To add to our growing coverage of research that links common forms of air pollution with various diseases and cognitive problems, new research from the William Harvey Research Institute at Queen Mary University of London has linked exposure to PM 2.5 (fine particulate matter air pollution) to heart damage.
The new research notes, though, that the observed harmful changes to heart structure and function seem to be protected against to a degree by the possession of a degree-level education — presumably because such people aren’t working in conditions with high levels of exposure, and because of access to better nutrition/food, lower stress living environments, etc.
“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,” states lead author Dr. Nay Aung, a cardiologist and Wellcome Trust research fellow at William Harvey Research Institute at Queen Mary University of London, UK. “This appears to be driven by an inflammatory response — inhalation of fine particulate matter (PM 2.5) causes localised inflammation of the lungs followed by a more systemic inflammation affecting the whole body.”
The press release provides more: “The study included 4,255 participants from the UK Biobank, a large community-based cohort study. Cardiac magnetic resonance imaging was conducted to measure left ventricular volume (structure) and left ventricular ejection fraction (function). Annual average exposure to PM 2.5 was calculated based on participants’ home address.
“The association between PM 2.5 exposure and heart structure and function was estimated using multivariable linear regression, a form of statistical modelling which adjusts for potential factors that could influence the relationship such as age, gender, diabetes, and blood pressure.
“Participants were 62 years old on average and 47% were men. The annual average PM 2.5 level was 10 µg/m3. The investigators found linear relationships between ambient PM 2.5 level and heart structure and function. Every 5 µg/m3 increase in exposure was associated with a 4-8% increase in left ventricular volume and a 2% decrease in left ventricular ejection fraction.”
So, it’s a significant association, in other words.
As explained by Dr. Aung: “We found that as PM 2.5 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.”
As regards the mechanisms involved, Dr. Aung simply commented that exposure to particulate matter air pollution results in systemic inflammation, vasoconstriction, and heightened blood pressure levels — all of which can increase the pressure in the heart, and result in enlargement (in order to deal with the overload), and thus a reduction in contractile efficiency.
Dr. Aung continued: “We found that the average exposure to PM 2.5 in the UK is about 10 µg/m3 in our study. 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.”
That’s a very interesting point to make. Much recent research has seemed to expose the fact that “safe” air pollution limits seem to in actual practice be nothing of the sort — there are clearly very negative effects on human health and cognition occurring even with what seem, to conventional knowledge, to be minimal levels of exposure.
Dr. Aung concluded: “Our results suggest that PM 2.5 is linked with negative changes in the heart structure and function that are associated with poor outcomes. Reducing PM 2.5 emission should be an urgent public health priority and the worst offenders such as diesel vehicles should be addressed with policy measures.
“Avoid times and places where there is a high level of pollution. If you want to cycle into work and there is heavy traffic around that time then try to find a quieter route. Walk on the part of the pavement furthest from cars to reduce the amount of pollution you breathe in. Those with cardiorespiratory diseases should limit the time spent outdoors during highly polluted periods such as rush hours.”