Air Pollution and Stroke

Abstract

The adverse health effects of air pollution have long been recognised; however, there is less awareness that the majority of the morbidity and mortality caused by air pollution is due to its effects on the cardiovascular system. Evidence from epidemiological studies have demonstrated a strong association between air pollution and cardiovascular diseases including stroke. Although the relative risk is small at an individual level, the ubiquitous nature of exposure to air pollution means that the absolute risk at a population level is on a par with "traditional" risk factors for cardiovascular disease. Of particular concern are findings that the strength of this association is stronger in low and middle income countries where air pollution is projected to rise as a result of rapid industrialisation. The underlying biological mechanisms through which air pollutants exert their effect on the vasculature are still an area of intense discussion. A greater understanding of the effect size and mechanisms is necessary to develop effective strategies at individual and policy levels to mitigate the adverse cardiovascular effects of air pollution.

Keywords: Air pollution; Cardiovascular diseases; Public health; Stroke.

Figure 1.

Population attributable risk of cerebrovascular disease associated with air pollution worldwide. Estimates from Institute for Health Metrics and Evaluation (IHME).

Figure 2.

Association between air pollutants and hospitalisation or mortality from stroke. Adapted from Shah et al. [5]. CI, confidence interval; PM_2.5, particulate matter diameter of 2.5 µm or less; PM₁₀, particulate matter diameter of 10 µm or less; CO, carbon monoxide; ppm, part per million; SO₂, sulphur dioxide; ppb, part per billion; NO₂, nitrogen dioxide; O₃, ozone.