Author(s): Röösli Martin, Héritier Harris, Foraster Maria, Eze Ikenna, De Hoogh Kees, Brink Mark, Cajochen Christian, Wunderli Jean-Marc, Probst-Hensch Nicole, Vienneau Danielle
Transportation noise and air pollutants were found to be associated with myocardial infarction (MI) risk. The present study aimed to disentangle the risk of the three major transportation noise sources – road, railway and aircraft traffic– and the air pollutants NO2 and PM2.5 on MI mortality in Switzerland using the nationwide Swiss National Cohort. We modeled outdoor road traffic, railway and aircraft noise levels (Lden, dB) at the most exposed residential façade for 2001, and average residential NO2 and PM2.5 concentration during follow-up. We investigated the impact of adjusting the noise estimates for NO2 and/or PM2.5 and vice versa by multipollutant Cox regression models adjusted for potential sociodemographic confounders. A total of 19,313 MI deaths occurred in the cohort of 4.41 million adults older than 30 years between 2000 and 2008. Among the exposure estimates, the highest Spearman rank correlation coefficients were observed between NO2 and PM2.5 (0.62) and between NO2 and Lden,road (0.44). Adjusting noise risk estimates of IHD and MI for NO2 and/or PM2.5 virtually did not change the hazard ratios in linear exposure-response models. For instance the hazard ratio of MI per 10 dB Lden,road: 1.036 (95% CI 1.017-1.054) changed to 1.038 (1.018-1.059) after adjusting for NO2 and PM2.5. Conversely risk estimates for air pollution exposure tended to decrease upon adjustment for all noise sources. For instance the hazard ratio for MI per 10 dB PM2.5: 1.048 (1.008-1.089) decreased to 1.009 (0.968-1.052) after adjusting for road, railway and aircraft noise. In conclusion, this study suggests that transportation noise is independently associated with IHD and MI mortality. However, air pollution studies not adequately adjusting for transportation noise exposure may overestimate the cardiovascular disease risk.
Name: Prof Martin Röösli