title: Birth outcomes and prenatal exposure to ozone, carbon monoxide, and particulate matter: results from the Children's Health Study.
abstract: Exposures to ambient air pollutants have been associated with adverse birth outcomes. We investigated the effects of air pollutants on birth weight mediated by reduced fetal growth among term infants who were born in California during 1975-1987 and who participated in the Children's Health Study. Birth certificates provided maternal reproductive history and residence location at birth. Sociodemographic factors and maternal smoking during pregnancy were collected by questionnaire. Monthly average air pollutant levels were interpolated from monitors to the ZIP code of maternal residence at childbirth. Results from linear mixed-effects regression models showed that a 12-ppb increase in 24-hr ozone averaged over the entire pregnancy was associated with 47.2 g lower birth weight [95% confidence interval (CI), 27.4-67.0 g], and this association was most robust for exposures during the second and third trimesters. A 1.4-ppm difference in first-trimester carbon monoxide exposure was associated with 21.7 g lower birth weight (95% CI, 1.1-42.3 g) and 20% increased risk of intrauterine growth retardation (95% CI, 1.0-1.4). First-trimester CO and third-trimester O3 exposures were associated with 20% increased risk of intrauterine growth retardation. A 20-microg/m3 difference in levels of particulate matter < or = 10 microm in aerodynamic diameter (PM10) during the third trimester was associated with a 21.7-g lower birth weight (95% CI, 1.1-42.2 g), but this association was reduced and not significant after adjusting for O3. In summary, O3 exposure during the second and third trimesters and CO exposure during the first trimester were associated with reduced birth weight.
authors.affiliation: Department of Preventive Medicine, University of Southern California, Keck School of Medicine, Los Angeles, California 90033, USA.
authors.forename: Muhammad T
authors.initials: MT
authors.lastname: Salam
authors.forename: Joshua
authors.initials: J
authors.lastname: Millstein
authors.forename: Yu-Fen
authors.initials: YF
authors.lastname: Li
authors.forename: Frederick W
authors.initials: FW
authors.lastname: Lurmann
authors.forename: Helene G
authors.initials: HG
authors.lastname: Margolis
authors.forename: Frank D
authors.initials: FD
authors.lastname: Gilliland
mesh_terms: D000328:Adult; D000393:Air Pollutants / Q000633:toxicity*; D001724:Birth Weight; D002140:California; D002248:Carbon Monoxide / Q000633:toxicity*; D004391:Dust; D005260:Female; D005317:Fetal Growth Retardation / Q000139:chemically induced*; D006801:Humans; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D008297:Male; D018811:Maternal Exposure; D009585:Nitrogen Dioxide / Q000633:toxicity; D010126:Ozone / Q000633:toxicity*; D010316:Particle Size; D011247:Pregnancy
chemical_list: D000393:Air Pollutants; D004391:Dust; D010126:Ozone; D002248:Carbon Monoxide; D009585:Nitrogen Dioxide