Environmental factors, particularly air pollution, increases risk of myocardial infarction

Exposure to air pollutants increases the risk of fatal myocardial infarction (MI), particularly pollutants caused by motor traffic. This is the conclusion of a new thesis published by Karolinska Institutet.

Cardiovascular diseases are the most common cause of death in Sweden and other Western European countries. Known risk factors include age, gender, hereditariness, smoking, hypertension and high blood lipid levels. However, the part played by the external environment still remains something of a mystery. Exposure factors that are thought to compound the risk include passive smoking, air pollution, noise pollution and the chemical composition of drinking water. Even if such environmental factors give only a small increase in risk, they can have serious consequences for public health bearing in mind the prevalence of the disease and their widespread and indiscriminate affect on people.

The new thesis presents the results of Mats Rosenlund’s research into environmental factors like aircraft noise, passive smoking, drinking water quality, and air pollution.

The study of the relationship between air pollution and cardiovascular disease suggests that a prolonged exposure to ambient air pollutants increases the risk of fatal MI, especially outside the hospital. The relationship was particularly salient for airborne pollutants caused by motor traffic. However, there was no impact on the risk of suffering incapacitating or non-fatal MI. To obtain the necessary pollution data, each subject’s home address was converted to geographical coordinates, which were then cross-referenced with data on all known sources of pollutant emission since 1960.

According to the results of the study of the hardness of the drinking water, there is no evidence that the hardness of the water or its magnesium or calcium content has any effect on the risk of MI.

The thesis also included previously published studies that suggest that a correlation exists between hypertension and aircraft noise, the latter calculated as either “aircraft noise levels” over 55 dBA or as maximum aircraft noise peaks of over 72 dBA.

Studies were also conducted that corroborate previous claims that passive smoking increases the risk of MI. The results suggest that combined exposure at home and at work and the aggregate exposure during adulthood contribute significantly to the risk of MI.