ORLANDO — Adult-onset asthma was linked to an almost twofold increased rate of coronary heart disease or stroke in women in a study with more than 15,000 people.
The mechanism behind this association is unknown but may be explained by an increased level of systemic inflammation in women with adult-onset asthma, Stephen Onufrak and his associates reported in a poster at a conference on cardiovascular disease epidemiology and prevention sponsored by the American Heart Association.
Prior findings from other studies also supported links between asthma and atherosclerotic events, and showed that the association was strongest in women, said Mr. Onufrak, an epidemiologist at Emory University, Atlanta.
The study used data collected from 15,573 white and black persons who were enrolled in the Atherosclerosis Risk in Communities (ARIC) study during 1987–1989. The group included nearly 7,000 men, of whom 6,594 had no asthma, 227 had asthma that began during childhood, and 146 who had adult-onset asthma. Also included were more than 8,600 women, with 8,093 who had no asthma, 214 who had childhood-onset asthma, and 299 whose asthma started after they were adults.
For this analysis, childhood asthma was defined as having its onset before age 21, and adult-onset asthma was defined as appearing at age 21 or after.
The researchers then analyzed the rates of incident coronary heart disease or stroke during 12–14 years of follow-up based on asthma prevalence at baseline. The hazard ratios were adjusted to account for baseline differences in several demographic and clinical variables, including age, race, body mass index, smoking history, hypertension, serum lipid levels, and physical activity.
The analyses showed that women with adult-onset asthma were 70% more likely to develop coronary artery disease and 79% more likely to have stroke, compared with women without asthma. Both of these differences were statistically significant. No significant change was seen in the hazard ratios for coronary heart disease or stroke, compared with people with no asthma, among women who had childhood asthma or among men with either adult-onset or childhood asthma. (See box.)
Another analysis focused just on the men and women who had never smoked. Again, women with adult asthma had a statistically significant twofold increased risk of coronary heart disease or stroke, compared with women without asthma. No significant differences in outcome rates were seen in women with childhood asthma or among men, the researchers reported.
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