Adults with late-onset asthma had a significantly increased risk of cardiovascular disease events such as MI, stroke and heart failure compared with those who did not have asthma even after adjusting for age, sex and cardiovascular disease risk factors.

After more than 13 years of follow-up, participants with late-onset asthma had a 1.6- fold higher rate of cardiovascular disease events events compared with non-asthmatics. The researchers defined late-onset asthma as an asthma diagnosis at age 18 or older.

Lead researcher Matthew C. Tattersall, DO, MS, of the University of Wisconsin School of Medicine and Population Health, and colleagues published their results online in the Journal of the American Heart Association on Aug. 24.

More than 25 million adults in the U.S. have asthma, according to the researchers. They added that asthma and cardiovascular disease shared an underlying inflammatory pathophysiology.

This longitudinal cohort study, known as the Wisconsin Sleep Cohort, has prospectively followed adults since 1988 and evaluated their sleep, respiratory and cardiovascular outcomes. The participants were selected from a random sample of payroll records of state of Wisconsin employees who were between 30 and 60 years old.

For this analysis, the researchers examined 1,269 adults who had not experienced a cardiovascular disease event at baseline. They conducted baseline visits between July 1989 and April 2003 and followed the participants through December 2013.

At baseline, the mean age of participants was 47.3 years old, while 46 percent were female and 13.1 percent had asthma, including 8.8 percent with late-onset asthma and 4.3 percent with early-onset asthma. They considered early-onset asthma as an asthma diagnosis before age 18.

The mean age of asthma diagnosis was 39.5 years old in the late-onset group and 8.9 years old in the early-onset group. In addition, adults with late-onset asthma were more likely to be female, take antihypertensive medications and have a higher body mass index compared to people without asthma.

After a mean follow-up period of 13.9 years, there were 223 cardiovascular events: 179 in the non-asthma group, 22 in the late-onset asthma group and 7 in the early-onset group. The researchers defined cardiovascular disease events as the occurrence of coronary death, MI, angina, stroke, coronary revascularization, heart failure or cardiovascular disease death. They identified cardiovascular events through health history questionnaires during follow-up visits and mailed health surveys.

The 10-year cardiovascular disease-event incidence rates were 12.7 percent for adults with late-onset asthma, 8.9 percent for the non-asthma group and 3.8 percent for the early-onset asthma group.

After adjusting for age, sex and cardiovascular disease risk factors, adults with late-onset asthma were 57 percent more likely to have a cardiovascular event compared with adults who did not have asthma. Meanwhile, adults with early-onset asthma had no difference in cardiovascular events compared with non-asthmatics.

The researchers cited a few potential limitations of the study, including that asthma was a self-reported physician diagnosis. Participants also self-reported their age when they were diagnosed with asthma. In addition, the researchers had no objective measures of asthma severity. Further, this was an observational study, so the associations between late-onset asthma and cardiovascular events do not confirm causation.

“Late-onset, but not early-onset asthma, was associated with an increased risk of [cardiovascular disease] events in this prospective observational study with over a decade of follow-up,” the researchers wrote. “Given the public health burden of asthma, further investigations into the mechanisms of this association in specific asthma phenotypes are needed.”