"Safe" Air Pollution Increases Cardiovascular Risk

Particulate matter and nitric dioxide (NO2) air pollution at levels within the limits recommended by the European Union have been linked to an increased risk of severe heart attack. Dr Jean-Francois Argacha, a cardiologist at University Hospital Brussels (Belgium), and colleagues investigated the effects of particulate matter and NO2 air pollution on the risk of ST-segment elevation myocardial infarction (STEMI). STEMI are caused by the thrombotic occlusion of a coronary artery, and have the worst prognosis of all infarctions. Data showed that between 2009 and 2013, there were 11,428 hospitalisations for STEMI in Belgium. Analysis of this data crossed-over with that of data on air pollution revealed that 10 μg/m3 increases in ambient fine particulate matter (PM2.5) concentrations were associated with a 2.8% increase in STEMI, while 10 μg/m3 rises in NO2 were associated with a 5.1% increased risk. However, these associations were only observed in men. The authors believe that this may be because women were underrepresented in the study; however they note that previous studies have demonstrated that blood pressure, arterial stiffness and heart rate variability abnormalities secondary to air pollution exposure are more pronounced in men. "The association between STEMI and air pollution was observed within one day of exposure," said Dr Argacha. “We found that particulate and NO2 air pollution, at levels below European limits, are associated with an increased risk of STEMI. The detrimental impact of NO2 exceeds that of fine particles and raises new public health concerns."