title: Vitamin D and hypertension in pregnancy.
abstract: OBJECTIVE
  Vitamin D Deficiency is common, particularly in northern latitudes. We examined the association between vitamin D status and hypertension in late pregnancy.
  
  
  METHODS
  A case-control study was conducted during two time periods: September-October, 2008, and January-March, 2009, in women near term. A case was defined as having two or more documented blood pressure readings above 140/90 (either/or) at any time during pregnancy (n=78). Controls had at least two blood pressure readings, with none above 140/90 during pregnancy (n=109). Serum 25-hydroxyvitamin D (25(OH)D) was measured in all participants.
  
  
  RESULTS
  In the summer, 13% of controls and 29% of the cases had 25(OH) D levels < 50 nmol/L. During the winter, these numbers rose to 44% and 49% respectively. Both cases and controls were more likely to be vitamin D deficient in the winter (p=0.002). There was a negative correlation between BMI and 25(OH)D (r=-0.202, p=0.002). In univariate analysis, cases had lower 25(OH)D (p=0.046), but also higher body mass index, so that in multivariate analysis 25(OH)D status was no longer significant. There was no difference in mean oral daily vitamin D intake (dietary intake and supplements, 746 and 785 IU respectively). Controls gained less weight in pregnancy. There was a negative correlation between the highest blood pressure measured in pregnancy and 25(OH)D levels (r= -0.118; p=0.012).
  
  
  CONCLUSIONS
  There is a high prevalence of vitamin D deficiency in pregnant women recruited in Saskatoon, Saskatchewan. Women with low circulating vitamin D concentrations are more likely to have hypertension.
authors.affiliation: University of Alberta, Canada. jennifer.ringrose@ualberta.ca
authors.forename: Jennifer S
authors.initials: JS
authors.lastname: Ringrose
authors.forename: Anne M
authors.initials: AM
authors.lastname: PausJenssen
authors.forename: Merne
authors.initials: M
authors.lastname: Wilson
authors.forename: Lara
authors.initials: L
authors.lastname: Blanco
authors.forename: Heather
authors.initials: H
authors.lastname: Ward
authors.forename: Thomas W
authors.initials: TW
authors.lastname: Wilson
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D006973:Hypertension / Q000097:blood*; D007231:Infant, Newborn; D008297:Male; D011247:Pregnancy; D011249:Pregnancy Complications, Cardiovascular / Q000097:blood*; D011795:Surveys and Questionnaires; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D055815:Young Adult
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D