Research
Living in most polluted areas increases risk of heart failure by a quarter
People in the most polluted areas could be 27 per cent more likely to develop heart failure, based on new UK research funded by the British Heart Foundation and presented at the European Society of Cardiology’s annual congress in Madrid.
The study looked at PM2.5, a pollutant released from sources including vehicles, industry and household heating. These particles are 30 times smaller than the width of a human hair, making them small enough to get into the bloodstream after being inhaled.
Researchers analysed data from the UK Biobank health study, looking at average levels of PM2.5 in the areas where 299,323 people lived.
They then investigated rates of strokes and heart failure in the same people over a decade.
Those living in the worst 10 per cent of areas for PM2.5 pollution had a 27 per cent higher risk of developing heart failure, compared to people in the best 10 per cent of areas for PM2.5 pollution. The risk of having a stroke was seven per cent higher for those in the worst areas.
Based on the study’s figures from 2010, the most polluted areas in the UK pumped out an extra 3.7 micrograms of PM2.5 per cubic metre of air, compared to the least polluted areas in an average year.
For every extra one microgram in an area where people lived, the risk of developing heart failure rose by seven per cent and the stroke risk increased by three per cent.
People exposed to more PM2.5 also tended to have a smaller left ventricle - the main pumping chamber of the heart. The researchers suggest this is typical of an 'older heart'.
Ghita Housni, PhD student at the William Harvey Research Institute, within Queen Mary University of London, said:
“We know cleaner air means healthier hearts, and this research lays bare the impact of air pollution on public health. Reducing your exposure to air pollution is a crucial part of preventing heart conditions in the modern age and lowering your risk of heart failure and stroke. We need to improve air quality by introducing public health strategies which strongly prioritise cardiovascular protection.”
Because PM2.5 does not belong in the body, when it's breathed in, the immune system overreacts to cause inflammation. When blood vessels become inflamed, they become stiffer and more prone to fatty build-up. This can cause high blood pressure, which raises the risk of having a stroke. The heart also has to work harder to pump blood through inflamed blood vessels, which over time can make it become weaker, and develop heart failure.
After taking into account factors that affect stroke risk, such as age and smoking, researchers found only a small proportion of people in the study had a stroke. It is estimated that only one extra person in every 100 experienced a stroke in the top ten per cent of polluted areas, compared to the areas with least pollution. Only an extra two people in every 100 developed heart failure.
Rates of heart failure and stroke are likely to have been higher for people analysed in the study, as they were all over 40, and stroke risk increases with age.
Researchers found no significant link between pollution and heart attacks.
The team analysed data without looking at specific places, so the results cannot reveal which locations in the UK may raise the risk of residents developing heart failure or having a stroke.
Next, the team hope to investigate how air pollution affects those already living with cardiovascular disease, who may be more vulnerable.
PM2.5 pollution levels have significantly fallen in the UK since they were measured for the study, and are within Government targets, but experts say the risk of heart failure and stroke in polluted areas is still a concerning health risk.
Dr Sonya Babu-Narayan, Clinical Director at the British Heart Foundation, said:
“We know there are no safe levels of air pollution. These early findings linking high PM2.5 levels to heart failure add to a growing body of evidence that poor air quality is damaging to our hearts.
"It’s good to know that the kind of PM2.5 levels experienced by the people in this study have already improved since the introduction of Government targets in 2021. Nevertheless, these levels still exceed World Health Organisation guidelines. Going further to reduce air pollution could help the UK to prevent premature cardiovascular disease, and save and improve lives for current and future generations.”