Cardiologists from Harvard and Boston tell us that fine particle air pollution stimulates the production of inflammatory cells in the bone marrow, causing inflammation of the arteries, which promotes the development of cardiovascular disease.
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Identification of the process linking pollution to cardiovascular events
This retrospective study followed 503 patients without cardiovascular disease or cancer for more than 4 years who had undergone MGH imaging tests for various medical reasons. Scientists estimated the average annual fine particle levels to which these participants were exposed, using data from the US Environmental Protection Agency’s air quality monitors.
- During follow-up, 40 people experienced major cardiovascular events, including heart attacks and strokes (strokes);
- the highest risk is observed in participants with higher levels of fine particles around their home;
- this increased risk associated with fine particle levels remains significant even after taking into account possible confounding factors (other cardiovascular risk factors in particular but also socio-economic factors);
- imaging tests also show, in these more exposed participants, higher bone marrow activity, suggesting increased production of inflammatory cells (a process called leukopoiesis) and high arterial inflammation;
- further analyzes reveal that leukopoiesis in response to exposure to air pollution is a trigger for arterial inflammation.
This pathway, linking air pollution to cardiovascular events through higher bone marrow activity and arterial inflammation, represents 29% of the relationship between pollution and cardiovascular disorders, say the researchers,
which suggests new therapeutic targets beyond pollution mitigation to reduce the cardiovascular impact of pollution.
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