title: Cord blood vitamin D status and neonatal outcomes in a birth cohort in Quebec, Canada.
abstract: OBJECTIVE
  Some evidence suggests that low maternal vitamin D status adversely affects perinatal health but few studies have examined cord blood vitamin D status. This project aimed to determine the association between the cord blood concentration of 25-hydroxyvitamin D [25(OH)D] and neonatal outcomes.
  
  
  METHODS
  A nested case-control study was conducted in Quebec City, Canada from 2005 to 2010. Included were 83 cases of low birthweight (LBW; <2500 g), 301 cases of small for gestational age (SGA; <10th percentile), 223 cases of preterm birth (PTB; <37 weeks' gestation), and 1027 controls. Levels of 25(OH)D were determined by chemiluminescence immunoassay. Adjusted odds ratios (OR) and 95 % confidence intervals (CI) were estimated with logistic regression.
  
  
  RESULTS
  Cord blood [25(OH)D] <50 nmol/L was associated with a lower risk of LBW compared to [25(OH)D] ≥75 nmol/L (OR 0.47 95 % CI 0.23-0.97). For 25(OH)D levels 50-75 nmol/L, a significant association was not demonstrated (OR 0.58, 95 % CI 0.34-1.01). No significant associations were observed between [25(OH)D] and either SGA or PTB after adjustment.
  
  
  CONCLUSIONS
  Although our findings suggest that [25(OH)D] <50 nmol/L is associated with reduced risk of having a LBW infant, prenatal vitamin D recommendations require an examination of the literature that considers the full spectrum of maternal and neonatal outcomes.
authors.affiliation: Department of Community Health and Epidemiology, Centre for Clinical Research, Dalhousie University, 5790 University Avenue, Halifax, NS, B3H 1V7, Canada.
authors.forename: Catherine
authors.initials: C
authors.lastname: Morgan
authors.affiliation: Departments of Obstetrics and Gynaecology and Pediatrics, Dalhousie University, 5980 University Avenue, PO Box 9700, Halifax, NS, B3K 6R8, Canada.
authors.forename: Linda
authors.initials: L
authors.lastname: Dodds
authors.affiliation: Department of Community Health and Epidemiology, Centre for Clinical Research, Dalhousie University, 5790 University Avenue, Halifax, NS, B3H 1V7, Canada.
authors.forename: Donald B
authors.initials: DB
authors.lastname: Langille
authors.affiliation: School of Dietetics and Human Nutrition, McGill University, Macdonald Campus, MS2042a Macdonald Stewart Bldg, 21111 Lakeshore Rd, Ste. Anne de Bellevue, Quebec, H9X 3V9, Canada.
authors.forename: Hope A
authors.initials: HA
authors.lastname: Weiler
authors.affiliation: Department of Obstetrics and Gynaecology, Dalhousie University, 5980 University Avenue, PO Box 9700, Halifax, NS, B3K 6R8, Canada.
authors.forename: B Anthony
authors.initials: BA
authors.lastname: Armson
authors.affiliation: Department of Molecular Biology, Medical Biochemistry and Pathology, Centre Hospitalier Universitaire de Québec Research Centre, Université Laval, 10, rue de l'Espinay, Quebec, QC, G1L 3L5, Canada.
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Forest
authors.affiliation: Department of Molecular Biology, Medical Biochemistry and Pathology, Centre Hospitalier Universitaire de Québec Research Centre, Université Laval, 10, rue de l'Espinay, Quebec, QC, G1L 3L5, Canada.
authors.forename: Yves
authors.initials: Y
authors.lastname: Giguère
authors.affiliation: Departments of Obstetrics and Gynaecology and Pediatrics, Dalhousie University, 5980 University Avenue, PO Box 9700, Halifax, NS, B3K 6R8, Canada. christy.woolcott@dal.ca.
authors.forename: Christy G
authors.identifier: http://orcid.org/0000-0002-4606-3125
authors.initials: CG
authors.lastname: Woolcott
mesh_terms: D015415:Biomarkers / Q000097:blood; D002170:Canada; D016022:Case-Control Studies; D005260:Female; D005312:Fetal Blood / Q000378:metabolism*; D005865:Gestational Age; D006801:Humans; D007223:Infant; D007230:Infant, Low Birth Weight / Q000097:blood; D007231:Infant, Newborn; D007236:Infant, Small for Gestational Age / Q000097:blood*; D016015:Logistic Models; D008297:Male; D016017:Odds Ratio; D011247:Pregnancy; D047928:Premature Birth / Q000097:blood; D011792:Quebec; D012307:Risk Factors; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood*; D014815:Vitamins / Q000097:blood*
chemical_list: D015415:Biomarkers; D014815:Vitamins; D014807:Vitamin D; C104450:25-hydroxyvitamin D
keywords: 25-Hydroxyvitamin D; Low birth weight; Nested case–control study; Preterm birth; Small for gestational age