title: Sensitivity and specificity of self-reported use of dietary supplements.
abstract: OBJECTIVE
  To evaluate the sensitivity and specificity of a self-administered food frequency questionnaire (FFQ)-used in a cohort of 48,000 men to determine dietary supplement use.
  
  
  METHODS
  Questionnaire data regarding use of dietary supplements were compared with 14 24-h recall interviews spread over a year.
  
  
  METHODS
  A random sample of 248 middle-aged and elderly Swedish men was included in the analysis.
  
  
  CONCLUSIONS
  Use of any supplement in at least one interview was reported by 51% (in three or more interviews by 38%). Sensitivity and specificity of the FFQ regarding any supplement use was 78 and 93%, respectively. Sensitivity for multivitamins, vitamins C and E was 69, 67 and 78%, respectively. The sensitivity increased to 93% and the specificity decreased to 88% when a user was defined as a person reporting use in at least three interviews.
  
  
  CONCLUSIONS
  Dietary supplement use might be measured by a self-administered questionnaire relatively well especially when supplements are used more regularly.
authors.affiliation: Department of Nutritional Epidemiology, National Institute of Environmental Medicine, Stockholm, Sweden. maria.messerer@imm.ki.se
authors.forename: M
authors.initials: M
authors.lastname: Messerer
authors.forename: A
authors.initials: A
authors.lastname: Wolk
mesh_terms: D000328:Adult; D000368:Aged; D015331:Cohort Studies; D019587:Dietary Supplements / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D011939:Mental Recall; D008875:Middle Aged; D011237:Predictive Value of Tests; D012650:Self Disclosure; D012680:Sensitivity and Specificity; D011795:Surveys and Questionnaires / Q000592:standards*; D014815:Vitamins / Q000008:administration & dosage*
chemical_list: D014815:Vitamins