Previous studies suggest cross-sectional associations between a diagnosis of chronic obstructive pulmonary disease (COPD) and mild cognitive impairment (MCI). However, few studies have assessed whether COPD, a potentially modifiable factor, is associated with an increased risk of MCI and if the relation is specific to type of MCI.
To investigate whether a diagnosis of COPD, and COPD duration, is associated with an increased risk of incident MCI, and MCI subtypes (amnestic MCI (a-MCI) and non-amnestic MCI (na-MCI)).
Mayo Clinic Study on Aging, a prospective population-based cohort study.
Olmsted County, Minnesota.
The study included 1425 cognitively normal individuals aged 70–89 years, who were randomly selected from Olmsted County, MN, on October 1, 2004, using the medical records linkage system.
At baseline and every 15 months thereafter, participants were assessed with a nurse interview, neurological examination, and neuropsychological testing. A diagnosis of COPD was confirmed via medical record chart review. A baseline diagnosis of COPD and disease duration were examined as risk factors for MCI and MCI-subtypes using Cox proportional hazards models and adjusting for demographic variables and medical comorbidities, using age as the time scale.
MAIN OUTCOME MEASURES
Incident MCI, amnestic MCI, non-amnestic MCI
Of 1425 cognitively normal subjects at baseline, 370 developed incident MCI. The median duration of follow-up was 5.1 years (Interquartile Range [IQR], 3.8–5.4 years). COPD significantly increased the risk of na-MCI by 83% (HR 1.83; 95% CI, 1.04–3.23), but not any MCI or a-MCI in multivariate analyses. There was a dose-response relationship such that individuals with COPD duration of 5 years or longer at baseline had the greatest risk of both MCI (HR 1.58, 95% CI:1.04, 2.40) and na-MCI (HR 2.58, 95% CI:1.32–5.06).
CONCLUSIONS AND RELEVANCE
COPD was associated with an increased risk of MCI, particularly na-MCI. There was a dose-response relationship between COPD duration and risk of MCI. These findings highlight the importance of COPD as a risk factor for MCI and may provide a substrate for early intervention to prevent or delay the onset and progression of MCI, particularly na-MCI.