title: Suboptimal vitamin D levels in pregnant women despite supplement use.
abstract: OBJECTIVE
  Obtaining adequate vitamin D during pregnancy is important for the health of mother and child. Low circulating 25-hydroxyvitamin D (25OHD) concentrations, a measure of vitamin D status, have been reported in pregnant women in several countries; yet, there are few studies of pregnant Canadian women. We measured 25OHD concentrations in a multi-ethnic group of pregnant women living in Vancouver (49 degrees N) and explored the determinants of 25OHD.
  
  
  METHODS
  336 pregnant women (16-47 y) between 20 and 35 weeks gestation provided a blood sample and completed questionnaires.
  
  
  RESULTS
  Mean 25OHD was 67 (95% CI 64-69) nmol/L. Only 1% of women had a 25OHD concentration indicative of severe deficiency (<25 nmol/L). However, 24% and 65% of women were vitamin D insufficient based on cut-offs of 50 and 75 nmol/L, respectively. In multivariate analysis, mean 25OHD concentrations were 12 nmol/L higher in the summer compared to in winter. Women of European (White) ethnicity had a 9-13 nmol/L higher mean 25OHD concentration than women from other ethnic groups. Almost 80% of women took vitamin D-containing supplements containing > or = 400 IU/d. However, 24% and 65% of these women had 25OHD <50 and <75 nmol/L, respectively.
  
  
  CONCLUSIONS
  Vitamin D insufficiency was not uncommon in this group of pregnant women. Season and ethnicity were determinants of 25OHD but the magnitude of their effect was not large. Most women took vitamin D-containing supplements but this did not provide much protection against insufficiency. Consideration should be given to increasing the amount of vitamin D in prenatal supplements.
authors.affiliation: Department of Food, Nutrition & Health, University of British Columbia, Vancouver, BC.
authors.forename: Wangyang
authors.initials: W
authors.lastname: Li
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Green
authors.forename: Sheila M
authors.initials: SM
authors.lastname: Innis
authors.forename: Susan I
authors.initials: SI
authors.lastname: Barr
authors.forename: Susan J
authors.initials: SJ
authors.lastname: Whiting
authors.forename: Antonia
authors.initials: A
authors.lastname: Shand
authors.forename: Peter
authors.initials: P
authors.lastname: von Dadelszen
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001955:British Columbia / Q000453:epidemiology; D016009:Chi-Square Distribution; D005260:Female; D006801:Humans; D011247:Pregnancy; D012307:Risk Factors; D012621:Seasons; D012880:Skin Pigmentation; D011795:Surveys and Questionnaires; D014807:Vitamin D / Q000097:blood / Q000627:therapeutic use*; D014808:Vitamin D Deficiency / Q000097:blood / Q000453:epidemiology* / Q000208:ethnology / Q000517:prevention & control
chemical_list: D014807:Vitamin D