SEARCH

SEARCH BY CITATION

Abstract

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. MATERIALS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. Acknowledgements
  8. Bibliography

Background:

Little is known about how many dyspeptics in the population consult medical and non-medical practitioners, or the factors associated with various consulting patterns.

Methods:

A cross-sectional survey of 748 Australians with dyspepsia investigated their age, sex, dyspepsia symptoms, medical and non-medical consultations, and health status on the SF-12.

Results:

Overall, 56% had ever consulted a medical practitioner for dyspepsia. Of these, 54% consulted within 6 months of first symptoms. Non-medical practitioners were consulted by 29%. Compared to dyspeptics in all, or most, other consulting groups, subjects who did not consult (37%, group NO) were characterized by fewer symptoms, better physical health, and younger age. Those who only consulted doctors (34%, group M) were older and had better mental, but poorer physical health. Those who only consulted non-medical practitioners (7%, group N) were younger and had better physical, but poorer mental health. Dyspeptics consulting both medical and non-medical practitioners (22%, group M + N), were older, more dissatisfied with medical care, had more symptoms and poorer physical and mental health. Timing of medical consultations was similar in groups M and M + N. Group M + N dyspeptics consulted similar types, but more non-medical practitioners than group N. No sex differences were found in consulting behaviour.

Conclusions:

Many dyspeptics do not consult; they have fewer symptoms than consulters. Consultation with non-medical practitioners is common and is associated with poor mental health. Dyspeptics seeking advice from both medical and non-medical practitioners are less satisfied with their medical management than those who only consult doctors for their dyspepsia.


INTRODUCTION

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. MATERIALS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. Acknowledgements
  8. Bibliography

Despite the high prevalence of dyspepsia in the community, the majority of dyspeptics do not consult a medical practitioner about their symptoms.1[2][3][4][5][6][7][8][9][10][11][12]–13 British surveys revealed that only 22–25% of people with dyspepsia had consulted a doctor for symptoms within the previous 6 or 12 months and only 42% ever sought medical advice.6[7][8]–9 In the United States, only 22–29% of dyspeptics consulted a doctor in the previous year.12 Reasons given by patients for consulting a medical practitioner about dyspepsia include: severity of symptoms; anxiety about symptoms; and fear of serious disease.8, 13[14]–15 Factors found to be associated with consulting a doctor about dyspepsia include: increasing age; duration of dyspepsia; severity of symptoms; frequent dyspepsia; lower socio-economic status; and experience of stressful life events.6, 7, 9, 13, 15, 16, 17 An important question, not yet answered, is whether people with dyspepsia consult at a similar stage in their illness.

Little is known about the extent to which people with dyspepsia seek the advice of other non-medical health practitioners, such as allied or alternative health practitioners. One possible hypothesis explaining why patients seek care from non-medical practitioners is dissatisfaction with medical care. Verhoef et al. found that a sample of Canadian patients with upper gastrointestinal problems, who sought alternative health care in addition to medical care, were less satisfied with, and more sceptical about, conventional medicine.18 In a further study, patients’ dissatisfaction with their gastroenterologists was identified as a reason for seeking a second opinion.19 There is a scarcity of data about dyspepsia patients’ satisfaction with medical care.

Ascertaining the proportions and profiles of people who do or do not consult various health practitioners for dyspepsia provides important information about factors precipitating consultation and assists in understanding the extent to which consulters represent the population of people with dyspepsia. As part of a cross-sectional survey to determine the prevalence of dyspepsia in an Australian population, the proportions fitting into each of four different consulting patterns were identified. These were: dyspeptics who only consult medical practitioners; those who only consult non-medical health practitioners; those who consult both; and those who do not consult. The first null hypothesis was that the four consulting groups do not differ significantly in age, sex, duration, number and severity of symptoms, and overall physical and mental health status. Furthermore, it was hypothesized that dyspeptics who consult medical practitioners and those who consult both medical and non-medical practitioners do not differ significantly in the timing of their first presentation to a doctor or in their satisfaction with medical care. Additionally, it was hypothesized that dyspeptics who only consult non-medical practitioners and those who consult both medical and non-medical practitioners consult similar numbers and types of non-medical practitioners.

MATERIALS AND METHODS

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. MATERIALS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. Acknowledgements
  8. Bibliography

Subjects

The sample consisted of 748 people with dyspepsia, collected in a random telephone survey of households which established the prevalence of dyspepsia in the state of New South Wales (NSW). NSW has a population of 6.2 million, approximately one third of the Australian population. Overall, 2300 people were interviewed, achieving a response rate of 69%. Respondents did not differ significantly from non-respondents in age or sex. Households were selected using an electronic version of residential telephone numbers. The household member to be interviewed was randomly selected according to the number of people in the household aged 18 years or over. Pregnant women were excluded. A minimum of 10 call attempts was made to each household in order to make initial contact. Once contacted, a minimum of five call-backs was made to contact the correct respondent. Data were weighted by household size and the age and sex of the NSW population. Subjects’ dyspepsia status during the last 3 months was established using the Rome I definition, namely the presence of epigastric pain or discomfort.20 Discomfort was defined as one of the following nine symptoms experienced more frequently than a one-off episode: epigastric pain; early satiety; postprandial fullness; nausea; vomiting; retching; bloating; belching/burping; or anorexia. In compliance with the Rome I definition, experience of gastro-oesophageal reflux symptoms (heartburn, acid regurgitation and food regurgitation) alone did not qualify as evidence of dyspepsia. However, people who reported dyspepsia with gastro-oesophageal reflux symptoms were included in the sample.

Materials

A structured questionnaire was developed and pilot-tested on four samples of 25 subjects. After each pilot it was revised where necessary. The questions pertinent to the present report established age, sex and the presence of dyspepsia. Subjects were asked which of the following symptoms they had experienced in the past 3 months: the nine dyspepsia symptoms (listed above); three gastro-oesophageal reflux symptoms (heartburn, acid regurgitation and food regurgitation); and dysphagia. They also rated the severity of each symptom on a validated four-point severity scale (1, very severe; 4, mild).21, 22 The total number of symptoms (possible range 1–13), and an average severity score (the subject’s severity scores were added and divided by the number of their symptoms) for each subject was calculated. Medical consultation history for dyspepsia was explored in terms of whether consultation had ever occurred, duration of symptoms at first medical consultation, whether there had been recent consultation (in the previous 3 months) and satisfaction with medical management (using a four-point scale from 1, very dissatisfied to 4, very satisfied). Respondents were asked if they had consulted any of the following non-medical health practitioners concerning their dyspepsia: naturopath; chiropractor/osteopath; dietitian/nutritionist; pharmacist; community nurse; homeopath; iridologist; acupuncturist; or any other non-medical practitioners. The above data enabled subjects to be classified into the four consulting groups. Subjects’ health status was measured by the validated SF-12 which produces two sub-scores:23 a physical (physical component score [PCS] 12) and a mental (mental component score [MCS] 12) health score.

Procedure

Experienced interviewers, all of whom underwent prior training, undertook the interviews. A CATI (computerized aided telephone interviewing) system was used to guard against problems such as missed questions and out-of-range values. Questions were randomized to avoid bias. Techniques were adopted to assist accurate recall. In order to report how long they waited before consulting a doctor, respondents needed to recall information over differing periods of time. Research on long-term recall shows that while some recall of detailed information, such as dietary history, may be poor recall of other information of importance for epidemiological studies is more reliable.24[25][26][27][28][29]–30 This is particularly so if the information has been reinforced over time and techniques are used to assist recall.31 Subjects’ recall would have been assisted by the fact that symptom experience had been reinforced over time, as all were current dyspepsia sufferers. Those required to recall over the longest periods had suffered repeated exposure to symptoms. If subjects had difficulty in recalling first presentation to a doctor for dyspepsia, the interviewer used questions relating to landmark events as a prompt, for example: ‘Did it occur before or after you were married?’, a technique shown to improve recall of information.30, 32, 33

To examine differences between the four consulting groups, ANOVAS were performed. When the result was significant a Duncan’s range test was applied to determine which group means differed significantly. When it was only appropriate to compare two groups, t-tests or χ2-analyses were used.

RESULTS

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. MATERIALS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. Acknowledgements
  8. Bibliography

Prevalence of dyspepsia

The prevalence of dyspepsia in NSW was 32.5% (95% CI: 30.6–34.4, n=748). No significant difference was found between prevalence rates for men and women.

Consultation patterns and rates

Information regarding health consultations for dyspepsia enabled respondents to be categorized into four consulting groups. The largest group, group NO (No consultation), consisted of those who had not consulted any health practitioners for their dyspepsia (37%, n=277). Just over a third of respondents only consulted medical practitioners, group M (medical only) (34%, n=254). Members of the smallest group, group N (non-medical only), only consulted non-medical practitioners (7%, n=49). Group M + N consisted of the 22% (n=168) of subjects who had consulted both medical and non-medical practitioners for dyspepsia.

Overall, a total of 56% of respondents (n=422) (95% CI: 52.8–60.0) had ‘ever’ consulted a medical practitioner for dyspepsia. The majority (54%) of ‘ever’ consulters had consulted within 6 months of first experiencing symptoms and 78% had consulted within 3 years. Only 10% waited longer than 10 years before seeking care (Figure 1). The variable ‘time before first consultation’ was subdivided into four (< 1 week–1 month, > 1 month–1 year, > 1 year–3 years, > 3 years). Patients in groups M and M + N consulted a doctor at similar times of symptom duration (χ2=2.67, d.f.=3, P > 0.05). A total of 20% (n=150) (95% CI: 17.1–22.9) of dyspeptics had consulted a medical practitioner about their dyspepsia in the last 3 months. Recent medical consultation rates for groups M and M + N did not differ significantly (χ2=1.22, d.f.=1, P > 0.05).

image

Figure 1. Duration of dyspepsia at first medical consultation (n=394).

Download figure to PowerPoint

Twenty-nine percent (n=217; 95% CI: 25.7–32.3) of all dyspepsia cases had consulted non-medical practitioners from one or more professions. Pharmacists were the non-medical practitioners most frequently consulted (15%, n=110), followed by naturopaths (13%, n=94), dietitians/nutritionists (6%, n=45), chiropractors/osteopaths (4%, n=29), iridologists (3%, n=24), acupuncturists (3%, n=22), homoeopaths (2%, n=16) and community nurses (2%, n=16). For people who consulted a non-medical practitioner, the average number of practitioner groups consulted was 1.6. Members of group M + N consulted non-medical practitioners from a significantly greater number of professions (mean=1.7) than did members of group N (mean=1.4, t=2.01, d.f.=215, P < 0.01). χ2-analyses were performed to examine whether dyspeptics in group N or Group M + N were more likely to consult non-medical practitioners from particular professions. Subjects from both groups were as likely to consult pharmacists (χ2=0.04, d.f.=1, P > 0.05), naturopaths (χ2=0.26, d.f.=1, P > 0.05), chiropractors/osteopaths (χ2=2.87, d.f.=1, P > 0.05), iridologists (χ2=1.34, d.f.=1, P > 0.05), dieticians/nutritionists (χ2=1.60, d.f.=1, P > 0.05) and acupuncturists (χ2=0.05, d.f.=2, P > 0.05) about their dyspepsia. The numbers consulting the other non-medical groups were too small to carry out valid comparisons.

Age and sex

The mean age of the total sample was 43.7 years (s.d.=17.8). The ANOVA comparing the ages of people with the four consulting patterns indicated that these differed significantly, as shown in Table 1. Dyspeptics who consulted doctors, groups M and M + N, were significantly older than those in groups NO and N. The latter two groups did not differ significantly in age from each other. There were no significant differences in the gender composition of the four consulting groups (χ2=0.63, d.f.=3, P > 0.05).

Table 1. ANOVAs and Duncan range tests for characteristics on which the four consulting groups differed significantlyThumbnail image of

Satisfaction with medical care

Of dyspeptics who had ‘ever’ consulted a medical practitioner for dyspepsia, 27% reported that they were very satisfied with the management of their condition; 58% were satisfied, 11% were dissatisfied and 3% were very dissatisfied with their care. People in group M + N were significantly less satisfied with their medical care compared to those in group M, who consulted only medical practitioners (21% dissatisfied vs. 10%, χ2=9.37, d.f.=1, P < 0.01).

Dyspepsia symptoms

The average number of symptoms reported by the total sample of dyspeptics was 1.6 (s.d.=1.0). When the four consulting groups were compared using ANOVA, dyspeptics in group M + N reported significantly more symptoms than any other group. Dyspeptics in group NO had significantly fewer symptoms than all other groups (Table 1). Those who consulted only medical or only non-medical practitioners reported a similar number of symptoms. The average symptom severity score of the total sample was 3.2 (s.d.=0.76). The mean symptom severity of the four groups revealed no significant differences (F=1.15, d.f.=3, 743, P > 0.05).

Health status

The mean PCS score for the total sample was 47.1 (s.d.=10.2), indicating that people with dyspepsia had significantly poorer physical health than the norm (PCS=50). Dyspeptics who did not consult or who only consulted non-medical practitioners had significantly better physical health status than those in groups M and M + N (Table 1).

The mean MCS score for the total sample was 46.1 (s.d.=10.9), which was also significantly below the norm (MCS=50). Comparison of the MCS scores of the four consulting groups revealed that dyspeptics in group M had significantly better mental health than those who consulted both medical and non-medical practitioners (group M + N), or only non-medical practitioners (group N). The MCS scores of dyspeptics who did not consult (NO) did not differ significantly from those of the other three consulting groups (Table 1).

DISCUSSION

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. MATERIALS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. Acknowledgements
  8. Bibliography

The results provide a profile of the characteristics and consulting behaviour of dyspeptics in Australia. The majority (56%) consulted a medical practitioner at some time for their dyspepsia. This result is in keeping with a general trend of high medical consultation rates by Australians for gastrointestinal conditions, overall.34, 35 Population studies in Britain and Sweden, which were similar in design to the present study, found lower ‘ever’ dyspepsia consulting rates of 42% and 45%, respectively.8, 36 Three UK population studies found that 25% of dyspeptics had consulted a medical practitioner in the previous 6 months.6, 7, 9 This is similar to our 3-month ‘recent’ consulting rate of 20%. Penston et al. reported that 22% of their British sample had consulted for dyspepsia in the previous year.8‘Ever’ consulting rates provide an indication of the incidence of consulting for dyspepsia. Thus the present results show that Australians are more likely than Swedish and British dyspeptics to consult at least once for dyspepsia. ‘Recent’ consulting rates provide a measure of the prevalence of consulting for dyspepsia as both first time and repeat consulters are included. Therefore, British dyspeptics appear slightly more likely than Australians to consult repeatedly for dyspepsia.6, 7, 9 Swedish dyspeptics with a reported recent consulting rate of only 5%, appear considerably less likely to repeatedly consult compared to Australians with dyspepsia.36

A key issue in relation to consulting behaviour is how long people with dyspepsia wait before consulting a medical practitioner. The majority (78%) of the current sample consulted within 3 years of first experiencing symptoms, most (54%) within 6 months. In a Finnish sample, 60% of dyspeptics who consulted a general practitioner did so within 4 weeks of experiencing symptoms, a considerably greater percentage than the 26% of dyspeptics in the current study who consulted within 1 month of symptom onset.37

Nearly one in three Australian dyspeptics sought advice from non-medical practitioners. No known research has examined the extent to which people with dyspepsia consult such practitioners. Around 8% of patients attending a Canadian gastroenterology out-patient clinic reported attending an alternative practitioner within the previous 2 years.18, 19 Only 2% of a British sample with organic upper gastrointestinal disorders had consulted an alternative health provider.38 It has been shown that consultations with alternative practitioners often occur in association with medical consultation.39, 40 Over one third of British people who consulted alternative practitioners in 1980/81 were simultaneously seeking advice from medical practitioners for the same problem.39 In the present study, the majority of dyspeptics who consulted a non-medical health practitioner also consulted a medical practitioner about their dyspepsia. It is likely that many doctors are unaware that patients are consulting other practitioners as patients are reluctant to divulge such information to their doctor.41 Few dyspeptics in this study sought care only from a non-medical practitioner.

The results identified the characteristics of dyspeptics who had adopted the four patterns of consulting behaviours. The most common patterns were not to consult (37%) or only to consult medical practitioners (34%). Compared to dyspeptics in all, or most other consulting groups, those who had only consulted doctors tended to be older, have a moderate number of symptoms, have poorer overall physical health but better mental health and be more satisfied with their medical care. Subjects who had consulted both types of practitioners were similar to those who had consulted only doctors, in their poor physical health. They had the highest number of symptoms of any group, poorer mental health than group M and were more dissatisfied with their medical care. These last three factors probably contributed to their decision to seek non-medical care, although it is impossible to say which were causes or effects and for which subjects. The dissatisfaction which group M + N members expressed about their medical management was not reflected in the timing of either their initial or recent medical consultations, which were no different than those of group M. Consultation with the two types of practitioners seems to have occurred concurrently, although further investigation is needed as to the inter-relationships of multiple consultations. Overall, poor physical health as measured by the SF12 and number of dyspepsia symptoms, is associated with consultation with a medical practitioner, although the average severity of symptoms, an imprecise measure of total discomfort which a dyspeptic is experiencing, does not.

Dyspeptics who only sought non-medical care tended to be younger and have better overall physical health than groups M and M + N. They had fewer symptoms than group M + N, but more than those who did not consult. Non-medical consulters’ mental health was poorer than those in group M. Their overall physical health, which was better than that of groups M and M + N, may have contributed to their not seeking medical care. However, their psychological symptoms (as suggested by their poorer mental health) may have led them to regard non-medical care as more appropriate. People in group M + N consulted more types of non-medical health practitioner than did those in group N. There was no evidence that group N favoured more alternative type practitioners, such as naturopaths, or that group M + N preferred practitioners from professions more allied to medicine, such as pharmacists.

Those who did not consult resembled those who consulted non-medical practitioners only in their younger age and better physical health. Their mental health status did not differ significantly from that of any of the other groups and they had fewer dyspepsia symptoms than all other groups. Their failure to consult may be largely due to the fact that they did not have as many dyspepsia symptoms as groups M and M + N and that they had better physical health than was the case in groups M and M + N. Both groups N and NO may change their consulting behaviour over time. A prospective study of people with dyspepsia could examine the history of their consulting behaviour.

The results of a 1981 British survey of alternative health practitioners supported the stereotype of young people and women as those who seek alternative health care.39 In that survey, alternative practitioners reported that two-thirds of their patients were young or middle-aged women.39 In the current study, dyspeptics who consulted both medical and non-medical practitioners (group M + N) were of similar age and sex to those who only consulted doctors. However, the small group N comprised the youngest group in our study. Verhoef et al., in their study of gastrointestinal out-patients, found no significant differences in socio-demographic factors or health status in those who had consulted alternative practitioners and those who had not done so.18 That study did not separate alternative consulters into those who consulted these practitioners alone and those who also consulted a medical practitioner, which may explain their failure to observe differences apparent in the present study.

Little is known about the effectiveness or otherwise of alternative therapies in treating dyspepsia symptoms. There is randomized controlled trial evidence that acupuncture produces a significant decrease in sham feeding stimulated acid output.42 Yet such evidence of the effectiveness of acupuncture to accelerate ulcer healing is not available.43 As more and more patients seek out alternative health care, investigation into the potential benefits of such treatments is warranted. There also needs to be investigation into why dyspeptics decide to consult practitioners of all types. What help do they consider they receive from non-medical practitioners? How satisfied are they with the help they receive? Will they have ongoing consultations with these practitioners? It may be that while alternative practitioners are not able to offer more effective treatments for patients’ symptoms, their holistic approach, including listening to, validating and addressing patients’ concerns about their symptoms and the impact that these have on patients’ quality of life, is of therapeutic value.

Acknowledgements

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. MATERIALS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. Acknowledgements
  8. Bibliography

Financial support for this study was provided by The University of Sydney.

Bibliography

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. MATERIALS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. Acknowledgements
  8. Bibliography
  • 1
    Kay L & Jorgensen T. Epidemiology of upper dyspepsia in a random population: prevalence, incidence, natural history, and risk factors. Scand J Gastroenterol 1994; 29: 16.
  • 2
    Agreus L, Svardsudd K & Nyren O, et al. Irritable bowel syndrome and dyspepsia in the general population: overlap and lack of stability over time. Gastroenterology 1995; 109: 67180.
  • 3
    Kay L. Prevalence, incidence and prognosis of gastrointestinal symptoms in a random sample of an elderly population. Age Ageing 1994; 23: 1469.
  • 4
    Bernersen B, Johnsen R & Straume B. Non-ulcer dyspepsia and peptic ulcer: the distribution in a population and their relation to risk factors. Gut 1996; 38: 8225.
  • 5
    Agreus L, Svardsudd K & Nyren O, et al. The epidemiology of abdominal symptoms: prevalence and demographic characteristics in a Swedish adult population. Scand J Gastroenterol 1994; 29: 1029.
  • 6
    Jones RH, Lydeard SE & Hobbs FDR, et al. Dyspepsia in England and Scotland. Gut 1990; 31: 4015.
  • 7
    Jones R & Lydeard S. Prevalence of symptoms of dyspepsia in the community. Br Med J 1989; 298: 302.
  • 8
    Penston JG & Pounder RE. A survey of dyspepsia in Great Britain. Aliment Pharmacol Ther 1996; 10: 839.
  • 9
    Jones R & Lydeard S. Dyspepsia in the community: a follow-up study. Br J Clin Prac 1992; 46: 957.
  • 10
    Talley NJ, Zinsmeister AR & Schleck CD, et al. Smoking, alcohol, and analgesics in dyspepsia and among dyspepsia subgroups: lack of an association in a community. Gut 1994; 35: 61924.
  • 11
    Talley NJ, Evans JM & Fleming KC, et al. Nonsteroidal antiinflammatory drugs and dyspepsia in the elderly. Dig Dis Sci 1995; 40: 134550.
  • 12
    Holtmann G, Goebell H & Talley N. Dyspepsia in consulters and non-consulters: Prevalence, health-care seeking behaviour and risk factors. Eur J Gastroenterol Hepatol 1994; 6: 91724.
  • 13
    Talley NJ, Zinsmeister AR & Schleck CD, et al. Dyspepsia and dyspepsia subgroups: a population-based study. Gastroenterology 1992; 102: 125968.
  • 14
    Lydeard S & Jones R. Factors affecting the decision to consult with dyspepsia: comparison of consulters and non-consulters. J R Coll Gen Pract 1989; 39: 4958.
  • 15
    Johannessen T, Petersen H & Kleveland PM, et al. The predictive value of history in dyspepsia. Scand J Gastroenterol 1990; 25: 68997.
  • 16
    Talley N, Boyce P & Jones M. Dyspepsia and health care seeking in a community: How important are psychological factors? Dig Dis Sci 1998; 43: 101622.
  • 17
    Howell S & Talley N. Does fear of serious disease predict consulting behaviour amongst patients with dyspepsia in general practice? European J Gastroenterol Hepatol 1999; 11: 8816.
  • 18
    Verhoef M, Sutherland L & Brkich L. Use of alternative medicine by patients attending a gastroenterology clinic. Can Med Assoc J 1990; 142: 1215.
  • 19
    Sutherland L & Verhoef M. Why do patients seek a second opinion or alternative medicine? J Clin Gastroenterol 1994; 19: 1947.
  • 20
    Talley NJ, Colin-Jones D & Koch KL, et al. Functional dyspepsia: a classification with guidelines for diagnosis and management. Gastroenterol Int 1991; 4: 14560.
  • 21
    Veldhuyzen van Zanten SJO, Tytgat KMAJ & Pollak PT, et al. Can severity of symptoms be used as an outcome measure in trials of non-ulcer dyspepsia and Helicobacter pylori associated gastritis? J Clin Epidemiol 1993; 46: 2739.
  • 22
    Kuykendall D, Rabeneck L & Campbell C, et al. Dyspepsia: How should we measure it? J Clin Epidemiol 1998; 51: 99106.DOI: 10.1016/s0895-4356(97)00245-x
  • 23
    Ware J, Kosinski M & Keller S. A 12-item short-form health survey: Construction of scales and preliminary test of reliability and validity. Med Care 1996; 34: 22033.
  • 24
    Dwyer J, Gardner J & Halvorsen K, et al. Memory of food intake in the distant past. Am J Epidemiol 1989; 130: 103345.
  • 25
    Bourbonnais R, Meyer T & Theriault G. Validity of self reported work history. Br J Ind Med 1988; 45: 2932.
  • 26
    Stewart M, Tonascia J & Matanoski G. The validity of questionnaire-reported work history in live respondents. J Occ Med 1987; 29: 795800.
  • 27
    Must A, Willett WC & Dietz WH. Remote recall of childhood height, weight, and body build by elderly subjects. Am J Epidemiol 1993; 138: 5664.
  • 28
    Casey VA, Dwyer JT & Berkey CS, et al. Long-term memory of body weight and past weight satisfaction: a longitudinal follow-up study. Am J Clin Nutrition 1991; 53: 14938.
  • 29
    Field D. Retrospective reports by healthy intelligent elderly people of personal events of their adult lives. Int J Behav Dev 1981; 4: 7797.
  • 30
    Berney LR & Blane DB. Collecting retrospective data: accuracy of recall after 50 years judged against historical records. Soc Sci Med 1997; 45: 151925.DOI: 10.1016/s0277-9536(97)00088-9
  • 31
    Baumgarten M, Siemiatycki J & Gibbs GW. Validity of work histories obtained by interview for epidemiological purposes. Am J Epidemiol 1983; 118: 58391.
  • 32
    Bradburn NM, Rips LJ & Shevell SK. Answering autobiographical questions: the impact of memory and inference on surveys. Science 1987; 236: 15761.
  • 33
    Blane DB. Collecting retrospective data: development of a reliable method and a pilot study of its use. Soc Sci Med 1996; 42: 7517.DOI: 10.1016/0277-9536(95)00340-1
  • 34
    Talley N, Boyce P & Jones M. Predictors of health care seeking for irritable bowel syndrome: a population based study. Gut 1997; 41: 4156.
  • 35
    Byles J, Redman S & Hennrikus D, et al. Delay in consulting a medical practitioner about rectal bleeding. J Epidemiol Comm Health 1992; 46: 2414.
  • 36
    Agreus L. Socio-economic factors, health care consumption and rating of abdominal symptom severity. A report from the abdominal symptom study. Fam Pract 1993; 10: 15263.
  • 37
    Heikkinen M, Pikkarainen P & Takala J, et al. General practitioners’ approach to dyspepsia: Survey of consultation frequencies, treatment, and investigations. Scand J Gastroenterol 1996; 31: 64853.
  • 38
    Smart H, Mayberry J & Atkinson M. Alternative medicine consultations and remedies in patients with the irritable bowel syndrome. Gut 1986; 27: 8268.
  • 39
    Fulder SJ & Munro RE. Complementary medicine in the United Kingdom: patients, practitioners, and consultations. Lancet 1985; 2: 5425.
  • 40
    Clinical Oncology Group. New Zealand cancer patients and alternative medicine. N Z Med J 1987; 100: 11013.
  • 41
    Strauss A. Chronic Illness and the Quality of Life. St Louis: Mosby, 1984.
  • 42
    Tougas G, Yuan L & Radamaker J, et al. Effect of acupuncture on gastric acid secretion in healthy male volunteers. Dig Dis Sci 1992; 37: 157682.
  • 43
    Tougas G & Hunt R. Relation of acupuncture and vagal gastric acid secretion. Gut 1995; 36: 8001.