Air pollution causes major changes in the heart’s structure

A new study from the British Heart Foundation (BHF) has revealed that exposure to low levels of air pollution can cause major structural changes to the heart that are similar to those associated with the early stages of heart failure.

A team of scientists at Queen Mary University of London analyzed data from around 4,000 individuals in the UK Biobank study. For this research, participants had reported on their lifestyles, health, and where they lived. Magnetic resonance imaging (MRI) was used to measure the size, weight, and function of the participants’ hearts at fixed times.

Furthermore, the researchers eliminated all participants who had moved during the study or had underlying heart problems.

The experts found a clear association between individuals who were exposed to nitrogen dioxide (NO2) or fine particulate matter (PM2.5) and the development of larger right and left ventricles in the heart. Although the participants were healthy and showed no symptoms, the same restructuring of the heart is seen in the early stages of heart failure.

In addition, exposure to higher levels of the pollutants was linked to more extreme changes in the heart. For example, the heart was found to be enlarged by an additional one percent for every 1 extra μg per cubic meter of PM2.5 and for every 10 extra μg per cubic meter of NO2.

“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,” said study lead author Dr. Nay Aung.

Air pollution has become the biggest environmental risk factor linked to deaths across England. In addition, coronary heart disease and stroke account for 58 percent of deaths related to outdoor air pollution globally.

Professor Jeremy Pearson is an associate medical director at the BHF.

“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.”

Dr. Aung said: “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.”

The study is published in the journal Circulation.

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By Chrissy Sexton, Earth.com Staff Writer