title: Impact of Road Traffic Pollution on Pre-eclampsia and Pregnancy-induced Hypertensive Disorders.
abstract: Road traffic is a major source of air pollution and noise. Both exposures have been associated with hypertension in adults, but pregnant women have been less studied.
  
  
  
  We examined single and joint effects of ambient air pollution and road traffic noise on pre-eclampsia and pregnancy-induced hypertensive disorders among 72,745 singleton pregnancies (1997-2002) from the Danish National Birth Cohort with complete covariate data and residential address history from conception until live born birth. Nitrogen dioxide (NO2) and noise from road traffic (Lden) were modeled at all addresses. Outcome and covariate data were derived from registries, hospital records, and questionnaires.
  
  
  
  A 10-µg/m increase in NO2 exposure during first trimester was associated with increased risk of pre-eclampsia (n = 1,880, adjusted odds ratio = 1.07 [95% confidence interval = 1.01, 1.14]) and pregnancy-induced hypertensive disorders (n = 2,430, adjusted odds ratio = 1.07 [1.01, 1.13]). A 10 dB higher road traffic noise was also associated with increased risk of pre-eclampsia (1.10 [1.02, 1.18]) and pregnancy-induced hypertensive disorders (1.08 [1.02, 1.15]). For both exposures, the associations were strongest for mild pre-eclampsia (n = 1,393) and early-onset pre-eclampsia (n = 671), whereas higher risk for severe pre-eclampsia (n = 487) was not evident. In mutually adjusted models, estimates for both exposures decreased and only the association between NO2 and mild pre-eclampsia remained.
  
  
  
  Road traffic may increase the risk of pre-eclampsia and hypertensive disorders in pregnancy through exposure to both ambient air pollution and noise, although associations with the two exposures were generally not found to be independent of one another. See video abstract, http://links.lww.com/EDE/B112.
authors.affiliation: From the aCentre for Epidemiology and Screening, Department of Public Health, University of Copenhagen, Copenhagen, Denmark; bDanish Cancer Society Research Center, Copenhagen, Denmark; cCentre for Fetal Programming, Department of Epidemiology Research, Statens Serum Institute, Copenhagen, Denmark; dFaculty of Food Science and Nutrition, University of Iceland, Reykjavik, Iceland; eDepartment of Nutrition, Harvard School of Public Health, Boston, MA; and fDepartment of Environmental Science, Aarhus University, Roskilde, Denmark.
authors.forename: Marie
authors.initials: M
authors.lastname: Pedersen
authors.forename: Thorhallur I
authors.initials: TI
authors.lastname: Halldorsson
authors.forename: Sjurdur F
authors.initials: SF
authors.lastname: Olsen
authors.forename: Dorrit
authors.initials: D
authors.lastname: Hjortebjerg
authors.forename: Matthias
authors.initials: M
authors.lastname: Ketzel
authors.forename: Charlotta
authors.initials: C
authors.lastname: Grandström
authors.forename: Ole
authors.initials: O
authors.lastname: Raaschou-Nielsen
authors.forename: Mette
authors.initials: M
authors.lastname: Sørensen
mesh_terms: D000328:Adult; D000397:Air Pollution; D003718:Denmark / Q000453:epidemiology; D005260:Female; D006801:Humans; D046110:Hypertension, Pregnancy-Induced / Q000453:epidemiology; D009585:Nitrogen Dioxide; D009624:Noise, Transportation; D016017:Odds Ratio; D011225:Pre-Eclampsia / Q000453:epidemiology*; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D012720:Severity of Illness Index; D001335:Vehicle Emissions
chemical_list: D001335:Vehicle Emissions; D009585:Nitrogen Dioxide