [0.65, 1.71]

    14.1 Low intensity
75625Mean Difference (IV, Random, 95% CI)0.66 [0.20, 1.11]

    14.2 High intensity
122831Mean Difference (IV, Random, 95% CI)1.49 [0.67, 2.30]

 15 SBP mmHg (intensity)116406Mean Difference (IV, Random, 95% CI)-2.61 [-3.91, -1.31]

    15.1 Low intensity
84574Mean Difference (IV, Random, 95% CI)-2.41 [-4.72, -0.09]

    15.2 High intensity
31832Mean Difference (IV, Random, 95% CI)-2.71 [-4.36, -1.06]

 16 DBP mmHg (intensity)116406Mean Difference (IV, Random, 95% CI)-1.45 [-2.22, -0.68]

    16.1 Low intensity
84574Mean Difference (IV, Random, 95% CI)-1.39 [-2.68, -0.10]

    16.2 High intensity
31832Mean Difference (IV, Random, 95% CI)-1.57 [-2.62, -0.52]

 17 Total cholesterol (duration)223044Mean Difference (IV, Random, 95% CI)-0.13 [-0.21, -0.05]

    17.1 Short duration (3-6 months)
121868Mean Difference (IV, Random, 95% CI)-0.10 [-0.20, 0.00]

    17.2 Long duration (12+ months)
101176Mean Difference (IV, Random, 95% CI)-0.20 [-0.34, -0.05]

 18 Total dietary fat (duration)226304Mean Difference (IV, Random, 95% CI)-4.47 [-6.54, -2.40]

    18.1 Short duration (3-6 months)
92520Mean Difference (IV, Random, 95% CI)-4.22 [-7.53, -0.92]

    18.2 Long duration ( 12+ months)
133784Mean Difference (IV, Random, 95% CI)-4.60 [-7.58, -1.62]

 19 Fruit & vegetable servings/day (duration)198456Mean Difference (IV, Random, 95% CI)1.18 [0.65, 1.71]

    19.1 Short duration (6-8 months)
91432Mean Difference (IV, Random, 95% CI)1.24 [0.49, 1.99]

    19.2 Long duration (12+ months)
107024Mean Difference (IV, Random, 95% CI)1.12 [0.34, 1.90]

 20 SBP mmHg (duration)116406Mean Difference (IV, Random, 95% CI)-2.61 [-3.91, -1.31]

    20.1 Short duration (3-6 months)
5954Mean Difference (IV, Random, 95% CI)-3.21 [-6.97, 0.54]

    20.2 Long duration 12+ months
65452Mean Difference (IV, Random, 95% CI)-2.04 [-2.98, -1.09]

 21 DBP mmHg (duration)116406Mean Difference (IV, Random, 95% CI)-1.45 [-2.22, -0.68]

    21.1 Short duration (3-6 months)
5954Mean Difference (IV, Random, 95% CI)-2.32 [-4.42, -0.21]

    21.2 Long duration (12+ months)
65452Mean Difference (IV, Random, 95% CI)-1.07 [-1.58, -0.56]

 
Table 1. Risk of bias of included studies

Study IDRandomisationAlloc. concealmentBlinding?Loss to follow-up

AmmermanUnclearUnclearUnclear13% loss to follow-up at 3 months, 27% at 6 months. Data have been analysed at 3 months

AndersonStratified systematic random procedureUnclearUnclear17.5% loss to follow-up over 12 months

AnderssenUnclearUnclearUnclearNo losses to follow-up were reported

BaronUnclearUnclearUnclear18% loss to follow-up at 3 months

BeckmannUnclearUnclearUnclearNo details, stated used ITT analysis

BeresfordRandom numbersUnclear.Interviewer and participants blind to group allocation14% of individuals lost to follow-up over 12 months

BloembergUnclearUnclearOutcome assessors1% loss to follow-up over 6 months

BowenStratified randomisation of religious organisations by denomination, size, baseline response rate, percentage of families and education level.UnclearUnclear9.4% of the intervention group and 11% of the control group were lost to follow-up at 12 months

BrekkeMinimisation method for small clinical trials (Altman) to balance a large number of strataUnclearUnclear8.5% of individuals lost to follow-up over 12 months

BullerUnclearAdequate. Project statisticianUnclearClusters analysed, but response rate to follow-up surveys for individuals only 64% at 6 months

ChengRandom number tableUnclearUnclear16% of individuals lost to follow-up at 4 months

Coates WHR MPUnclearUnclearUnclear19% of the intervention group lost to follow-up at 6 months, at 12 months loss to follow-up was 33%, at 2 years 76%

CoxLottery methodUnclearUnclearNone reported from the CVD arm of the trial

DjuricUnclearUnclearUnclear16.3% of individuals lost to follow-up over 12 months, 37% at 2 years. Data were analysed at 12 months

ElderUnclearUnclearUnclear12.3% loss to follow-up at 12 weeks, 21.5% at 12 months. Data have been analysed at 12 weeks

ENCOREComputer programmeAdequate - sealed envelopesOutcome assessorsNo losses in the intervention group, 2% loss to follow-up in the control group over 4 months

FuemmelerUnclearUnclearUnclearClusters analysed, no loss of clusters, 16% of individuals lost to follow-up over 12 months

GannRandom number tableUnclearUnclear16.9% of individuals lost to follow-up over 12 months

HavasUnclearUnclearUnclearI of 16 sites excluded - 6.25%

HelleniusUnclearUnclearUnclear2% loss to follow-up over 6 months

Henderson WHT VUnclearUnclearUnclear5.3% loss to follow-up over 24 months

JohnComputer generated randomisation listUnclearUnclear7.7% of individuals lost to follow-up over 6 months

KeyserlingUnclearUnclearUnclear8% loss to follow-up for blood analyses

KoopmanUnclearUnclearUnclear14% loss to follow-up over 3 months

KristalUnclearUnclearUnclear13.5% loss to follow-up over 12 months

LittleRandom number tableAdequate - opaque sealed envelopesUnclear14% lost to follow-up for prompt plus salt and control group at 6 months. 27% loss to follow-up in the prompt group - these data were excluded

LutzUnclearUnclearUnclear19% loss to follow-up at 6 months

MaskarinecUnclearUnclearUnclear12% loss to follow-up over 6 months

MoyUnclearUnclearUnclear23% lost to follow-up over 12 months but authors used ITT analysis

NeilList of consecutive random treatment assignmentsUnclearOutcome assessors9.7% loss to follow-up

RiddellUnclearUnclearUnclear4.5% loss to follow-up at 12 weeks

RockUnclearUnclearUnclear5.4% of individuals lost to follow-up over 6 months

SacerdoteRandom numbers generated by computerUnclearOutcome assessors6.4% lost to follow-up over 12 months

SchatzkinComputer program of random numbersAdequate. Telephone coordinating centreUnclear8.4% loss to follow-up over 4 years

SilmanUnclearUnclearUnclear16.6% in the intervention group and 6.3% in the control group were lost to follow-up for the outcome BP over 12 months

Smith-WarnerUnclearUnclearUnclear8% loss to follow-up at 12 months

SorensenUnclearUnclearUnclear3.9% individuals lost to follow-up at 19.5 months

StevensUnclearUnclearUnclear13% lost to follow-up over 12 months

TakahashiUnclearUnclearUnclear2.9% loss to follow-up for questionnaire-based outcomes, 17.2% for blood pressure outcomes over 12 months

TilleyRandom number tableUnclearUnclear1.6% individuals lost to follow-up at 12 months, 3.5% at 24 months

TOHP IUnclearUnclearOutcome assessors20% loss to follow-up over 12 months

TOHP IIUnclearAdequate. Telephone coordinating centre or opaque envelopesOutcome assessors7.5% loss to follow-up at 18 months

van der VeenUnclearUnclearUnclearClusters analysed, no loss of clusters but 9% of individuals lost to follow-up over 12 months

 
Table 2. Initial mean level of risk factors in control group of included studies

Study IDCholesterol mmol/lBlood pressure mmHg

Ammerman 20036.63not available

Anderson 19925.9not available

Anderssen 20076.4134/90

Baron 1990 men4.8not available

Baron 1990 women4.9not available

Beckmann 19956.12mean standing BP 112

Bloemberg 19917.0not available

Brekke 20054.95not available

Coates 1999 HT MP5.7not available

Cheng 20046.0not available

Djuric 20064.43not available

ENCORE5.33138/86

Hellenius 19936.0130/82

John 20025.12129/80

Keyserling 19976.5not available

Koopman 1990not available144/95

Little 2004not available154/93

Moy 2001not availablenot available

Neil 19957.4not available

Sacerdote 2006not available129/79

Silmannot available161/98

Stevens 20036.01not available

Takahashi 2006not available128/76

TOHP Inot available125/84

TOHP II 1997not available127/86

van der Veen 20026.6not available

 
Table 3. Clinical events reported from long-term follow-up of participants recruited to TOHP I and TOHP II

TOHP IHazard Ratio95% Confidence IntervalP value

CVD combined endpoint0.590.33, 1.080.086

Non-fatal MI0.30.1, 0.950.041

Non-fatal stroke2.10.49, 8.960.32

Revascularisation0.670.28, 1.610.37

CVD mortality0.170.02, 1.410.1

TOHP IIHazard Ratio95% Confidence IntervalP value

CVD combined endpoint0.810.59, 1.120.2

Non-fatal MI0.90.55, 1.460.66

Non-fatal stroke0.50.18, 1.360.18

Revascularisation0.680.41, 1.140.14

CVD mortality0.90.36, 2.280.83