title: Cardiovascular health, traffic-related air pollution and noise: are associations mutually confounded? A systematic review.
abstract: OBJECTIVE
  This review assessed the confounding effect of one traffic-related exposure (noise or air pollutants) on the association between the other exposure and cardiovascular outcomes.
  
  
  METHODS
  A systematic review was conducted with the databases Medline and Embase. The confounding effects in studies were assessed by using change in the estimate with a 10 % cutoff point. The influence on the change in the estimate of the quality of the studies, the exposure assessment methods and the correlation between road noise and air pollutions were also assessed.
  
  
  RESULTS
  Nine publications were identified. For most studies, the specified confounders produced changes in estimates <10 %. The correlation between noise and pollutants, the quality of the study and of the exposure assessment do not seem to influence the confounding effects.
  
  
  CONCLUSIONS
  Results from this review suggest that confounding of cardiovascular effects by noise or air pollutants is low, though with further improvements in exposure assessment, the situation may change. More studies using pollution indicators specific to road traffic are needed to properly assess if noise and air pollution are subjected to confounding.
authors.affiliation: Département de santé environnementale et santé au travaill, University of Montreal, 2375 Chemin de la Côte-Sainte-Catherine, Montréal, QC, H3T 1A8, Canada, ltetreau@santepub-mtl.qc.ca.
authors.forename: Louis-François
authors.initials: LF
authors.lastname: Tétreault
authors.forename: Stéphane
authors.initials: S
authors.lastname: Perron
authors.forename: Audrey
authors.initials: A
authors.lastname: Smargiassi
mesh_terms: D000393:Air Pollutants / Q000009:adverse effects; D000397:Air Pollution / Q000009:adverse effects*; D002318:Cardiovascular Diseases / Q000453:epidemiology* / Q000209:etiology*; D015986:Confounding Factors, Epidemiologic; D006801:Humans; D018986:Motor Vehicles; D009622:Noise / Q000009:adverse effects*; D052638:Particulate Matter / Q000009:adverse effects
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter