Long-Term Exposure to Road Traffic Noise and Nitrogen Dioxide and Risk of Heart Failure: A Cohort Study

BACKGROUND: Although air pollution and road traffic noise have been associated with higher risk of cardiovascular diseases, associations with heart failure have received only little attention. OBJECTIVES: We aimed to investigate whether long-term exposure to road traffic noise and nitrogen dioxide (NO2) were associated with incident heart failure. METHODS: In a cohort of 57,053 people 50-64 y of age at enrollment in the period 1993-1997, we identified 2,550 cases of first-ever hospital admission for heart failure during a mean follow-up time of 13.4 y. Present and historical residential addresses from 1987 to 2011 were found in national registers, and road traffic noise (L-den) and NO2 were modeled for all addresses. Analyses were done using Cox proportional hazard model. RESULTS: An interquartile range higher 10-y time-weighted mean exposure for L-den and NO2 was associated with incidence rate ratios (IRR) for heart failure of 1.14 (1.08-1.21) and 1.11 (1.07-1.16), respectively, in models adjusted for gender, lifestyle, and socioeconomic status. In models with mutual exposure adjustment, IRRs were 1.08 (1.00-1.16) for L-den and 1.07 (1.01-1.14) for NO2. We found statistically significant modification of the NO2 heart failure association by gender (strongest association among men), baseline hypertension (strongest association among hypertensive), and diabetes (strongest association among diabetics). The same tendencies were seen for noise, but interactions were not statistically significant. CONCLUSIONS: Long-term exposure to NO2 and road traffic noise was associated with higher risk of heart failure, mainly among men, in both single and two-pollutant models. High exposure to both pollutants was associated with highest risk.