Air pollution and Risk of Stroke.





Related Monographs

Consumer Data: Stroke
Professional Data: Stroke


The term "stroke" or "paralytic stroke" is commonly used to describe a sudden problem with the brain that is usually related to its blood supply. A "stroke," therefore, can be due to ischemia (decreased blood supply), infarction (interrupted blood supply), or hemorrhage (severe bleeding), and usually means that there is some kind of permanent problem with the nervous system.1 All three of these causes (ischemia, infarction, or hemorrhage) would be due to cerebrovascular disease (disease related to the blood supply to the brain).

Hyperlipidemia and hypercholesterolemia (increased cholesterol and fats in the blood) are risk factors for the development of atherosclerosis, which increases the risks of both coronary heart disease and stroke. Another major risk factor for both ischemic and hemorrhagic stroke is cigarette smoking. Smokers have two to three times the risk of stroke compared with non-smokers, and a fourfold to six fold increase in stroke risk compared with those who have never smoked.2

A recent study stated that there is a known correlation between cardiovascular disease and air pollution, but little is know about the risk of stroke. This study was conducted in Korea over a 7-year period. Both ischemic and hemorrhagic stroke deaths were examined. The results showed that in the case of ischemic stroke deaths, there was a link to air pollution. For hemorrhagic stroke, there was no association between the two. Some of the air pollutants found to increase the risk were sulfur dioxide, nitrogen dioxide, and carbon monoxide, which are prevalent in air. The authors of this study concluded that, "these findings indicate that air pollutants are significantly associated with ischemic stroke mortality, which suggests an acute pathogenetic process in the cerebrovascular system induced by air pollution."3


1. Welty TE. Cerebrovascular Disease, In: Koda-Kimble MA, Young LY, eds. Applied Therapeutics. 5th ed. Vancouver, WA: 1992;14:1-7.
2. Donnan GA, McNeil JJ, Adena MA, et al. Smoking as a risk factor for cerebral ischemia. Lancet. 1989;II:643-647.
3. Hong YC, et al. Air Pollution. A New Risk Factor for Ischemic Stroke Mortality. Stroke. Sep 2002;33:2165.