MADISON, Wis., Aug. 24 (UPI) -- Although doctors have theorized links between asthma and cardiovascular disease, new research suggests patients with late-onset asthma are especially at risk for heart disease and stroke.
Patients with adult-onset asthma are at significant risk for developing cardiovascular disease, suggesting links between the inflammation caused by both conditions combines for a greater health risk, researchers at the University of Wisconsin report in the Journal of the American Heart Association.
Researchers at UW have been exploring the link between the two conditions for several years, with the new study seeking a subtype of asthma with greater risk for cardiovascular disease -- arriving at the harder to treat adult version of asthma.
Some clinicians consider patients as young as 12 who develop asthma to be late onset, while others consider age 18, according to Dr. Matthew Tattersall, an assistant professor of medicine and cardiologist at the University of Wisconsin School of Medicine.
"Onset asthma tends to be more difficult to treat -- it resists steroid treatments sometimes -- and we really don't know why," Tattersall told UPI in a phone interview, adding the link between asthma and heart disease is not understood, aside from the new study confirming a link.
"The two conditions share inflammation, but more research is needed to understand it," he said. "Our thinking is the chronic low-level inflammation in one relates to the other.
For the study, researchers followed 1,269 adults with an average age of 47 and no diagnosis of cardiovascular disease for about 14 years. For the purposes of the study, late-onset asthma was diagnosed as starting at age 18, with the average diagnosis of participants coming around age 39.5. A control group of early-onset patients had an average age of diagnosis of 8.9 years old.
At the beginning of the study, 111 participants had late-onset asthma and 55 had early-onset asthma, with researchers tracking cardiovascular events including heart attack, stroke, heart failure, angina, cardiac revascularization and cardiac death. The researchers also accounted for other heart disease risk factors such as smoking, high blood pressure, high BMI and diabetes.
Overall, late-onset asthmatic patients were found to be 57 percent more likely to have a cardiovascular health event than those without the condition. Women and people with higher BMI were also found to be more likely to have a heart health event. Early-onset asthma patients, however, had no significant difference in cardiovascular disease health events when compared to those without asthma.
"From a clinical perspective, late onset asthma has two significant implications," Tattersall said. "[One is] people who are at intense cardiovascular risk and need to be monitored. The other is [because of] the similarity with asthma and cardiovascular disease. If somebody comes in with breathing problems or chest pain, knowing the higher risk means these things should be checked out."