Myocardial infarctions in Berlin are significantly more common on days with high nitric oxide concentrations.
Air pollution may cause heart attacks in nonsmokers
Air pollution is known to cause and worsen a wide range of adverse health conditions from pulminary ailments like asthma to mental problems like depression. It can cause learning disabilities in children and even affect the workings of our genes.
In the United States alone tens of thousands of people die each year of health conditions linked to air pollution while millions of lives are lost prematurely to toxic air worldwide.
And there is worse news: air pollution can lead to heart attacks in nonsmokers, according to scientists at the European Society of Cardiology who examined the effects of toxic air on cardiovascular health.
Specifically, the researchers investigated the links between airborne nitric oxide content and the incidence of myocardial infarction in Berlin. Nitric oxide primarily comes from diesel vehicles in the city where it is also a source of PM10 pollution. Abrasion from brakes and tyres also contribute to PM10.
In the study nearly 18,000 patients with a myocardial infarction between 2008 and 2014 were examined according to variables such as sex, age and smoking status. At the same time, the scientists looked at daily PM10 and nitric oxide concentrations in Berlin along with daily weather profiles to see if there was a correlation between the incidence of myocardial infarctions and higher air pollution.
The scientists found that “myocardial infarction was significantly more common on days with high nitric oxide concentrations, with a 1% higher incidence for every 10 µg/m3 increase,” as they report.
“Myocardial infarction was also more common when there was a high average PM10 concentration over the three preceding days, with a 4% higher incidence for every 10 µg/m3 increase,” they add.
However, smokers appeared unaffected by increased air pollution.
“The correlation between air pollution and heart attacks in our study was absent in smokers,” explains Dr. Insa de Buhr-Stockburger, a scientist at Berlin Brandenburg Myocardial Infarction Registry who led the research. “This may indicate that bad air can actually cause heart attacks since smokers, who are continuously self-intoxicating with air pollutants, seem less affected by additional external pollutants.”
In another finding, myocardial infarctions were related to the air temperature with a 6% lower incidence for every 10°C rise while sunshine and precipitation did not seem to have an effect.
“[D]irty air is a risk factor for acute myocardial infarction and more efforts are needed to lower pollution from traffic and combustion. Causation cannot be established by an observational study [but] it is plausible that air pollution is a contributing cause of myocardial infarction, given that nitric oxide and PM10 promote inflammation, atherosclerosis is partly caused by inflammatory processes, and no associations were found in smokers,” Dr. de Buhr-Stockburger notes.
