Cardiovascular Events May be Directly Linked to Air Pollution

An increased risk for developing blood clots in the lung and an irregular heartbeat may be linked to air pollution, according to a recent study.

Researchers maintain that the evidence that ties air pollution to the direct impact of heart attack or stroke is still unclear. However, it suggests that there are specific air pollutants that increase the risk of cardiovascular events.
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Investigators used data from 3 national collections from 2003 to 2009 in England and Wales. The data follows hospital statistics for emergency admissions, hospital admissions for heart attack and stroke, and the figures from the Office of National Statistics on recorded deaths.

The data included over 400,000 myocardial infarction (MI) events, over 2,000,000 emergency admissions for cardiovascular events, and over 600,000 deaths for a period of 5 days; all were linked to daily average concentrations of nitrogen dioxide, carbon monoxide, sulfur dioxide, ozone, and particulate matter (PM10 and PM2.5). 

In terms of mortality, no cardiovascular disease (CVD) analysis showed clear association with any of the pollutants except for PM2.5 in the case of atrial fibrillation, pulmonary embolism, and arrhythmias.

Researchers discovered that only nitrogen dioxide was linked to an increased risk of CVD in hospital admissions: 1.7% (95% CI 0.9 to 2.6). Additionally, the study found arrhythmias 2.9% (0.6 to 5.2), atrial fibrillation 2.8% (0.3 to 5.4), non-MI heart failure 4.4% (2.0 to 6.8) and heart failure 4.4% (2.0 to 6.8) for a 10th–90th centile increase.

Moreover, nitrogen dioxide was associated with an increased risk of myocardial infarction; it pertained to non-ST-elevation myocardial infraction 3.6% (95% CI 0.4 to 6.9).

“We found some evidence of irregular heart beat including atrial fibrillation, but not clear on severe heart attack and stroke. This suggests that pollution effects observed here may in part be mediated by non-thrombosis pathways, although, it could be multiple pathways,” said Ai Milojevic MD, the study’s lead researcher.

“What is particularly important is that we found elderly people and hospital patients with chromic IHD or arrhythmias are observed to be at particular risk which could help inform intervention strategies,” he said.

The full study was published in the June issue of Heart.

-Michelle Canales

Reference:

Milojevic A, Wilkinson P, Armstrong B, et al. Short-term effects of air pollution on a range of cardiovascular events in England and Wales: case-crossover analysis of the MINAP database, hospital admissions and mortality. Heart. 2014 June 4 [epub ahead of print] doi:10.1136/heartjnl-2013-304963