title: Prevalence and predictors of vitamin D insufficiency in women of reproductive age living in northern latitude.
abstract: OBJECTIVE
  This study assessed the prevalence of vitamin D deficiency (serum 25-hydroxyvitamin D (25OHD) ≤ 50 nmol/l) and insufficiency (serum 25OHD 51-74 nmol/l) during summer and the predictors of serum 25OHD in young women of reproductive age.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  Between May and September 2006, 153 healthy, ambulatory and essentially Caucasian women, aged 18-41 years, were recruited. Serum 25OHD and parathyroid hormone (PTH) levels were measured, and questionnaires were evaluated.
  
  
  RESULTS
  About 3.9% of women had serum 25OHD ≤ 50 nmol/l with an additional 26.8% in the insufficient range. Most women (56.9%) had their blood sampled in September. Month of blood collection significantly influenced serum 25OHD. Body mass index (BMI) was inversely associated with serum 25OHD, while traveling to a warmer climate during winter/spring and using oral contraceptive pills (OCP) were associated with higher serum 25OHD. Sunscreen was used by 77.8% of women, but only 3.3% reported consuming vitamin D supplements. BMI, serum PTH, travel to a warmer climate, and OCP use were independently and significantly associated with serum 25OHD, after adjustment for the month of sampling, and explained 40% of the variance in serum 25OHD.
  
  
  CONCLUSIONS
  In Canada, the prevalence of vitamin D insufficiency is relatively high (30%) during summer in healthy women of reproductive age. Given the expected decrease in serum 25OHD during winter and the low consumption of vitamin D supplements, a high prevalence of vitamin D deficiency and insufficiency is to be anticipated during winter, except maybe for those traveling to a warmer climate.
authors.affiliation: Division of Endocrinology, Department of Medicine, Université de Sherbrooke, 12th Avenue North, Fleurimont, Québec, Canada.
authors.forename: Claudia
authors.initials: C
authors.lastname: Gagnon
authors.forename: Jean-Patrice
authors.initials: JP
authors.lastname: Baillargeon
authors.forename: Guillaume
authors.initials: G
authors.lastname: Desmarais
authors.forename: Guy D
authors.initials: GD
authors.lastname: Fink
mesh_terms: D000293:Adolescent; D000328:Adult; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D011237:Predictive Value of Tests; D015995:Prevalence; D011792:Quebec / Q000453:epidemiology; D012098:Reproduction / Q000502:physiology*; D012621:Seasons; D011795:Surveys and Questionnaires; D014807:Vitamin D / Q000097:blood*; D014808:Vitamin D Deficiency / Q000097:blood* / Q000175:diagnosis / Q000453:epidemiology*; D055815:Young Adult
chemical_list: D014807:Vitamin D