How does air pollution affect health?
Increasing air pollution threatens the health of millions of people worldwide. Researchers have now found that air pollution is even associated with changes in the structure of the heart, as can be seen in early stages of heart failure.
In their latest study, scientists at Queen Mary University of London found that global air pollution is linked to changes in the structure of the heart. The doctors published the results of their study in the English-language journal "Circulation".
What problems does air pollution cause?
The findings of the new investigation could help explain the increased number of deaths in areas with high levels of air pollution, experts say. A study from last year, for example, showed that people in the UK die 64 times more often from air pollution than people in Sweden. Such premature deaths can be linked to a number of causes, including respiratory problems, stroke, and coronary artery disease.
Unfortunately, the causes were still unknown
However, what is not known is the mechanism behind why air pollution leads to an increased risk of heart attack and stroke, explains study author Dr. Nay Aung from Queen Mary University of London. The latest study helps solve this mystery. Exposure to nitrogen dioxide and particulate matter, known as PM2.5 and PM10 particles, is associated with an increase in the size of two ventricles.
Almost 4,000 subjects were examined
The authors add that similar changes can affect heart performance and are often observed before onset of heart failure. The team used data from almost 4,000 volunteer participants for the study. These subjects were between 40 and 69 years old and were free of cardiovascular diseases at the beginning of the study.
Concentration of pollutants at the place of residence was taken into account
MRI scans of the heart were decisive, which provided detailed images of the structure and function of the heart. The study also included estimates of the outside concentrations of various pollutants at the participants' homes, which were made about five years before the scan. After checking factors such as age, gender, income and smoking habits, the team found that higher exposure to PM2.5 particles, PM10 particles and nitrogen dioxide were associated with a larger volume of the right and left ventricles, respectively.
Increasing ventricle size is an early warning sign of heart failure
The size of the identified effect is small, but still important, says Dr. Aung. This effect size is comparable to other known cardiac risk factors such as high blood pressure. It was also found that the heart size increased with increasing blood pressure. Although the increase in ventricle size was small in this study, it is an early warning that the increased risk of heart failure could explain why people who are at higher levels of pollution. If the ventricles become larger, this indicates that the heart is under stress. If such changes are not treated or reversed, the heart can fail in the long run. Dr. Aung said the study found that an increase in exposure to PM2.5 of 1 μg / m3 was related to an increase in the size of each ventricle of just under 1 percent. He stressed that the results were very worrying as most of the participants lived in areas with relatively low levels of air pollution.
Air pollution in some areas is well above the limit
On average, the participants were exposed to PM2.5 concentrations of 8-12 μg per cubic meter, which are close to the threshold value of 10 μg / m³ recommended by the WHO. Research from last year showed that in some polluted areas, such as central London, the average PM2.5 concentration was above 18 μg / m3, with values increasing even more on days with poor pollution. Previous studies have also shown that mice exposed to high concentrations of PM2.5 develop larger left ventricles, the authors explain.
Stricter air quality standards are needed
The results of the study are worrying because they show the serious health effects of air pollution, even if it is still far below the applicable legal limits. More stringent and binding air quality standards are needed, which reflect the latest scientific knowledge and help protect people from the serious damage that air pollution causes to health, doctors add. (as)