July 8, 2009 -- A new study shows that severe chronic obstructive pulmonary disease (COPD) is associated with greater cognitive impairment in older adults.
Previous research has already linked COPD with impaired cognitive function, or impaired mental skills, but researchers say this is the first study to show the negative impact of COPD on mental performance over time.
"Our findings should raise awareness that adults with severe COPD are at greater risk for developing cognitive impairment, which may make managing their COPD more challenging, and will likely further worsen their general health and quality of life," William W. Hung, MD, MPH, assistant professor at Mount Sinai School of Medicine, says in a news release.
COPD is a progressive disease that affects the lungs and makes it difficult to breathe. The prevalence of the disease increases with age, and it affects nearly 14% of adults over age 75 in the U.S. Emphysema and chronic bronchitis are COPD conditions.
COPD Tied to Cognitive Impairment
In the study, researchers compared mental performance in more than 4,150 adults over age 50 with and without COPD who were tested at least twice between 1996 and 2002.
The results, published in the American Journal of Respiratory and Critical Care Medicine, showed that older adults with severe COPD showed signs of significantly more cognitive impairment than those without the condition, even after adjusting for other illnesses and education level. People with severe COPD reported that their COPD affected daily activities and that they required supplemental oxygen.
After controlling for other factors that may affect cognitive impairment, the average cognitive scores of those with severe COPD were significantly lower than those without the disease by an average of about one point on a 35-point scale.
Although a one-point decrease may seem small, Hung says the level of cognitive impairment associated with COPD in the study would affect many daily tasks, such as handling money and medications. Based on prior studies, that level of decline in cognitive function would likely be associated with a 22% increase in the average number of difficulties people with severe COPD would experience in performing daily tasks.
"While this number may not appear to be of major concern on the individual level, on a population level, it is roughly equivalent to nearly a quarter of severe COPD patients experiencing difficulty with a basic life skill," Hung says.