title: Reproducibility and validity of a postal questionnaire. The abdominal symptom study.
abstract: OBJECTIVE
  To find out whether it is possible to examine abdominal/gastrointestinal symptoms by a postal questionnaire.
  
  
  METHODS
  In the Abdominal Symptom Study a postal questionnaire was sent to a representative sample of adults (n = 1290) on two occasions, one year apart. The questionnaire was sent a third time to a subsample (n = 110), and to another sample (n = 213) who had not seen the questionnaire before. A subsample (n = 150 of the 1290) was subjected to a medical interview and examination.
  
  
  METHODS
  The municipality of Osthammar, Sweden.
  
  
  METHODS
  A sample (9.3%) of all Swedish citizens (20-79 yrs) in the municipality.
  
  
  METHODS
  Reproducibility and validity of a postal questionnaire.
  
  
  RESULTS
  The response rate was 90%. Roughly 50% of the study population reported abdominal symptoms. The reproducibility of the results was satisfactory, as was the validity of the questionnaire evaluated by medical interview and examination. Non-responders did not report more symptoms than responders.
  
  
  CONCLUSIONS
  It is possible to examine abdominal/gastrointestinal symptoms with a postal questionnaire. The questionnaire used in The Abdominal Symptom Study seems to be useful for this purpose.
authors.affiliation: Uppsala University, Department of Family Medicine, Sweden.
authors.forename: L
authors.initials: L
authors.lastname: Agréus
authors.forename: K
authors.initials: K
authors.lastname: Svärdsudd
authors.forename: O
authors.initials: O
authors.lastname: Nyrén
authors.forename: G
authors.initials: G
authors.lastname: Tibblin
mesh_terms: D015746:Abdominal Pain / Q000175:diagnosis* / Q000453:epidemiology*; D000328:Adult; D005260:Female; D005767:Gastrointestinal Diseases / Q000175:diagnosis* / Q000453:epidemiology*; D006801:Humans; D008297:Male; D008487:Medical History Taking; D010808:Physical Examination; D011159:Population Surveillance / Q000379:methods*; D015995:Prevalence; D015203:Reproducibility of Results; D012494:Sampling Studies; D012680:Sensitivity and Specificity; D011795:Surveys and Questionnaires / Q000592:standards*; D013548:Sweden / Q000453:epidemiology