Traffic noise and risk of myocardial infarction.

Background: The biologic plausibility for noise stress-related cardiovascular responses is well established. Epidemiologic studies on the relationship between transportation noise and ischemic heart disease suggest a higher risk of myocardial infarction in subjects exposed to high levels of traffic noise.

Methods: To determine the risk of road traffic noise for the incidence of myocardial infarction (MI), we carried out a hospital-based case-control study in the city of Berlin. We enrolled consecutive patients (n=1881), age 20-69 years, with confirmed diagnosis of MI from 1998 through 2001. Controls (n=2234) were matched according to sex, age, and hospital. Outdoor traffic noise level was determined for each study subject based on noise maps of the city. Standardized interviews were conducted to assess possible confounding factors and the annoyance from various noise sources.

Results: The adjusted odds ratio for men exposed to sound levels of more than 70 dB(A) during the day was 1.3 (95% confidence interval=0.88-1.8) compared with those where the sound level did not exceed 60 dBA. In the subsample of men who lived for at least 10 years at their present address, the odds ratio was 1.8 (1.0-3.2). Noise-exposed women were not at higher risk.

Conclusions: The results support the hypothesis that chronic exposure to high levels of traffic noise increases the risk for cardiovascular diseases.