title: Vitamin D status in early pregnancy and risk of preeclampsia.
abstract: OBJECTIVE
  We sought to examine the association between maternal serum 25-hydroxyvitamin D (25[OH]D) concentration in early pregnancy and the subsequent diagnosis of preeclampsia (PE).
  
  
  METHODS
  This was a nested case-control study from 2 prospective Canadian cohorts conducted in Quebec City, Quebec, and Halifax, Nova Scotia, from 2002 through 2010. Participants were pregnant women (n = 169 cases with PE and 1975 controls). Maternal serum was drawn <20 weeks of gestation, and 25(OH)D measurement was performed. Cases were ascertained from medical records. Logistic regression analysis was used to estimate adjusted odds ratios with 95% confidence intervals.
  
  
  RESULTS
  Women who developed PE had a significantly lower 25(OH)D concentration at a mean gestational age of 14 weeks compared with women in the control group (mean ± SD 25[OH]D 47.2 ± 17.7 vs 52.3 ± 17.2 nmol/L, P < .0001). Women with 25(OH)D <30 nmol/L compared to those with at least 50 nmol/L had a greater risk of developing PE (adjusted odds ratio, 2.23; 95% confidence interval, 1.29-3.83) after adjustment for prepregnancy body mass index, maternal age, smoking, parity, season and year of blood collection, gestational week at blood collection, and cohort site. Exploratory analysis with cubic splines demonstrated a dose-response relationship between maternal 25(OH)D and risk of PE, up to levels around 50 nmol/L, where the association appeared to plateau.
  
  
  CONCLUSIONS
  Maternal vitamin D deficiency early in pregnancy defined as 25(OH)D <30 nmol/L may be an independent risk factor for PE. The relevance of vitamin D supplementation for women of childbearing age should be explored as a strategy for reducing PE and for promoting a healthier pregnancy.
authors.affiliation: School of Dietetics and Human Nutrition, McGill University, Ste. Anne de Bellevue, Quebec, Canada.
authors.forename: Madonna
authors.initials: M
authors.lastname: Achkar
authors.affiliation: Perinatal Epidemiology Research Unit, Dalhousie University and Izaak Walton Killam Health Centre, Halifax, Nova Scotia, Canada.
authors.forename: Linda
authors.initials: L
authors.lastname: Dodds
authors.affiliation: Centre Hospitalier Universitaire de Québec Research Center and Department of Molecular Biology, Medical Biochemistry and Pathology, Faculty of Medicine, Université Laval, Quebec City, Quebec, Canada.
authors.forename: Yves
authors.initials: Y
authors.lastname: Giguère
authors.affiliation: Centre Hospitalier Universitaire de Québec Research Center and Department of Molecular Biology, Medical Biochemistry and Pathology, Faculty of Medicine, Université Laval, Quebec City, Quebec, Canada.
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Forest
authors.affiliation: Department of Obstetrics and Gynecology, Dalhousie University and Izaak Walton Killam Health Centre, Halifax, Nova Scotia, Canada.
authors.forename: B Anthony
authors.initials: BA
authors.lastname: Armson
authors.affiliation: Perinatal Epidemiology Research Unit, Dalhousie University and Izaak Walton Killam Health Centre, Halifax, Nova Scotia, Canada.
authors.forename: Christy
authors.initials: C
authors.lastname: Woolcott
authors.affiliation: School of Dietetics and Human Nutrition, McGill University, Ste. Anne de Bellevue, Quebec, Canada.
authors.forename: Sherry
authors.initials: S
authors.lastname: Agellon
authors.affiliation: Perinatal Epidemiology Research Unit, Dalhousie University and Izaak Walton Killam Health Centre, Halifax, Nova Scotia, Canada.
authors.forename: Anne
authors.initials: A
authors.lastname: Spencer
authors.affiliation: School of Dietetics and Human Nutrition, McGill University, Ste. Anne de Bellevue, Quebec, Canada. Electronic address: hope.weiler@mcgill.ca.
authors.forename: Hope A
authors.initials: HA
authors.lastname: Weiler
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood; D002170:Canada; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D016015:Logistic Models; D016017:Odds Ratio; D011225:Pre-Eclampsia / Q000097:blood / Q000209:etiology*; D011247:Pregnancy; D011261:Pregnancy Trimester, First / Q000097:blood*; D011262:Pregnancy Trimester, Second / Q000097:blood*; D011446:Prospective Studies; D012307:Risk Factors; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood / Q000150:complications*
chemical_list: D015415:Biomarkers; D014807:Vitamin D; C104450:25-hydroxyvitamin D
keywords: 25-hydroxyvitamin D; preeclampsia; vitamin D