Analysis now shows that heart attacks are more common at high levels of every main pollutant except ozone. Is the problem of air pollution being taken seriously?
Studies have shown that an increase in air pollution has been linked to a decrease in lung function, according to The World Health Organisation (WHO) air pollution causes 2million premature deaths annually.
Researchers from the Paris Cardiovascular Research Centre, led by Harzrije Mustafic, have found that heart attacks were slightly more common at high level of every main pollutant except ozone.
Reporting in the Journal of the American Medical Association, they looked at 34 studies, comparing the risk of suffering a heart attack or myocardial infarction (interruption of blood supply to the area) at various levels of inhaling industrial and traffic-related pollutants.
The reports included anywhere from 400 to 300,000 people, with heart attacks that were confirmed in hospital records and disease or death registries.
All the main air pollutants, with the exception of ozone, were significantly associated with a near-term increase in myocardial infarction risk,researchers said.
Research was also carried out by the University of Michigan (U-M), studies there showed that inhaling air pollution over a time period of just two hours, caused a significant increase in diastolic blood pressure, the lower number on blood pressure readings.
For most pollutants, an increase in concentration of 10 micrograms per cubic metre of air – the typical standard used to asses harm and barely noticeable to the person breathing the air – was associated with a 1-3% increase in the chances of having a heart attack the following week.
According to Harzrije Mustafic, when inhaling polluted air, small particles can reach the tiny sacs in the lungs and then be carried in the bloodstream to the heart. Blood vessels ability to expand and contract can also be affected, an effect that researchers say make high-pollution days go hand in hand with a person’s risk of having a stroke.
Even if the relative risks are low compared with traditional risk factors such as smoking status or hypertension or diabetes, in fact everybody is exposed to air pollution in industrialised countries, so even small effects can add up.
Can moderate air pollution increase the risk of strokes?
Sanjay Rajagopalan, a researcher at The Ohio State University in Columbus said:
If you put together the evidence, clearly day-to-day changes in particle concentration do make a very small but significant difference in terms of increasing susceptibility for cardiovascular events.
This seems to be particularly for individuals with pre-existing heart disease.
Air pollution, even at levels generally considered safe by federal regulations, increases the risk of stroke by 34 percent, Beth Israel Deaconess Medical Center researchers have found.
Considering that almost everyone is exposed to air pollution and is at risk for stroke, that’s actually a pretty large effect,
says Gregory Wellenius, ScD, the study’s lead author and an Assistant Professor of Community Health at Brown University.