title: Prenatal exposure to traffic pollution: associations with reduced fetal growth and rapid infant weight gain.
abstract: BACKGROUND
  Prenatal air pollution exposure inhibits fetal growth, but implications for postnatal growth are unknown.
  
  
  METHODS
  We assessed weights and lengths of US infants in the Project Viva cohort at birth and 6 months. We estimated 3rd-trimester residential air pollution exposures using spatiotemporal models. We estimated neighborhood traffic density and roadway proximity at birth address using geographic information systems. We performed linear and logistic regression adjusted for sociodemographic variables, fetal growth, and gestational age at birth.
  
  
  RESULTS
  Mean birth weight-for-gestational age z-score (fetal growth) was 0.17 (standard deviation [SD] = 0.97; n = 2,114), 0- to 6-month weight-for-length gain was 0.23 z-units (SD = 1.11; n = 689), and 17% had weight-for-length ≥95th percentile at 6 months of age. Infants exposed to the highest (vs. lowest) quartile of neighborhood traffic density had lower fetal growth (-0.13 units [95% confidence interval (CI) = -0.25 to -0.01]), more rapid 0- to 6-month weight-for-length gain (0.25 units [95% CI = 0.01 to 0.49]), and higher odds of weight-for-length ≥95th percentile at 6 months (1.84 [95% CI = 1.11 to 3.05]). Neighborhood traffic density was additionally associated with an infant being in both the lowest quartile of fetal growth and the highest quartile of 0- to 6-month weight-for-length gain (Q4 vs. Q1, odds ratio = 3.01 [95% CI = 1.08 to 8.44]). Roadway proximity and 3rd-trimester black carbon exposure were similarly associated with growth outcomes. For 3rd-trimester particulate matter (PM2.5), effect estimates were in the same direction, but smaller and imprecise.
  
  
  CONCLUSIONS
  Infants exposed to higher traffic-related pollution in early life may exhibit more rapid postnatal weight gain in addition to reduced fetal growth.
authors.affiliation: From the aDivision of Endocrinology, Boston Children's Hospital, Boston, MA; bObesity Prevention Program, Department of Population Medicine, Harvard Medical School and Harvard Pilgrim Health Care Institute, Boston, MA; cDepartment of Environmental Health, Harvard School of Public Health, Boston, MA; dDepartment of Geography and Environmental Development, Ben-Gurion University of the Negev, Beer Sheva, Israel; eDepartments of Biostatistics and fNutrition, Harvard School of Public Health, Boston, MA; gChanning Laboratory, Brigham and Women's Hospital, Boston, MA.
authors.forename: Abby F
authors.initials: AF
authors.lastname: Fleisch
authors.forename: Sheryl L
authors.initials: SL
authors.lastname: Rifas-Shiman
authors.forename: Petros
authors.initials: P
authors.lastname: Koutrakis
authors.forename: Joel D
authors.initials: JD
authors.lastname: Schwartz
authors.forename: Itai
authors.initials: I
authors.lastname: Kloog
authors.forename: Steven
authors.initials: S
authors.lastname: Melly
authors.forename: Brent A
authors.initials: BA
authors.lastname: Coull
authors.forename: Antonella
authors.initials: A
authors.lastname: Zanobetti
authors.forename: Matthew W
authors.initials: MW
authors.lastname: Gillman
authors.forename: Diane R
authors.initials: DR
authors.lastname: Gold
authors.forename: Emily
authors.initials: E
authors.lastname: Oken
mesh_terms: D000397:Air Pollution / Q000706:statistics & numerical data*; D001724:Birth Weight; D015331:Cohort Studies; D005260:Female; D005317:Fetal Growth Retardation / Q000453:epidemiology*; D005865:Gestational Age; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D018811:Maternal Exposure / Q000706:statistics & numerical data*; D052638:Particulate Matter; D063766:Pediatric Obesity / Q000453:epidemiology; D011247:Pregnancy; D011263:Pregnancy Trimester, Third; D011297:Prenatal Exposure Delayed Effects / Q000453:epidemiology*; D062211:Spatio-Temporal Analysis; D014481:United States / Q000453:epidemiology; D001335:Vehicle Emissions; D015430:Weight Gain
chemical_list: D052638:Particulate Matter; D001335:Vehicle Emissions