A study led by Queen Mary University of London has shown that people exposed to levels of air pollution that are well within UK guidelines have structural changes in the heart that are similar to the remodeling seen in the early stages of heart failure.
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As reported in the journal Circulation, Professor Steffen Petersen and colleagues studied data available for approximately 4,000 participants in the UK Biobank study who provided information on their lifestyle, health history and residential location.
They also had their blood tested and underwent health scans including an MRI scan to measure heart size, weight and function.
Although most participants did not live in major cities, a clear association was observed between living near busy roads and exposure to nitrogen oxide (NO2) or PM2.5 (small air pollution particles) and the development of larger heart ventricles, structural changes that are also seen in the early stages of heart failure.
The higher the level of exposure to the pollutants, the more significant the structural changes were. For every 10 additional μg per cubic metre of NO2 and every additional 1 μg per cubic metre of PM2.5, the increase in heart size was about 1%.
Worryingly, the average annual exposure to PM2.5 was 8 to 12μg per m3, which is well within the UK government’s guideline of 25μg per m3. The World Health Organisation (WHO) guideline is 10ug per m3.
The average annual exposure to NO2 was 10-50μg per m3, which is approaching and above both the WHO and the UK government guidelines of 40μg per m3.
The British Heart Foundation, which part-funded the study, wants to ensure that the public's heart and circulatory health is key to discussions taking place ahead of the UK Government’s consultation on their draft Clean Air Strategy, which closes on 14th August.
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.”
Jeremy Pearson, Associate Medical Director, The British Heart Foundation