title: Exposure to traffic-related air pollution during pregnancy and term low birth weight: estimation of causal associations in a semiparametric model.
abstract: Traffic-related air pollution is recognized as an important contributor to health problems. Epidemiologic analyses suggest that prenatal exposure to traffic-related air pollutants may be associated with adverse birth outcomes; however, there is insufficient evidence to conclude that the relation is causal. The Study of Air Pollution, Genetics and Early Life Events comprises all births to women living in 4 counties in California's San Joaquin Valley during the years 2000-2006. The probability of low birth weight among full-term infants in the population was estimated using machine learning and targeted maximum likelihood estimation for each quartile of traffic exposure during pregnancy. If everyone lived near high-volume freeways (approximated as the fourth quartile of traffic density), the estimated probability of term low birth weight would be 2.27% (95% confidence interval: 2.16, 2.38) as compared with 2.02% (95% confidence interval: 1.90, 2.12) if everyone lived near smaller local roads (first quartile of traffic density). Assessment of potentially causal associations, in the absence of arbitrary model assumptions applied to the data, should result in relatively unbiased estimates. The current results support findings from previous studies that prenatal exposure to traffic-related air pollution may adversely affect birth weight among full-term infants.
authors.affiliation: Department of Epidemiology, School of Public Health, University of California, Berkeley, USA. padula@berkeley.edu
authors.forename: Amy M
authors.initials: AM
authors.lastname: Padula
authors.forename: Kathleen
authors.initials: K
authors.lastname: Mortimer
authors.forename: Alan
authors.initials: A
authors.lastname: Hubbard
authors.forename: Frederick
authors.initials: F
authors.lastname: Lurmann
authors.forename: Michael
authors.initials: M
authors.lastname: Jerrett
authors.forename: Ira B
authors.initials: IB
authors.lastname: Tager
mesh_terms: D000397:Air Pollution / Q000009:adverse effects* / Q000706:statistics & numerical data; D002140:California / Q000453:epidemiology; D004781:Environmental Exposure / Q000009:adverse effects* / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D008297:Male; D008423:Maternal Age; D011247:Pregnancy; D011248:Pregnancy Complications / Q000139:chemically induced* / Q000453:epidemiology; D011297:Prenatal Exposure Delayed Effects / Q000139:chemically induced / Q000453:epidemiology; D012111:Residence Characteristics / Q000706:statistics & numerical data; D012737:Sex Factors; D012959:Socioeconomic Factors; D001335:Vehicle Emissions / Q000633:toxicity*
chemical_list: D001335:Vehicle Emissions