title: Joint effects of job strain and road-traffic and occupational noise on myocardial infarction.
abstract: OBJECTIVE
  The aim of this study was to assess the joint effect of job strain and both road-traffic and occupational noise on myocardial infarction (MI).
  
  
  METHODS
  We conducted a population based case-control study on first time MI in Stockholm County during 1992-1994. Participants answered a questionnaire and underwent a physical examination. Residential road-traffic noise exposure was based on residential history combined with information on traffic intensity and distance to nearby roads. Occupational noise exposure was assessed by occupational history combined with a job-exposure matrix derived from measurements. Job strain was based on questions regarding psychological demands and decision latitude. A total of 3050 study participants (1252 cases and 1798 controls) were included in the study.
  
  
  RESULTS
  An increased risk of MI was indicated among participants exposed to road-traffic noise [odds ratio (OR) 1.23, 95% confidence interval (95% CI) 1.01-1.51], occupational noise (OR 1.17, 95% CI 0.98-1.41) and job strain (OR 1.39, 95% CI 1.17-1.65). Participants exposed to one, two, or three of these factors showed an increased risk (OR 1.16, 95% CI 0.97-1.40, OR 1.57, 95% CI 1.24-1.98, and OR 2.27, 95% CI 1.41-3.64, respectively). Exposure to two or three of these factors occurred among about 20% of the controls.
  
  
  CONCLUSIONS
  Our results indicate that exposure to a combination of noise exposure and job strain increases the risk of MI substantially. Such exposures affect a considerable part of the population, which has relevance for prioritization of preventative measures.
authors.affiliation: Institute of Environmental Medicine, Unit of Occupational Medicine, Karolinska Institutet, Stockholm, Sweden. jenny.selander@ki.se
authors.forename: Jenny
authors.initials: J
authors.lastname: Selander
authors.forename: Gösta
authors.initials: G
authors.lastname: Bluhm
authors.forename: Mats
authors.initials: M
authors.lastname: Nilsson
authors.forename: Johan
authors.initials: J
authors.lastname: Hallqvist
authors.forename: Töres
authors.initials: T
authors.lastname: Theorell
authors.forename: Pernilla
authors.initials: P
authors.lastname: Willix
authors.forename: Göran
authors.initials: G
authors.lastname: Pershagen
mesh_terms: D000368:Aged; D000397:Air Pollution / Q000009:adverse effects / Q000706:statistics & numerical data; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000453:epidemiology* / Q000209:etiology; D009623:Noise, Occupational / Q000009:adverse effects / Q000706:statistics & numerical data*; D009624:Noise, Transportation / Q000009:adverse effects / Q000706:statistics & numerical data*; D016273:Occupational Exposure / Q000009:adverse effects / Q000706:statistics & numerical data*; D013315:Stress, Psychological / Q000453:epidemiology*; D013548:Sweden / Q000453:epidemiology