Air pollution and traffic noise: do they cause atherosclerosis?

Abstract

This editorial refers to ‘Are air pollution and traffic noise independently associated with atherosclerosis: the Heinz Nixdorf Recall Study’[†][1], by H. Kalsch et al. , on page 853 The great majority of the world's population is continuously exposed to some level of air pollution from transportation, household sources, agriculture, and industry, and many are also exposed to ambient noise from the same sources. It has been estimated that globally ∼3 million premature deaths are attributable to outdoor air pollution each year,1 but it is the ubiquity of air pollution and ambient noise, as much as the likely magnitudes of associated risks, which makes them important as potential causes of cardiovascular diseases. Because they share common sources, air pollution and ambient noise are correlated, and this means that any association of cardiovascular disease with either exposure may be masked or confounded by the other. Despite this, most studies have considered traffic noise or air pollution separately, and the study by Kalsch and colleagues2 is one of a limited number that have attempted to disentangle their effects on cardiovascular outcomes.3 Although their results are suggestive of independent effects of long-term particulate air pollution and night-time traffic noise on thoracic aortic calcification (TAC), they should be interpreted cautiously. Air pollution includes a variety of gaseous species, such as carbon monoxide and nitrogen oxides, as well as suspended particulate matter of various sizes. Many of these have been shown in isolation to have adverse effects on cardiovascular health at higher doses, such as those experienced by active smokers of tobacco.4 Observational studies also provide substantial evidence of effects on cardiovascular health at lower levels of exposure due to ambient air pollution, particularly for the risk of acute events such as myocardial infarction5 or heart failure6 in response to short-term … [1]: #fn-2