COPD Linked with Mild Cognitive Impairment

Patients with chronic obstructive pulmonary disease (COPD) are about twice as likely to develop mild cognitive impairment, according to a recent study in the Mayo Clinic Proceedings.

A stage between normal cognitive aging and dementia, mild cognitive impairment increases the likelihood of a patient progressing to dementia and Alzheimer’s disease. Researchers analyzed data from nearly 2,000 patients, ages 70 to 89, in the Mayo Clinic Study on Aging to investigate the association of COPD with mild cognitive impairment in elderly patients.

Of these, 317 had mild cognitive impairment and, overall, about 288 had COPD. Results showed that patients with COPD had a higher prevalence of mild cognitive impairment than those with COPD.

“We also found that patients with longer duration of COPD had higher odds of cognitive impairment,” says study co-author Balwinder Singh, MD, a neurology research collaborator with Mayo Clinic.

The odds ratio for mild cognitive impairment increased from 1.60 in patients with a COPD duration of 5 years or less to 2.10 in patients with a COPD duration of more than 5 years. While the specific reason for this link has not been identified yet, Singh says the association between COPD and mild cognitive impairment risk could potentially be mediated by:

• Hypoxia in COPD, which could lead to impairment in memory and executive tasks requiring attention allocation.

• Altered/depressed cerebral perfusion in COPD, which could have a significant effect on cognitive function.

• The increase in systematic inflammatory mediators with COPD, which previously have been associated with cognitive decline.

“In the absence of any effective therapy for dementia, the identification of risk factors for the development of mild cognitive impairment may hold the best promise for preventing or delaying the progression of early cognitive changes to clinical dementia,” the authors wrote.

Singh hopes that closer monitoring of patients with COPD and other risk factors—including diabetes, cardiac disease, stroke, and age—could lead to early intervention to prevent the incidence or progression of cognitive impairment.

“COPD is a major risk factor for cognitive impairment, and it is imperative to keep a watch on such patients,” he says. He and his colleagues have also completed a prospective study of COPD and cognitive impairment, which is currently under review for publication.

—Colleen Mullarkey

Reference

Singh B, Parsaik AK, Mielke MM, Roberts RO, Scanlon PD, Geda YE, et al. Chronic obstructive pulmonary disease and association with mild cognitive impairment: the Mayo Clinic Study of Aging. Mayo Clin Proc. 2013 Nov;88(11):1222-30.