Air pollution has emerged as a major environmental risk factor for health. About 4.2 million deaths that occur every year have been attributed to ambient (outdoor) air pollution due to stroke, heart disease, lung cancer, acute and chronic respiratory diseases. Household pollution due to exposure to smoke from fuel also causes 3.8 million premature deaths annually. In 2016, ischemic heart disease and stroke caused around 58% of premature deaths due to outdoor pollution, while COPD and acute lower respiratory infections each caused 18% of deaths, as per WHO. Lung cancer accounted for 6% of deaths.¹ Pollutants with the strongest evidence for public health concern are particulate matter (PM), ozone (O3), nitrogen dioxide (NO2) and sulfur dioxide (SO2).

A new study reported in the Journal of the American Heart Association investigated the combined effects of exposure to air pollution and road traffic noise and showed an association of long-standing exposure to the air pollution and the noise pollution with an increased risk of developing heart failure. Former smokers or hypertensive patients were particularly at risk. ²

The prospective study investigated more than 22,000 members of the all-female Danish Nurse Cohort study. At the time of study entry, the participants were aged ≥44 years. They were asked to complete a comprehensive questionnaire on body mass index, lifestyle factors (smoking, alcohol consumption, physical activity and dietary habits), pre-existing health conditions, reproductive health and working conditions. Data was collected till December 2014.

Analysis of data revealed that exposure to air pollutants like particulate matter (PM2.5), nitrogen dioxide (NO2) and road traffic noise (within 3 km from the residence) increased the risk of heart failure. For every 5.1 µg/m3 increase in fine PM (<2.5 µm) exposure over 3 years, the risk of incident heart failure increased by 17% and for every 8.6 µg/m3 increase in NO2 exposure over three years, the risk of incident heart failure increased by 10%. Similarly, the risk of incident heart failure increased by 12% for every 9.3 dB increase in road traffic noise exposure over three years. The risk was 72% higher in former smokers.

This is the first study to examine the associations between PM2.5, NO2, and road traffic noise simultaneously with incident heart failure. While the association was stronger for air pollution as compared to road traffic noise, women who were exposed to both high levels of air pollution as well as road traffic noise were found to be at highest risk of developing heart failure. The study authors suggest that patients should be educated about the adverse effects of air pollution and road traffic noise on the heart.

Reference

1. WHO Fact Sheet. Ambient (outdoor) air pollution, 22 September 2021.
2. Lim YH, et al. Long-term exposure to air pollution, road traffic noise, and heart failure incidence: The Danish Nurse Cohort. J Am Heart Assoc. 2021 Oct 6;e021436. doi: 10.1161/JAHA.121.021436.