Intervention Review

You have free access to this content

Isoflavones for hypercholesterolaemia in adults

  1. Yu Qin1,
  2. Kai Niu2,
  3. Yuan Zeng1,
  4. Peng Liu1,
  5. Long Yi1,
  6. Ting Zhang1,
  7. Qian Yong Zhang1,
  8. Jun Dong Zhu1,
  9. Man Tian Mi1,*

Editorial Group: Cochrane Metabolic and Endocrine Disorders Group

Published Online: 6 JUN 2013

Assessed as up-to-date: 30 SEP 2012

DOI: 10.1002/14651858.CD009518.pub2


How to Cite

Qin Y, Niu K, Zeng Y, Liu P, Yi L, Zhang T, Zhang QY, Zhu JD, Mi MT. Isoflavones for hypercholesterolaemia in adults. Cochrane Database of Systematic Reviews 2013, Issue 6. Art. No.: CD009518. DOI: 10.1002/14651858.CD009518.pub2.

Author Information

  1. 1

    Third Military Medical University, Nutrition, Chongqing, Chongqing, China

  2. 2

    Third Military medical University, Cancer, Xinqiao Hospital, Chongqing, China

*Man Tian Mi, Nutrition, Third Military Medical University, No 30, Gaotanyan Street, Chongqing, Chongqing, 400038, China. mimantian@hotmail.com.

Publication History

  1. Publication Status: New
  2. Published Online: 6 JUN 2013

SEARCH

 
Characteristics of included studies [ordered by study ID]
Aubertin-Leheudre 2008

MethodsParallel randomised controlled clinical trial, randomisation ratio 1 : 1


ParticipantsInclusion criteria: postmenopausal women aged 50-70 years, obese (fat mass > 40%), without major physical incapacity, without hormone therapy (at the time of the study, women had never been on hormone therapy or were off hormone therapy for at least 1 year), sedentary (practiced 3 hours/wk of physical activities), weight stable (2 kg) for the last 6 months, non-smoker, moderate drinking (maximum 15 g of alcohol/d, the equivalent of 1 alcoholic beverage/d), no medication that could influence body composition and metabolism, and absence of menses for the past 12 months

Exclusion criteria: no

Diagnostic criteria: not specified


InterventionsNumber of study centres: 1

Treatment before study: no

Titration period: 6 months


OutcomesOutcomes reported in abstract of publication: body composition, medical and social characteristics, daily energy expenditure, dietary intake and blood biochemical analyses (lipid profile, insulin, glucose)


Study detailsRun-in period: no

Study terminated before regular end (for benefit/because of adverse events): no


Publication detailsLanguage of publication: English

Commercial funding: not reported

Non-commercial/other funding: supported by the Canadian Institutes of Health Research (CIHR) and the Research Centre on Aging

Publication status: peer-reviewed journal


Stated aim of studyQuote from publication: "To investigate whether 6 months of isoflavone supplementation, which has been shown to be sufficient to improve menopausal symptoms, could also improve clinical cardiovascular disease (CVD) risk factors in obese postmenopausal women, compared with a placebo"


NotesNot all participants were hypercholesterolaemic. The authors provided the data of participants with the baseline cholesterol higher than 5.2 mmol/L. 8 and 11 women with hypercholesterolaemia in the isoflavones and placebo groups, respectively, completed the trial. Thus, this trial was included


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskQuote from publication: "Women were randomly assigned to one of two groups, isoflavones (ISO) or placebo (PLA)"

Comment: no information about sequence generation

Allocation concealment (selection bias)Unclear riskComment: no information about concealment

Blinding of participants and personnel (performance bias)
All outcomes
Low riskQuote from publication: "Identical active and placebo capsules were supplied and encapsulated by Arkopharma Ltd. (Carros, France)"

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskComment: no information about blinding

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskQuote from publication: "Among these 50 participants, 39 completed the study (21 in ISO vs. 18 in PLA)"

Comment: number of participants analyzed was less than number of participants randomized

Selective reporting (reporting bias)Low riskComment: none detected

Other biasLow riskComment: no other sources of bias were found in this study

Dewell 2002

MethodsParallel randomised controlled clinical trial, randomisation ratio intervention: control = 5 : 4


ParticipantsInclusion criteria: healthy moderately hypercholesterolaemic (mean TC 6.6 ± 1.3 mmol/L) postmenopausal women (mean age 69 ± 4 years)

Exclusion criteria: receiving hormone replacement therapy, clinical or biochemical evidence of diabetes or renal, hepatic or cardiovascular disease

Diagnostic criteria: not specified


InterventionsNumber of study centres: 1

Treatment before study: two individuals were taking medication known to affect carbohydrate or lipid metabolism. 1 woman was taking simvastatin and 1 woman fluvastatin for hypercholesterolaemia. Both women had been on a stable dose for at least 1 year before the study, and medications were not altered during the study period

Titration period: 6 months


OutcomesOutcomes reported in abstract of publication: triacylglycerol, TC and HDL-C


Study detailsRun-in period: no

Study terminated before regular end (for benefit/because of adverse events): no


Publication detailsLanguage of publication: English

Commercial funding: not reported

Non-commercial/other funding: yes; a small research grant from the College of Applied Sciences and Arts at San Jose State University and a research award from the Circle of Friends/Department of Nutrition and Food Science of San Jose State University

Publication status: peer-reviewed journal


Stated aim of studyQuote from publication: "to investigate the effects of PE supplementation (150 mg) on serum lipids and lipoproteins in moderately hypercholesterolemic, elderly, postmenopausal women"


NotesThe trial reported the outcomes of HDL-C and non-HDL-C at baseline and at 2 months, but no data at 6 months

Abbreviations: HDL: high-density-lipoprotein


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskQuote from publication: "Thirty-six subjects were randomized into two groups"

Comment: no information about sequence generation

Allocation concealment (selection bias)Unclear riskComment: no information about concealment

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskQuote from publication: "Subjects were recruited initially as part of a larger randomized, double blind, placebo-controlled trial with a parallel design to assess the role of PE supplementation on bone mineral health"

Comment: no information about blinding

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskComment: no information about blinding

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskQuote from publication: "Because of the unavailability of serum, determinations of triacylglycerol and cholesterol concentrations at 6 months were performed only on 17 and 18 of the 20 subjects in the PE-treated group, respectively"

Comment: number of participants analyzed was less than number of participants randomized

Selective reporting (reporting bias)Low riskComment: none detected

Other biasLow riskComment: no other sources of bias were found in this study

Gardner 2001

MethodsParallel randomised controlled clinical trial, randomisation ratio 1 : 1


ParticipantsInclusion criteria: the fasting plasma LDL-cholesterol concentration of 3.37-4.92 mmol/L (130-190 mg/dL) and a triacylglycerol concentration < 2.82 mmol/L (< 250 mg/dL); postmenopausal (≥ 1 year since their last menstrual cycle), age < 80 years, and a BMI of 20–31 kg/m2

Exclusion criteria: smokers, had been taking hormone replacements or lipid-lowering medication during the previous 3 months, had a history of cardiovascular disease or diabetes, or had breast, endometrial or ovarian cancer in the previous 10 years

Diagnostic criteria: not specified


InterventionsNumber of study centres: 1

Treatment before study: no

Titration period: 12 wks


OutcomesOutcomes reported in abstract of publication: TC, LDL-C, HDL-C and triacylglycerol


Study detailsRun-in period: yes

Study terminated before regular end (for benefit/because of adverse events): no


Publication detailsLanguage of publication: English

Commercial/non-commercial/other funding: not reported

Publication status: peer-reviewed journal


Stated aim of studyQuote from publication: "to determine the effect of soy protein and isoflavones on plasma lipid concentrations in postmenopausal, moderately hypercholesterolemic women"


Notes"LDL-cholesterol was calculated according to the method of Friedewald unless the triacylglycerols were > 4.52 mmol/L (> 400 mg/dL), in which case the LDL-C value was considered missing data (3 LDL-cholesterol data points were excluded: 1 in the Milk group, 0 in the Soy– group, and 2 in the Soy+ group)"

Abbreviations: HDL: high-density-lipoprotein; LDL: low-density-lipoprotein


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskQuote from publication: "The subjects were randomly assigned to 12 wk of dietary protein supplementation (42 g/d) with either a milk protein (Milk group) or 1 of 2 soy proteins containing either trace amounts of isoflavones (Soy– group) or 80 mg aglycone isoflavones (Soy+ group)", "Randomization was performed in blocks of 30 participants"

Comment: no details provided

Allocation concealment (selection bias)Low riskQuote from publication: "Dietary supplements containing a mixture of protein, carbohydrate, and calcium in powder form (Shaklee Corporation, Hayward, CA) were provided in sealed packets, each containing one-half of the daily dose (21 g protein/packet 2 packets/d)", "All supplements were formulated to be identical in taste, color, and odor"

Blinding of participants and personnel (performance bias)
All outcomes
Low riskQuote from publication: "Participants, investigators, study staff, and laboratory technicians were blinded to treatment assignments until the conclusion of the trial"

Blinding of outcome assessment (detection bias)
All outcomes
Low riskQuote from publication: "Participants, investigators, study staff, and laboratory technicians were blinded to treatment assignments until the conclusion of the trial"

Incomplete outcome data (attrition bias)
All outcomes
High riskQuote from publication: "These analyses showed a stable composition of isoflavone concentrations throughout the study (data not shown)", "Of the 115 women who entered the study, 21 withdrew before study completion", "Statistical analyses were performed on data"

Comment: number of participants analyzed was less than number of participants randomized

Selective reporting (reporting bias)Low riskComment: none detected

Other biasHigh riskQuote "At the onset of the study, the participants were instructed to take the full dose of the protein supplements. However, we had a higher than anticipated dropout rate early in the study because of adverse gastrointestinal responses to the acute dietary change. Therefore, gradual adaptation to the protein supplements was recommended for the latter four-fifths of participants. These participants began the 4-wk run-in phase by consuming one-half of the goal dose rather than the full dose. These participants were then encouraged to increase their intake to the full dose by week 3 of the run-in phase". "Exceptions to group comparability at randomization included a higher average age and a higher number of years since menopause in the Soy+ group and a lower percentage of married women in the Soy– group than in the Soy+ group"

Comment: not all participants performed the run-in phase; several baseline characteristics of participants were not equally distributed between the intervention and placebo groups

Mackey 2000

MethodsParallel randomised controlled clinical trial, randomisation ratio not reported


ParticipantsInclusion criteria: postmenopausal women aged 45-65 years

Exclusion criteria: a history of allergy to soy or if any of them were taking cholesterol-lowing agents

Diagnostic criteria: a fasting TC > 5.5 mmol/L


InterventionsNumber of study centres: 1

Treatment before study: no

Titration period: 12 wks


OutcomesOutcomes reported in abstract of publication: TC, LDL-C, HDL-C, SHBG and LH


Study detailsRun-in period: yes

Study terminated before regular end (for benefit/because of adverse events): no


Publication detailsLanguage of publication: English

Commercial funding: yes

Publication status: peer-reviewed journal


Stated aim of studyQuote from publication: "We performed a series of studies in men and women using soy protein with or without isoflavones to study the effect on the lipoprotein profile as well as other biochemical indices such as sex hormones, pituitary hormones, markers of bone turnover and glucose tolerance"


NotesThe female study was a prospective, double-blind, randomised controlled study. The male study was an open prospective observational pilot study. Thus, only female study was included. The concentrations of LDL-C maybe calculated

Abbreviations: HDL: high-density-lipoprotein; LDL: low-density-lipoprotein


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskQuote from publication: "Fifty four female subjects were randomised to receive 28 g of protein powder; either a) a soy protein with an isoflavone content of 65 mg isoflavones daily (ISP+) or b) a soy protein isolate with less than 4 mg isoflavones per daily (ISP-)"

Comment: no information about sequence generation

Allocation concealment (selection bias)Unclear riskComment: no information about concealment

Blinding of participants and personnel (performance bias)
All outcomes
Low riskQuote from publication: "The female study was a prospective, double-blind, randomised controlled study"

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskComment: no information about blinding

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskQuote: "Of the 54 women who were randomised into the study, 49 women completed the study"

Comment: number of participants analyzed was less than number of participants randomized

Selective reporting (reporting bias)Low riskComment: none detected

Other biasLow riskComment: no other sources of bias were found in this study

Wang 2005

MethodsParallel randomised controlled clinical trial, randomisation ratio 1 : 1


ParticipantsInclusion criteria: postmenopausal women (≥ 6 months since their last menstrual cycle) with perimenopausal symptoms, dyslipidaemia and abnormal endocrine function, aged 45-55 years

Exclusion criteria: use of steroid drugs

Diagnostic criteria: not specified


InterventionsNumber of study centres: 1

Treatment before study: no

Titration period: 3 month


OutcomesOutcomes reported in abstract of publication: serum TC, HDL-C, LDL-C and triacylglycerol


Study detailsRun-in period: no

Study terminated before regular end (for benefit/because of adverse events): no


Publication detailsLanguage of publication: Chinese

Commercial/non-commercial/other funding: not reported

Publication status: peer-reviewed journal


Stated aim of studyQuote from publication: "To study the effects of soybean isoflavones on lipids metabolism in the perimenopausal female"


NotesBaseline serum HDL-C concentrations were very low


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskQuote from publication: "Subjects were randomised to 3 groups"

Comment: no information about sequence generation

Allocation concealment (selection bias)Unclear riskComment: no information about concealment

Blinding of participants and personnel (performance bias)
All outcomes
Low riskQuote from publication:"The placebo group consumed the placebo capsules that looked like the isoflavones capsules"

Comment: participants and personnel were potentially masked

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskComment: no information about blinding

Incomplete outcome data (attrition bias)
All outcomes
Low riskComment: number of participants analyzed was equal to the number of participants randomized

Selective reporting (reporting bias)Low riskComment: none detected

Other biasLow riskComment: no other sources of bias were found in this study

 
Characteristics of excluded studies [ordered by study ID]

StudyReason for exclusion

Atkinson 2004Randomized clinical trial comparing 43.5 mg red clover-derived isoflavones versus placebo in 177 women. It was excluded because not all participants were hypercholesterolaemic

Badeau 200756 postmenopausal women were treated with either isoflavone or placebo tablets for 3 months in a cross-over design, separated by a 2-month washout period. It was excluded because not all participants were hypercholesterolaemic

Blakesmith 2003Randomized clinical trial comparing isoflavone versus placebo in 25 healthy premenopausal women. It was excluded because not all participants were hypercholesterolaemic

Cancellieri 2007Multicentre, randomized, double-blind, placebo-controlled clinical investigation on 125 menopausal women randomly assigned to 2 groups treated for 6 months with placebo or 1 tablet daily of an herbal product containing 72 mg/dose of isoflavones of different plants origin and other plant extracts. It was excluded because not all participants were hypercholesterolaemic

Chedraui 2008Randomized controlled cross-over clinical trial conducted in 60 postmenopausal women. It was excluded because not all participants were hypercholesterolaemic

Cheng 2007Randomized clinical trial comparing isoflavone versus placebo in 60 healthy postmenopausal women. It was excluded because not all participants were hypercholesterolaemic

Cianci 2012120 women with a mean age of 54.8 ±  0.6 years were enrolled and randomized to treatment with isoflavones and berberine or calcium and vitamin D(3). It was excluded because 1) not all participants were hypercholesterolaemic, and 2) intervention was isoflavones and berberine

Colacurci 2005Randomized clinical trial comparing isoflavone versus placebo in 60 healthy postmenopausal women. It was excluded because not all participants were hypercholesterolaemic

Dent 2001Randomized clinical trial comparing isoflavone-rich soy versus isoflavone-poor soy in perimenopausal women. It was excluded because not all participants were hypercholesterolaemic

Fornaro 200654 healthy postmenopausal women were randomly allocated to 60 mg/d of both genistein and daidzein for 6 months (active group, n = 27) or no therapy (control group, n = 27). It was excluded because not all participants were hypercholesterolaemic

Gallagher 2004A total of 65 women, with a mean age of 55 years and 7.5 years since menopause, were randomized to 1 of 3 groups; soy protein with 96 mg isoflavones/d, soy with 52 mg isoflavones/d, or soy without isoflavones (< 4 mg isoflavones/d). It was excluded because not all participants were hypercholesterolaemic

Garrido 200629 healthy postmenopausal women were invited to take part in a randomized study to receive either 100 mg/d isoflavone supplement (n = 15) or identical placebo capsules (n = 14). It was excluded because not all participants were hypercholesterolaemic

Gonzalez 2007A randomized, double-blind, placebo-controlled, cross-over study was conducted in 32 Caucasian, postmenopausal women with diet-controlled type 2 diabetes. It was excluded because not all participants were hypercholesterolaemic

Han 2002Randomized clinical trial comparing isoflavone versus placebo in postmenopausal women. It was excluded because not all participants were hypercholesterolaemic

Hidalgo 200560 postmenopausal women aged > 40 years, non-users of hormone therapy, with Kupperman index score 15, were randomized in a double-blind method to receive either a commercially available red clover isoflavone supplement (80 mg/d) or placebo for 90 d. It was excluded because not all participants were hypercholesterolaemic

Ho 2007A double-blind, randomized, placebo-controlled trial was conducted in 203 postmenopausal Chinese women aged 48-62 years. They were randomly assigned to receive daily doses of 500 mg calcium, and 0 mg isoflavones (placebo, n = 67), 40 mg isoflavones (n = 68) and 80 mg isoflavones (n = 68). It was excluded because not all participants were hypercholesterolaemic

Jiang 2008Randomized clinical trial comparing isoflavone versus placebo in 189 normal cholesterolaemic and hypercholesterolaemic perimenopausal women. It was excluded because lack of cholesterol data in hypercholesterolaemic women in the placebo group

Lee 2012In this randomized, double-blind, placebo-controlled trial, 51 subjects with a body mass index of 23 kg/m2 or greater and a waist-to-hip ratio of 0.90 or greater for men or 0.85 or greater for women were randomly assigned to take 9.9 g/d of either a placebo or doenjang for 12 weeks. It was excluded because 1) not all participants were hypercholesterolaemic, and 2) doenjang may contain isoflavones and soy protein

Liang 2007It was excluded because the intervention was soy lecithin

Llaneza 2010116 postmenopausal women with insulin resistance were randomly assigned to a group of Mediterranean diet and physical exercise (control group) or a group of Mediterranean diet, physical exercise and daily oral ingestion of 40 mg of soy isoflavones (soy isoflavones group). It was excluded because not all participants were hypercholesterolaemic

Marini 2010Randomized clinical trial comparing genistein versus placebo in postmenopausal women. It was excluded because not all participants were hypercholesterolaemic

Nikander 2004Randomized clinical trial comparing isoflavone versus placebo in 56 non-diabetic postmenopausal women with a history of breast cancer. It was excluded because not all participants were hypercholesterolaemic

Oliveira 2012In a prospective, randomized and single-blinded clinical trial, we compared people with chronic hepatitis C who had casein as a supplement (n = 80) (control group), with people who consumed a soy supplement diet (n = 80) (intervention group). It was excluded because 1) not all participants were hypercholesterolaemic, and 2) the intervention was soy protein and isoflavones, but the control was placebo

Ozturk 2009Randomized clinical trial comparing isoflavone versus placebo in 22 postmenopausal women. It was excluded because not all participants were hypercholesterolaemic

Petri Nahas 2004Randomized clinical trial comparing isoflavone versus placebo in 50 postmenopausal women. It was excluded because not all participants were hypercholesterolaemic

Rios 2008In this double-blind, placebo-controlled study, 47 postmenopausal women 47-66 years of age received 40 mg of isoflavone (n = 25) or 40 mg of casein placebo (n = 22). It was excluded because not all participants were hypercholesterolaemic

Schult 2004Randomized clinical trial comparing isoflavones versus placebo in 252 menopausal women aged 45-60 years. It was excluded because not all participants were hypercholesterolaemic

Swain 2002Perimenopausal women (n = 69) were randomly assigned (double blind) to treatment: isoflavone-rich soy-protein isolate (n = 24), isoflavone-poor soy-protein isolate (n = 24) or whey protein (control; n = 21). Each subject consumed 40 g soy or whey protein daily for 24 weeks. It was excluded because not all participants were hypercholesterolaemic

Terzic 2009Randomized clinical trial comparing a red clover-derived isoflavone versus placebo in 40 healthy postmenopausal women with a mean age of 56 years. It was excluded because not all participants were hypercholesterolaemic

Törmälä 200630 postmenopausal women were treated in a randomized, placebo-controlled, cross-over trial with isoflavones or placebo for 3 months interrupted by a 2-month washout period. It was excluded because not all participants were hypercholesterolaemic

Uesugi 2003Randomized clinical trial comparing isoflavone versus placebo in postmenopausal women. It was excluded because not all participants were hypercholesterolaemic

Villa 2009A randomized placebo controlled study was conducted in 50 postmenopausal women. It was excluded because not all participants were hypercholesterolaemic

Wong 2012Randomized controlled cross-over clinical trial conducted in 41 participants (23 men, 18 women). It was excluded because the intervention duration was 4 weeks

Woo 2003Randomized clinical trial comparing isoflavone versus placebo in postmenopausal women. It was excluded because not all participants were hypercholesterolaemic

Wu 2006aRandomized clinical trial comparing isoflavone versus placebo, and isoflavone plus walking versus walking in 136 postmenopausal women at < 5 years after the onset of menopause. It was excluded because the mean daily dietary isoflavones intakes of participants in all groups at baseline and during the trial were greater than 37 mg/d, and not all participants were hypercholesterolaemic. This paper was also republished

Wu 2006bRandomized clinical trial comparing isoflavone versus placebo, and isoflavone plus walking versus walking in 128 postmenopausal women at < 5 years after the onset of menopause. It was excluded because the mean daily dietary isoflavones intakes of participants in all groups at baseline and during the trial were greater than 37 mg/d, and not all participants were hypercholesterolaemic. This paper was also republished

Xiao 2003It was excluded because the intervention duration was 8 weeks

Ye 2012A randomized placebo-controlled trial. 90 early postmenopausal Chinese women, aged 45-60 years, were randomly assigned to 3 treatment groups (30 each) receiving daily doses of 0 (placebo), 84 and 126 mg of soy germ isoflavones. It was excluded because most of participants were not hypercholesterolaemic

Yildiz 2005Randomized clinical trial comparing 40 mg of genistein versus placebo in postmenopausal women. It was excluded because not all participants were hypercholesterolaemic

 
Comparison 1. Isoflavones versus placebo or soy protein+isoflavones versus soy protein

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

 1 LDL-cholesterol3132Mean Difference (IV, Random, 95% CI)-0.16 [-0.39, 0.07]

    1.1 Isoflavones versus placebo
119Mean Difference (IV, Random, 95% CI)0.05 [-0.43, 0.53]

    1.2 Soy protein-containing isoflavones versus soy protein
2113Mean Difference (IV, Random, 95% CI)-0.23 [-0.50, 0.04]

 2 Total cholesterol4166Mean Difference (IV, Random, 95% CI)-0.08 [-0.34, 0.19]

    2.1 Isoflavones versus placebo
253Mean Difference (IV, Random, 95% CI)0.12 [-0.44, 0.68]

    2.2 Soy protein-containing isoflavones versus soy protein
2113Mean Difference (IV, Random, 95% CI)-0.20 [-0.50, 0.09]

 3 HDL-cholesterol3132Mean Difference (IV, Random, 95% CI)-0.03 [-0.22, 0.16]

    3.1 Isoflavones versus placebo
119Mean Difference (IV, Random, 95% CI)-0.07 [-0.38, 0.24]

    3.2 Soy protein-containing isoflavones versus soy protein
2113Mean Difference (IV, Random, 95% CI)-0.03 [-0.30, 0.25]

 4 Triglycerides4165Mean Difference (IV, Random, 95% CI)-0.15 [-0.43, 0.13]

    4.1 Isoflavones versus placebo
252Mean Difference (IV, Random, 95% CI)-0.46 [-0.84, -0.09]

    4.2 Soy protein-containing isoflavones versus soy protein
2113Mean Difference (IV, Random, 95% CI)0.03 [-0.23, 0.29]

 5 Sex hormone binding globulin146Mean Difference (IV, Random, 95% CI)-4.22 [-15.62, 7.18]

 
Summary of findings for the main comparison.

Isoflavones for hypercholesterolaemia in adults

Patient or population: postmenopausal women with hypercholesterolaemia

Settings: outpatients or not specified

Intervention: isoflavones or soy protein-containing isoflavones

Comparison: placebo or soy protein

OutcomesRelative effect
(95% CI)
No of participants
(studies)
Quality of the evidence
(GRADE)
Comments

Cardiovascular eventsSee commentSee commentSee commentNot investigated

Death from any causeSee commentSee commentSee commentNot investigated

Health-related quality of lifeSee commentSee commentSee commentNot investigated

Adverse events

[follow-up: 3 to 6 months]
See comment208

(5)
⊕⊕⊝⊝
lowa
No serious adverse events reported

Low-density lipoprotein (LDL) cholesterol

[follow-up: 3 to 6 months]
See comment132

(3)
⊕⊝⊝⊝
very lowb
No statistically significant differences between groups

CostsSee commentSee commentSee commentNot investigated

GRADE Working Group grades of evidence
High quality: Further research is very unlikely to change our confidence in the estimate of effect.
Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate.
Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate.
Very low quality: We are very uncertain about the estimate.

 aDue to serious risk of bias, low number of participants and studies, short duration of treatment.
bDue to serious risk of bias, serious indirectness, low number of participants and studies, short duration of treatment.
 
Table 1. Overview of study populations

Characteristic

Study ID
Intervention and comparator[N]
Screened /
eligible
[N]
Randomised
[N]
Safety
[N]
ITT
[N]
Finishing study
[%]
Randomised
finishing study

Aubertin-Leheudre 2008Isoflavones (70 mg)----8N/A

Placebo---11N/A

total:---19N/A






Dewell 2002Isoflavones (150 mg)-20-2020100

Maltodextrin with 10% caramel16-1616100

total:36-3636100






Gardner 2001Isoflavones (80 mg)-34--3191.2

Trace amounts of isoflavones34--3397.1

total:68--6494.1






Mackey 2000  Isoflavones (65 mg)----25N/A

Less than 4 mg isoflavones---24N/A

total:54--4990.7






Wang 2005Isoflavones (158 mg)-20-2020100

Placebo20-2020100

total:40-4040100






Total All interventions -104

All controls -104

All interventions and comparators -208

 "-" denotes not reported.
ITT: intention-to-treat; N/A: not applicable.