The Link Between Asthma & Heart Disease
Doctors have observed a link between asthma and an increase risk of heart disease but, as with many medical findings, the reasons for the connection aren’t clear.
“No one knows what the link is between heart disease and asthma, but it is a statistical fact,” says Russell B. Leftwich, MD, a physician specializing in allergy and immunology in Nashville, Tenn., and a spokesperson for the American Academy of Allergy Asthma and Immunology. “Even when you take away smoking and other risk factors, there is still an increased risk of heart disease in people with asthma.”
Doctors have a variety of theories about the possible link between asthma and heart disease including:
• Genes. One theory suggests some kind of genetic link. “There are 29 genes known to be associated with asthma,” says Leftwich. “Perhaps it’s one of those genes.”
• Inflammation. A possible link between asthma and heart disease could involve their connection to inflammation. Heart disease is an inflammatory disease: Inflammation makes the arteries harden. As for asthma, it’s caused by airway inflammation. “Inflammation in one part of the body promotes inflammation in other parts of the body,” says Leftwich. “When you have inflammation in one part, you have chemicals released, and those chemicals travel to other parts of the body and cause inflammation at those other sites.”
• Weight. Obesity may be another factor linking asthma and heart disease. It certainly contributes to developing asthma and to developing heart disease, says Leftwich, though what exactly the connection is, is not yet clearly understood.
• Confusing Symptoms. “People who are having heart failure or angina or heart pain such as tightness in the chest may mistake those symptoms for breathing difficulty or other symptoms of asthma,” says Leftwich. Heart failure can cause fluid to build up in the lungs and airways, and can lead to symptoms that resemble asthma symptoms such as wheezing, coughing, and shortness of breath.
Is Asthma Medication a Culprit?
A big question mark about the link between asthma and heart disease also concerns certain asthma medications.
“The medicines used to treat asthma may increase the likelihood of heart events,” says Leftwich. “For example, beta-agonists, which are quick-release drugs, stimulate the heart. It has long been thought that they may increase the chance of a cardiac event.”
Beta-agonists are all adrenalin derivatives and are known to affect the heart, explains Leftwich, adding, “They also lower the potassium level in the blood, which can lead to disturbances in heart rhythm and are also more likely to be used more frequently used in severe asthma attacks.”
Similarly, high doses of corticosteroids, which are also commonly used to treat asthma, have been associated with atrial fibrillation, a condition in which the upper chambers of the heart quiver instead of beating normally.
It’s a chicken-or-egg conundrum: Doctors aren’t sure if the medications are causing the cardiovascular events or whether the asthma attacks are precipitating the heart disease. “Beta-agonists have long been suspected as a cause, but this has not been absolutely confirmed and there are some studies that suggest this is not the link,” says Leftwich.
Asthma and Heart Disease: Other Findings
One recent large-scale study of more than 15,000 men and women found a correlation between adult onset of asthma and heart disease in women. Researchers compared the risk of coronary heart disease or stroke in people with childhood-onset asthma to those with adult-onset asthma. They found that women with adult-onset asthma have twice the risk for coronary heart disease and stroke, even after adjusting data for known heart disease risk factors such as age, body mass index, cigarette use, and a lack of exercise.
As an example of how asthma triggers may be part of the equation, another study found that ordinary exposure to even small amounts of coarse particles in the air, such as road or construction dust, raised bad cholesterol levels and increased coronary risk factors for heart problems in people with asthma. Considering the connection between these two conditions, talk to your doctor about managing asthma symptoms, along with ways to maintain or even boost your cardiovascular health.