A common lung condition, COPD (chronic obstructive pulmonary disease) diminishes the heart's ability to pump effectively even when the disease has no or mild symptoms, according to research published in the Jan. 21 issue of the New England Journal of Medicine. The study is the first time researchers have shown strong links between heart function and mild COPD. The research was funded by the National Heart, Lung, and Blood Institute (NHLBI) of the National Institutes of Health.
Researchers have long known that severe cases of COPD have harmful effects on the heart, decreasing its ability to pump blood effectively. The new results suggest that these changes in the heart occur much earlier than previously believed, in mild cases and even before symptoms appear. One in five Americans over the age of 45 has COPD, but as many as half of them may not even be aware of it.
"This study shows that COPD, even in its mildest form, is associated with diminished heart function," said NHLBI Acting Director Susan B. Shurin, M.D. "We now have evidence that the presence of even mild COPD may have important health implications beyond the lungs."
COPD is the fourth leading cause of death in the United States, and it is strongly associated with smoking. COPD often involves destruction of lung tissue, called emphysema, as well as narrowed airways, persistent cough, and mucus production, known as chronic obstructive bronchitis. These abnormalities impair the flow of air in the lungs and make breathing more difficult.
Although damage to the airways from COPD is not fully reversible, treatments can substantially improve a patient's daily life. "COPD is one of the big killers in the United States, yet it is unknown to many," said James P. Kiley, Ph.D., director of the NHLBI Division of Lung Diseases. "Unfortunately, many people with COPD don't recognize common symptoms such as having shortness of breath while doing activities they used to be able to do. It's important that we continue to increase awareness of the signs of COPD and available treatments."
Using breathing tests and imaging studies of the chest, researchers measured heart and lung structure and function in 2,816 generally healthy adults (average age of 61 years). Study participants were part of the MESA Lung Study, an extension of the Multi-Ethnic Study of Atherosclerosis (MESA), a large, NHLBI-supported study focused on finding early signs of heart, lung, and blood diseases before symptoms appear.