title: Maternal exposure to moderate ambient carbon monoxide is associated with decreased risk of preeclampsia.
abstract: OBJECTIVE
  Carbon monoxide (CO) in cigarette smoke may be the mechanism by which tobacco use during pregnancy decreases the risk of the development of preeclampsia. We attempted to test this hypothesis by examining the effect of maternal exposure to ambient CO on preeclampsia.
  
  
  METHODS
  Births that occurred between 2004 and 2009 in the Canadian province of Ontario were extracted from the data. Study subjects were divided into 4 groups according to quartiles of CO concentration that were based on maternal residence. Adjusted odds ratio and 95% confidence interval were used to estimate the independent effect of CO on preeclampsia.
  
  
  RESULTS
  Rates of preeclampsia were 2.32%, 1.97%, 1.59%, and 1.26%, respectively, in the first, second, third, and fourth quartile of CO concentration. The inverse association between CO concentration and preeclampsia risk remained the same after adjustment for several important confounding factors.
  
  
  CONCLUSIONS
  Maternal exposure to moderate ambient CO is associated independently with a decreased risk of preeclampsia.
authors.affiliation: School of Public Health, Central South University, Changsha, Hunan, People's Republic of China.
authors.forename: Desheng
authors.initials: D
authors.lastname: Zhai
authors.forename: Yanfang
authors.initials: Y
authors.lastname: Guo
authors.forename: Graeme
authors.initials: G
authors.lastname: Smith
authors.forename: Daniel
authors.initials: D
authors.lastname: Krewski
authors.forename: Mark
authors.initials: M
authors.lastname: Walker
authors.forename: Shi Wu
authors.initials: SW
authors.lastname: Wen
mesh_terms: D000328:Adult; D000393:Air Pollutants / Q000032:analysis; D000397:Air Pollution / Q000032:analysis / Q000706:statistics & numerical data*; D001724:Birth Weight; D002248:Carbon Monoxide / Q000032:analysis; D015331:Cohort Studies; D005260:Female; D005317:Fetal Growth Retardation / Q000209:etiology / Q000517:prevention & control; D006801:Humans; D007231:Infant, Newborn; D016014:Linear Models; D016015:Logistic Models; D018811:Maternal Exposure / Q000706:statistics & numerical data*; D009864:Ontario; D011225:Pre-Eclampsia / Q000209:etiology* / Q000517:prevention & control; D011247:Pregnancy; D012042:Registries; D012306:Risk
chemical_list: D000393:Air Pollutants; D002248:Carbon Monoxide