May 26 (UPI) -- Researchers at Queen Mary University in London have found significant evidence that particulate matter form diesel pollution can cause heart damage.
"There is strong evidence that particulate matter [PM] emitted mainly from diesel road vehicles is associated with increased risk of heart attack, heart failure, and death," Dr. Nay Aung, a cardiologist at the William Harvey Research Institute, Queen Mary University of London, said in a press release. "This appears to be driven by an inflammatory response -- inhalation of fine particulate matter [PM2.5] causes localized inflammation of the lungs followed by a more systemic inflammation affecting the whole body."
PM2.5 causes systemic inflammation, vasoconstriction and raised blood pressure, which when combined puts increased pressure on the heart. The result is an enlarged heart to cope with the overload, which reduces the contractile efficiency leading to a reduction of function.
The study was conducted on 4,255 participants with an average age of 62 from the UK Biobank, a large community-based cohort study.
Cardiac MRI was used to measure left ventricular volume or structure and left ventricular ejection fraction or function in patients exposed to PM2.5.
The PM2.5 exposure was calculated based on study participants' home addresses.
"We found that as PM2.5 exposure rises, the larger the heart gets and the worse it performs. Both of these measures are associated with increased morbidity and mortality from heart disease," Aung said.
The study found that people with degree-level education were less prone to having a larger heart and had a smaller reduction in ejection fraction when exposed to PM2.5 than those with lower levels of education.
"People who were highly educated were less likely to have harmful effects on the heart from pollution," Aung said. "This could be due to a number of factors including better housing and workplace conditions, which reduce pollution exposure. Educated people may also be more aware of their health, have healthier lifestyles, and have better access to healthcare."
The annual average PM2.5 level was 10 μg/m3. The investigators found linear relationships between ambient PM2.5 level and heart structure and function. Every 5 μg/m3 increase in exposure was associated with a 4 to 8 percent increase in left ventricular volume and a 2 percent decrease in left ventricular ejection fraction.
"We found that the average exposure to PM2.5 in the UK is about 10 μg/m3 in our study," Aung said. "This is way below the European target of less than 25 μg/m3 and yet we are still seeing these harmful effects. This suggests that the current target level is not safe and should be lowered. Our results suggest that PM2.5 is linked with negative changes in the heart structure and function that are associated with poor outcomes. Reducing PM2.5 emission should be an urgent public health priority and the worst offenders such as diesel vehicles should be addressed with policy measures."
The study was presented at EuroCMR 2017.1.