title: Use of a questionnaire to assess vitamin D status in young adults.
abstract: OBJECTIVE
  We hypothesized that young adults would commonly have vitamin D deficiency and that a questionnaire could help identify subjects with the condition.
  
  
  METHODS
  Between January and May 2004, we administered a questionnaire to a convenience sample of young adults. We measured each participant's serum level of 25-hydroxyvitamin D (25(OH)D) using a chemiluminescent assay and defined deficiency as serum 25(OH)D < 16 ng/ml.
  
  
  METHODS
  We recruited young adults living in Madison, Wisconsin without pre-existing conditions affecting vitamin D and/or Ca metabolism.
  
  
  RESULTS
  One hundred and eighty-four adults (mean age 24 years, 53 % women, 90 % Caucasian) participated in the study. Nearly three in four adults (71 %) had 25(OH)D level <30 ng/ml and 26 % were vitamin D-deficient. In multivariate analysis, persons reporting a suntan (OR = 0.24, 95 % CI 0.09, 0.63, P = 0.004), tanning booth use (OR = 0.09, 95 % CI 0.02, 0.43, P = 0.002) and daily ingestion of two or more servings of milk (OR = 0.21, 95 % CI 0.09, 0.48, P < 0.001) were less likely to be deficient. These three questions provided a sensitivity and specificity of 79 % and 78 %, respectively, for the presence of deficiency.
  
  
  CONCLUSIONS
  The questionnaire is moderately useful to identify young adults likely to be vitamin D-deficient. Additional revisions of the questionnaire may improve its ability to predict vitamin D deficiency.
authors.affiliation: Department of Medicine, University of Wisconsin School of Medicine & Public Health, Madison, WI, USA. Jbolek-berquist@uwealth.org
authors.forename: Jilaine
authors.initials: J
authors.lastname: Bolek-Berquist
authors.forename: Mary E
authors.initials: ME
authors.lastname: Elliott
authors.forename: Ronald E
authors.initials: RE
authors.lastname: Gangnon
authors.forename: Dessa
authors.initials: D
authors.lastname: Gemar
authors.forename: Jean
authors.initials: J
authors.lastname: Engelke
authors.forename: Susan J
authors.initials: SJ
authors.lastname: Lawrence
authors.forename: Karen E
authors.initials: KE
authors.lastname: Hansen