A study published in Circulation journal in Aug 2018 showed individuals exposed to traffic-related air pollution had enlarged heart chambers, a clear sign of heart failure development pattern.
Summary Points and Comments
- The study tracked heart MRIs of 3920 adults, who did not have heart disease, over a median of 5.2 years.
- The average annual air pollution levels at participants’ home addresses at the start of the study were recorded. Half the participants had annual average PM2.5 levels of less than 9.9 µg/m3. PM2.5 means fine particulate matter of 2.5 micrometer or smaller. These polluting particles are dangerous because they go into the lungs, and are often absorbed into the blood.
- World Health Organisation (WHO) says there is no absolute safe limit for PM2.5 exposure. However, it guides annual PM2.5 average exposure less than 10 µg/m3 to be generally safe. Thus, half the patients in the study had PM2.5 exposure less than the ‘safe’ limits.
- Enlargement of heart muscles make them too weak to pump blood into the body. This can lead to tiredness, fluid retention and resultant weight gain, coughing, wheezing and shortness of breath. Eventually, such a weak heart fails leading to death.
- For every 1 µg/m3 increase in PM2.5 exposure, the heart enlargement was about 1%.
One possible theory is when polluted air is inhaled, it can cause swelling in lungs and blood vessels. Over a period of time, this can lead to heart failure even in people not having any prior heart disease.
Read about the research here – https://www.ahajournals.org/doi/abs/10.1161/CIRCULATIONAHA.118.034856