title: Residential proximity to major roads and placenta/birth weight ratio.
abstract: Exposure to air pollution has been demonstrated to increase the risk of preterm birth and low birth weight. We examined whether proximity to major roads (as a marker of exposure to air pollution) is associated with increased placenta/birth weight ratio (as a biomarker of the placental transport function). Data on parental characteristics and birth outcomes were extracted from the database maintained by a major hospital in Shizuoka Prefecture, Japan. We restricted the analysis to mothers who delivered liveborn single births from 1997 to 2008 (n = 14,189). Using geocoded residential information, each birth was classified according to proximity to major roads. We examined the association between proximity to major roads and the placenta/birth weight ratio, using multiple linear regression. Proximity to major roads was associated with higher placenta/birth weight ratio. After adjusting for potential confounders, living within 200 m of a major road increased the ratio by 0.48% (95% CI = 0.15 to 0. 80). In addition, proximity to major roads was associated with lower placenta weight and birth weight. These observed associations were stronger among participants living closer to major roads. Exposure to traffic-related air pollution is associated with higher placenta/birth weight ratio. Impaired placental oxygen and nutrient transport function might be a mechanism for explaining the observed association between air pollution and low birth weight as well as preterm birth.
authors.affiliation: Department of Epidemiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama 700-8558, Japan. yorichan@md.okayama-u.ac.jp
authors.forename: Takashi
authors.initials: T
authors.lastname: Yorifuji
authors.forename: Hiroo
authors.initials: H
authors.lastname: Naruse
authors.forename: Saori
authors.initials: S
authors.lastname: Kashima
authors.forename: Takeshi
authors.initials: T
authors.lastname: Murakoshi
authors.forename: Toshihide
authors.initials: T
authors.lastname: Tsuda
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Doi
authors.forename: Ichiro
authors.initials: I
authors.lastname: Kawachi
mesh_terms: D001724:Birth Weight / Q000187:drug effects / Q000502:physiology*; D005260:Female; D006798:Housing; D006801:Humans; D007564:Japan; D016014:Linear Models; D010920:Placenta / Q000187:drug effects / Q000502:physiology*; D011247:Pregnancy; D014186:Transportation; D001335:Vehicle Emissions / Q000633:toxicity*
chemical_list: D001335:Vehicle Emissions