title: Association between local traffic-generated air pollution and preeclampsia and preterm delivery in the south coast air basin of California.
abstract: BACKGROUND
  Preeclampsia is a major complication of pregnancy that can lead to substantial maternal and perinatal morbidity, mortality, and preterm birth. Increasing evidence suggests that air pollution adversely affects pregnancy outcomes. Yet few studies have examined how local traffic-generated emissions affect preeclampsia in addition to preterm birth.
  
  
  OBJECTIVE
  We examined effects of residential exposure to local traffic-generated air pollution on preeclampsia and preterm delivery (PTD).
  
  
  METHODS
  We identified 81,186 singleton birth records from four hospitals (1997-2006) in Los Angeles and Orange Counties, California (USA). We used a line-source dispersion model (CALINE4) to estimate individual exposure to local traffic-generated nitrogen oxides (NO(x)) and particulate matter < 2.5 mum in aerodynamic diameter (PM(2.5)) across the entire pregnancy. We used logistic regression to estimate effects of air pollution exposures on preeclampsia, PTD (gestational age < 37 weeks), moderate PTD (MPTD; gestational age < 35 weeks), and very PTD (VPTD; gestational age < 30 weeks).
  
  
  RESULTS
  We observed elevated risks for preeclampsia and preterm birth from maternal exposure to local traffic-generated NO(x) and PM(2.5). The risk of preeclampsia increased 33% [odds ratio (OR) = 1.33; 95% confidence interval (CI), 1.18-1.49] and 42% (OR = 1.42; 95% CI, 1.26-1.59) for the highest NO(x) and PM(2.5) exposure quartiles, respectively. The risk of VPTD increased 128% (OR = 2.28; 95% CI, 2.15-2.42) and 81% (OR = 1.81; 95% CI, 1.71-1.92) for women in the highest NO(x) and PM(2.5) exposure quartiles, respectively.
  
  
  CONCLUSIONS
  Exposure to local traffic-generated air pollution during pregnancy increases the risk of preeclampsia and preterm birth in Southern California women. These results provide further evidence that air pollution is associated with adverse reproductive outcomes.
authors.affiliation: Program in Public Health, College of Health Sciences, University of California, Irvine, California 92697-7555, USA. junwu@uci.edu
authors.forename: Jun
authors.initials: J
authors.lastname: Wu
authors.forename: Cizao
authors.initials: C
authors.lastname: Ren
authors.forename: Ralph J
authors.initials: RJ
authors.lastname: Delfino
authors.forename: Judith
authors.initials: J
authors.lastname: Chung
authors.forename: Michelle
authors.initials: M
authors.lastname: Wilhelm
authors.forename: Beate
authors.initials: B
authors.lastname: Ritz
mesh_terms: D000393:Air Pollutants / Q000633:toxicity*; D000397:Air Pollution / Q000009:adverse effects; D002140:California / Q000453:epidemiology; D004781:Environmental Exposure / Q000009:adverse effects; D005260:Female; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D018811:Maternal Exposure / Q000009:adverse effects; D009569:Nitric Oxide / Q000032:analysis; D016017:Odds Ratio; D052638:Particulate Matter / Q000009:adverse effects; D011225:Pre-Eclampsia / Q000453:epidemiology / Q000209:etiology*; D011247:Pregnancy; D011256:Pregnancy Outcome; D047928:Premature Birth / Q000453:epidemiology / Q000209:etiology*; D012307:Risk Factors; D001335:Vehicle Emissions / Q000633:toxicity*; D055815:Young Adult
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter; D001335:Vehicle Emissions; D009569:Nitric Oxide