Residential proximity to major roads and preterm births.
BACKGROUND
Preterm births cause a large public-health burden, and air pollution is considered to be a potential risk factor. We evaluated the association between proximity to major roads (as an index for air pollution) and preterm births, classified by gestational age and specific clinical manifestations.


METHODS
Data on parental information and birth outcomes were extracted from the database maintained by the perinatal hospital in Shizuoka, Japan. We restricted the analysis to mothers who delivered liveborn single births from 1997 to 2008 (n = 14,226). Using the geocoded residential information, each birth was classified on its proximity to major roads. We estimated the multivariate-adjusted odds ratios and their 95% confidence intervals (CIs) for the association of proximity to major roads with preterm births, using logistic regression.


RESULTS
We found positive associations between proximity to major roads and preterm births at all gestational ages. Living within 200 m increased the risk of births before 37 weeks by 1.5 times (95% CI = 1.2-1.8), birth before 32 weeks by 1.6 times (1.1-2.4), and births before 28 weeks by 1.8 times (1.0-3.2). Proximity specifically increased the risk of preterm births with preterm premature rupture of the membranes and with pregnancy hypertension.


CONCLUSIONS
This study demonstrates that exposure to traffic-related air pollution increases even the risk of preterm births of less than 30 weeks' gestational age and proposes a possible mechanism.
Department of Epidemiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan. yorichan@md.okayama-u.ac.jp
Takashi
T
Yorifuji
Hiroo
H
Naruse
Saori
S
Kashima
Shigeru
S
Ohki
Takeshi
T
Murakoshi
Soshi
S
Takao
Toshihide
T
Tsuda
Hiroyuki
H
Doi
D000328:Adult; D000393:Air Pollutants / Q000009:adverse effects*; D016001:Confidence Intervals; D016208:Databases, Factual; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007564:Japan; D016017:Odds Ratio; D011247:Pregnancy; D047928:Premature Birth / Q000453:epidemiology*; D012111:Residence Characteristics; D001335:Vehicle Emissions; D055815:Young Adult
D000393:Air Pollutants; D001335:Vehicle Emissions