Rapid increases in pollution may be as harmful to the heart as sustained high levels, according to new research published in the European Journal of Preventive Cardiology.
Previous BHF research has shown that long-term exposure to air pollution leads to inflammation in the blood vessels, including those supplying the heart, and promotes the build-up of fatty plaques in the linings of blood vessels, which can eventually lead to a heart attack or stroke.
This new study investigated whether rapid increases in pollution increase the risk of heart attack. It also looked at whether an association between heart attacks and changes in air pollution exists in “clean air cities”, where concentrations of air pollution vary but do not exceed EU limits.
The study was conducted in Jena, Germany, a city with 100,000 residents where concentrations of some air pollutants exceeded EU daily limits on only a handful of days over the last few years. All heart attack patients living within 10km of Jena, and who were admitted to Jena University Hospital between 2003 and 2010, were included.
The study consisted of 693 patients. The concentrations of air pollutants one, two, and three days before heart attack symptoms arose were compared to concentrations in both the previous and following weeks. The researchers found that increases of nitric oxides of more than 20 μg/m3 within 24 hours of symptoms were associated with a more than doubled risk of heart attack.
Commenting on the study Professor Metin Avkiran, Associate Medical Director at the British Heart Foundation, said:
"This study further highlights the daily danger that people face from breathing dirty air. We already know that air pollution, including various gases and small particles, contributes to an estimated 40,000 premature deaths in the UK each year. This research indicates that even temporary increases in nitrogen dioxide levels may elevate the risk of having a potentially fatal heart attack.
"If confirmed by larger studies, this is likely to reshape thinking around the impact of air pollution on heart health, to take into account the importance of sharp increases in pollution levels. We also need research to determine how a temporary increase in nitrogen dioxide levels might trigger a heart attack.
"There is now a wealth of evidence which clearly demonstrates the harm air pollution causes. Adopting the World Health Organisation’s air quality guidelines would help ensure the nation’s heart health is better protected from the potential risks they pose.”
Read more about how air pollution causes heart disease