Regular exposure to even low levels of air pollution bad for Heart

A new study sponsored by British Heart Foundation has revealed that Regular exposure to even low levels of air pollution bad for Heart.

According to the researchers, people exposed to air pollution levels well within UK guidelines have changes in the structure of the heart, similar to those seen in the early stages of heart failure. The research has been published in the journal Circulation.

Air pollution is one of the largest environmental risk factor linked to deaths globally. According to an estimate, coronary heart disease and stroke account for approximately six in ten (58%) deaths related to outdoor air pollution. The present research may help explain exactly how and why air pollution affects the heart.

Professor Steffen Petersen at Queen Mary University of London and colleagues screened data from around 4,000 participants in the UK Biobank study. The personal information of subjects, including their lifestyles, health record and details on where they have lived was obtained, so that the research team could remove patients with underlying heart problems, or those who had moved house during the study. All the participants were subjected to blood tests and health scans. Heart MRI was used to measure the size, weight and function of the participants' hearts at allocated times.

The researchers found that there was a clear association between those who lived near loud, busy roads, and were exposed to nitrogen dioxide (NO2) or PM2.5 - small particles of air pollution - and the development of larger right and left ventricles in the heart.

Higher exposures to the pollutants were linked to more significant changes in the structure of the heart and for every 1 extra μg per cubic metre of PM2.5 and for every 10 extra μg per cubic metre of NO2, the heart enlarges by approximately 1% .

Dr Nay Aung who led the data analysis from Queen Mary University of London said:

"Although our study was observational and hasn't yet shown a causal link, we saw significant changes in the heart, even at relatively low levels of air pollution exposure. Our future studies will include data from those living in inner cities like Central Manchester and London, using more in-depth measurements of heart function, and we would expect the findings to be even more pronounced and clinically important.

"Air pollution should be seen as a modifiable risk factor. Doctors and the general public all need to be aware of the their exposure when they think about their heart health, just like they think about their blood pressure, their cholesterol and their weight."

According to the WHO, there are no safe limits of PM2.5. In the study, average annual exposures to PM2.5 (8-12μg per cubic metre) were well within UK guidelines (25μg per cubic metre), but were equal to or more than World Health Organisation (WHO) guidelines (10μg per cubic metre). The participants' average exposure to NO2 (10-50μg per cubic metre) was approaching and above the equal WHO and UK annual average guidelines (40μg per cubic metre).

Professor Jeremy Pearson, Associate Medical Director at the British Heart Foundation, which part-funded the study said:

"We can't expect people to move home to avoid air pollution - Governments and public bodies must be acting right now to make all areas safe and protect the population from these harms.

"What is particularly worrying is that the levels of air pollution, particularly PM2.5, at which this study saw people with heart remodelling are not even deemed particularly high by the UK Government - this is why we are calling for the WHO guidelines to be adopted. They are less than half of UK legal limits and while we know there are no safe limits for some forms of air pollution, we believe this is a crucial step in protecting the nation's heart health.

The experts may recommend changes in safety limits of Air Pollutants in the wake of present study.