New study finds possible link between asthma and stroke

• While asthma does not seem to increase the risk of developing coronary heart disease, it may be a risk factor for stroke, researchers report.
• A. R. Folsom from the University of Minnesota, Minneapolis, and colleagues used data from the Atherosclerosis Risk in Communities (ARIC) study to investigate the possible association between asthma, coronary heart disease and stroke.
• Regardless of whether participants had asthma now or at some point in the past or never, their rates of coronary heart disease were not affected, the researchers report in the medical journal Thorax.
• In fact, asthma in men was associated with a lower incidence of coronary heart disease after taking account of major cardiovascular risk factors.
• In contrast, the team found, ever having had asthma was associated with a 65 percent higher risk of stroke than never having had asthma.
• The risk with current asthma was somewhat higher, a 93 percent increase.
• "If this observed association is causal," Folsom and colleagues write, "it adds to the significant burden that is imposed by asthma, a highly prevalent condition in the general population."
• It is unclear "why asthma might increase the risk of stroke but not of coronary heart disease," the investigators write.
• "The biological mechanisms by which subjects with asthma may have an excess risk of stroke require further study," they conclude.