title: Exposure to phthalates, bisphenol A and metals in pregnancy and the association with impaired glucose tolerance and gestational diabetes mellitus: The MIREC study.
abstract: BACKGROUND
  Studies from several countries report increases in rates of gestational diabetes mellitus (GDM) over recent decades. Exposure to environmental chemicals could contribute to this trend.
  
  
  OBJECTIVE
  To determine the associations between plasticisers and metals measured in early pregnancy with impaired glucose tolerance (IGT) and GDM in a Canadian pregnancy cohort.
  
  
  METHODS
  Women enrolled in the Maternal-Infant Research on Environmental Chemicals (MIREC) Study were included if they had a singleton delivery and did not have pre-existing diabetes. Eleven phthalate metabolites and total bisphenol A (BPA) were measured in first-trimester urine samples, and four metals (lead, cadmium, mercury and arsenic) were measured in first-trimester blood samples. IGT and GDM were assessed in accordance with standard guidelines by chart review. Chemical concentrations were grouped by quartiles, and associations with outcomes were examined using logistic regression with adjustment for maternal age, race, pre-pregnancy BMI, and education. Restricted cubic spline analysis was performed to help assess linearity and nature of any dose-response relationships.
  
  
  RESULTS
  Of 2001 women recruited into the MIREC cohort, 1274 met the inclusion criteria and had outcome data and biomonitoring data measured for at least one of the chemicals we examined. Elevated odds of GDM were observed in the highest quartile of arsenic exposure (OR = 3.7, 95% CI = 1.4-9.6) in the adjusted analyses. A significant dose-response relationship was observed in a cubic spline model between arsenic and odds of GDM (p < 0.01). No statistically significant associations were observed between phthalates or BPA or other metals with IGT or GDM.
  
  
  CONCLUSIONS
  Our findings add to the growing body of evidence supporting the role of maternal arsenic exposure as a risk factor for gestational diabetes.
authors.affiliation: Department of Social and Preventive Medicine, Université de Montréal, Montréal, Quebec, Canada; CHU Sainte-Justine Research Centre, Université de Montréal, Montréal, Quebec, Canada.
authors.forename: G D
authors.initials: GD
authors.lastname: Shapiro
authors.affiliation: Dalhousie University, Halifax, Nova Scotia, Canada. Electronic address: L.Dodds@dal.ca.
authors.forename: L
authors.initials: L
authors.lastname: Dodds
authors.affiliation: Health Canada, Ottawa, Ontario, Canada.
authors.forename: T E
authors.initials: TE
authors.lastname: Arbuckle
authors.affiliation: Dalhousie University, Halifax, Nova Scotia, Canada.
authors.forename: J
authors.initials: J
authors.lastname: Ashley-Martin
authors.affiliation: CHU Sainte-Justine Research Centre, Université de Montréal, Montréal, Quebec, Canada; Department of Obstetrics and Gynecology, Université de Montréal, Montréal, Quebec, Canada.
authors.forename: W
authors.initials: W
authors.lastname: Fraser
authors.affiliation: Health Canada, Ottawa, Ontario, Canada.
authors.forename: M
authors.initials: M
authors.lastname: Fisher
authors.affiliation: University of Manitoba, Winnipeg, Manitoba, Canada.
authors.forename: S
authors.initials: S
authors.lastname: Taback
authors.affiliation: University of Ottawa, Ottawa, Ontario, Canada.
authors.forename: E
authors.initials: E
authors.lastname: Keely
authors.affiliation: CHU Sainte-Justine Research Centre, Université de Montréal, Montréal, Quebec, Canada.
authors.forename: M F
authors.initials: MF
authors.lastname: Bouchard
authors.affiliation: McGill University, Montréal, Quebec, Canada.
authors.forename: P
authors.initials: P
authors.lastname: Monnier
authors.affiliation: Laval University, Québec City, Quebec, Canada.
authors.forename: R
authors.initials: R
authors.lastname: Dallaire
authors.affiliation: CHU Sainte-Justine Research Centre, Université de Montréal, Montréal, Quebec, Canada.
authors.forename: As
authors.initials: A
authors.lastname: Morisset
authors.affiliation: Yale University, New Haven, CT, USA.
authors.forename: A S
authors.initials: AS
authors.lastname: Ettinger
mesh_terms: D000293:Adolescent; D000328:Adult; D001151:Arsenic / Q000097:blood / Q000652:urine; D001559:Benzhydryl Compounds / Q000097:blood / Q000378:metabolism* / Q000652:urine; D002170:Canada / Q000453:epidemiology; D015331:Cohort Studies; D016640:Diabetes, Gestational / Q000453:epidemiology* / Q000209:etiology; D004785:Environmental Pollutants / Q000097:blood / Q000378:metabolism* / Q000652:urine; D005260:Female; D005951:Glucose Tolerance Test; D006801:Humans; D016015:Logistic Models; D018811:Maternal Exposure; D008670:Metals / Q000097:blood / Q000378:metabolism* / Q000652:urine; D010636:Phenols / Q000097:blood / Q000378:metabolism* / Q000652:urine; D010795:Phthalic Acids / Q000097:blood / Q000378:metabolism* / Q000652:urine; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D012307:Risk Factors; D055815:Young Adult; D000098826:Bisphenol A Compounds
chemical_list: D001151:Arsenic; D001559:Benzhydryl Compounds; D004785:Environmental Pollutants; D008670:Metals; D010636:Phenols; D010795:Phthalic Acids; C006780:bisphenol A; D000098826:Bisphenol A Compounds
keywords: Arsenic; Cohort study; Gestational diabetes; Metals; Phthalates; Pregnancy