title: Prevalence and predictors of vitamin D deficiency in healthy adults.
abstract: OBJECTIVE
  Vitamin D deficiency is highly prevalent in high-risk patient populations, but the prevalence among otherwise healthy adults is less well-defined. The goal of this study was to determine the prevalence and predictors of low 25-hydroxyvitamin D [25(OH)D] levels in healthy younger adults.
  
  
  METHODS
  This was a cross-sectional study of 634 healthy volunteers aged 18-50 years performed between January, 2006 and May, 2008. We measured serum 25(OH)D and parathyroid hormone and recorded demographic variables including age, sex, race, and use of multivitamin supplements.
  
  
  RESULTS
  Thirty-nine percent of subjects had 25(OH)D ≤ 20 ng/mL and 64% had 25(OH)D ≤ 30 ng/mL. Predictors of lower 25(OH)D levels included male sex, black or Asian race, and lack of multivitamin use (P<0.001 for each predictor). Seasonal variation in 25(OH)D levels was present in the overall cohort but was not observed in multivitamin users. Lower 25(OH)D levels were associated with increased risk of elevated parathyroid hormone. Regression models predicted 25(OH)D levels ≤ 20 or ≤ 30 ng/mL with areas under the receiver operating characteristic curves of 0.76 and 0.80, respectively.
  
  
  CONCLUSIONS
  Low 25(OH)D levels are prevalent in healthy adults and may confer risk of skeletal disease. Black and Asian adults are at increased risk of deficiency and multivitamin use appears partially protective. Our models predicting low 25(OH)D levels may guide decision-making regarding whom to screen for vitamin D deficiency.
authors.affiliation: Endocrine Unit, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts 02114, USA. dmmitchell@partners.org
authors.forename: Deborah M
authors.initials: DM
authors.lastname: Mitchell
authors.forename: Maria P
authors.initials: MP
authors.lastname: Henao
authors.forename: Joel S
authors.initials: JS
authors.lastname: Finkelstein
authors.forename: Sherri-Ann M
authors.initials: SA
authors.lastname: Burnett-Bowie
mesh_terms: D000293:Adolescent; D000328:Adult; D044466:Asian People / Q000208:ethnology*; D044383:Black People / Q000208:ethnology*; D003430:Cross-Sectional Studies; D019587:Dietary Supplements; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood; D011237:Predictive Value of Tests; D015995:Prevalence; D012307:Risk Factors; D012621:Seasons; D012737:Sex Factors; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood / Q000453:epidemiology* / Q000208:ethnology*; D014815:Vitamins / Q000008:administration & dosage; D055815:Young Adult
chemical_list: D010281:Parathyroid Hormone; D014815:Vitamins; D014807:Vitamin D; C104450:25-hydroxyvitamin D