title: Preconception and early pregnancy air pollution exposures and risk of gestational diabetes mellitus.
abstract: BACKGROUND
  Air pollution has been linked to gestational diabetes mellitus (GDM) but no studies have evaluated impact of preconception and early pregnancy air pollution exposures on GDM risk.
  
  
  METHODS
  Electronic medical records provided data on 219,952 singleton deliveries to mothers with (n=11,334) and without GDM (n=208,618). Average maternal exposures to particulate matter (PM) ≤ 2.5μm (PM2.5) and PM2.5 constituents, PM ≤ 10μm (PM10), nitrogen oxides (NOx), carbon monoxide, sulfur dioxide (SO2) and ozone (O3) were estimated for the 3-month preconception window, first trimester, and gestational weeks 1-24 based on modified Community Multiscale Air Quality models for delivery hospital referral regions. Binary regression models with robust standard errors estimated relative risks (RR) for GDM per interquartile range (IQR) increase in pollutant concentrations adjusted for study site, maternal age and race/ethnicity.
  
  
  RESULTS
  Preconception maternal exposure to NOX (RR=1.09, 95% CI: 1.04, 1.13) and SO2 (RR=1.05, 1.01, 1.09) were associated with increased risk of subsequent GDM and risk estimates remained elevated for first trimester exposure. Preconception O3 was associated with lower risk of subsequent GDM (RR=0.93, 0.90, 0.96) but risks increased later in pregnancy.
  
  
  CONCLUSIONS
  Maternal exposures to NOx and SO2 preconception and during the first few weeks of pregnancy were associated with increased GDM risk. O3 appeared to increase GDM risk in association with mid-pregnancy exposure but not in earlier time windows. These common exposures merit further investigation.
authors.affiliation: Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Division of Intramural Population Health Research, Epidemiology Branch, Rockville, MD 20892, USA.
authors.forename: Candace A
authors.initials: CA
authors.lastname: Robledo
authors.affiliation: Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Division of Intramural Population Health Research, Epidemiology Branch, Rockville, MD 20892, USA. Electronic address: pauline.mendola@mail.nih.gov.
authors.forename: Pauline
authors.initials: P
authors.lastname: Mendola
authors.affiliation: Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Division of Intramural Population Health Research, Epidemiology Branch, Rockville, MD 20892, USA.
authors.forename: Edwina
authors.initials: E
authors.lastname: Yeung
authors.affiliation: Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Division of Intramural Population Health Research, Epidemiology Branch, Rockville, MD 20892, USA.
authors.forename: Tuija
authors.initials: T
authors.lastname: Männistö
authors.affiliation: Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Division of Intramural Population Health Research, Biostatistics and Bioinformatics Branch, Rockville, MD 20892, USA.
authors.forename: Rajeshwari
authors.initials: R
authors.lastname: Sundaram
authors.affiliation: Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Division of Intramural Population Health Research, Biostatistics and Bioinformatics Branch, Rockville, MD 20892, USA.
authors.forename: Danping
authors.initials: D
authors.lastname: Liu
authors.affiliation: Texas A&M University, Zachary Department of Civil Engineering, College Station, TX 77845, USA.
authors.forename: Qi
authors.initials: Q
authors.lastname: Ying
authors.affiliation: The EMMES Corporation, Rockville, MD 20852, USA.
authors.forename: Seth
authors.initials: S
authors.lastname: Sherman
authors.affiliation: Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Division of Intramural Population Health Research, Epidemiology Branch, Rockville, MD 20892, USA.
authors.forename: Katherine L
authors.initials: KL
authors.lastname: Grantz
mesh_terms: D000328:Adult; D000393:Air Pollutants / Q000633:toxicity*; D016640:Diabetes, Gestational / Q000139:chemically induced / Q000453:epidemiology*; D005260:Female; D006801:Humans; D018811:Maternal Exposure; D008962:Models, Theoretical; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011262:Pregnancy Trimester, Second; D012189:Retrospective Studies; D018570:Risk Assessment; D012959:Socioeconomic Factors; D014481:United States / Q000453:epidemiology; D055815:Young Adult
chemical_list: D000393:Air Pollutants
keywords: Air pollution; Gestational diabetes; Preconception; Pregnancy