title: Proximity to traffic, ambient air pollution, and community noise in relation to incident rheumatoid arthritis.
abstract: BACKGROUND
  The risk of rheumatoid arthritis (RA) has been associated with living near traffic; however, there is evidence suggesting that air pollution may not be responsible for this association. Noise, another traffic-generated exposure, has not been studied as a risk factor for RA.
  
  
  OBJECTIVE
  We investigated proximity to traffic, ambient air pollution, and community noise in relation to RA in the Vancouver and Victoria regions of British Columbia, Canada.
  
  
  METHODS
  Cases and controls were identified in a cohort of adults that was assembled using health insurance registration records. Incident RA cases from 1999 through 2002 were identified by diagnostic codes in combination with prescriptions and type of physician (e.g., rheumatologist). Controls were matched to RA cases by age and sex. Environmental exposures were assigned to each member of the study population by their residential postal code(s). We estimated relative risks using conditional logistic regression, with additional adjustment for median income at the postal code.
  
  
  RESULTS
  RA incidence was increased with proximity to traffic, with an odds ratio (OR) of 1.37 (95% CI: 1.11, 1.68) for residence ≤ 50 m from a highway compared with residence > 150 m away. We found no association with traffic-related exposures such as PM2.5, nitrogen oxides, or noise. Ground-level ozone, which was highest in suburban areas, was associated with an increased risk of RA (OR = 1.26; 95% CI: 1.18, 1.36 per interquartile range increase).
  
  
  CONCLUSIONS
  Our study confirms a previously observed association of RA risk with proximity to traffic and suggests that neither noise levels nor traffic-related air pollutants are responsible for this relationship. Additional investigation of neighborhood and individual correlates of residence near roadways may provide new insight into risk factors for RA.
authors.affiliation: Department of Environmental and Occupational Health, School of Public Health, Drexel University, Philadelphia, Pennsylvania, USA.
authors.forename: Anneclaire J
authors.initials: AJ
authors.lastname: De Roos
authors.forename: Mieke
authors.initials: M
authors.lastname: Koehoorn
authors.forename: Lillian
authors.initials: L
authors.lastname: Tamburic
authors.forename: Hugh W
authors.initials: HW
authors.lastname: Davies
authors.forename: Michael
authors.initials: M
authors.lastname: Brauer
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000393:Air Pollutants / Q000032:analysis*; D000397:Air Pollution / Q000009:adverse effects / Q000706:statistics & numerical data*; D001172:Arthritis, Rheumatoid / Q000139:chemically induced / Q000453:epidemiology*; D001955:British Columbia / Q000453:epidemiology; D004781:Environmental Exposure / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009589:Nitrogen Oxides / Q000032:analysis; D009622:Noise; D010126:Ozone / Q000032:analysis; D052638:Particulate Matter / Q000032:analysis; D014186:Transportation; D001335:Vehicle Emissions / Q000032:analysis
chemical_list: D000393:Air Pollutants; D009589:Nitrogen Oxides; D052638:Particulate Matter; D001335:Vehicle Emissions; D010126:Ozone