Cognitive impairment linked to COPD

Patients with chronic obstructive pulmonary disease (COPD) may be at increased risk of mild cognitive impairment (MIC), a study has suggested (Mayo Clinic Proceedings 2013;88:1222).

COPD was associated with an almost twofold higher odds ratio for MCI, a condition described as an intermediate stage between normal cognitive aging and dementia.

The data come from the population-based Mayo Clinic Study of Ageing which has enrolled nearly 2,000 participants, aged 70 to 89 years. MCI was diagnosed by nurse assessment, neurological evaluation and neuropsychological testing; COPD was identified by review of medical records. Fifteen per cent of participants had COPD, although only 30 per cent of them were receiving regular treatment for the condition.

Compared with those without COPD, patients with COPD had a higher frequency of MCI (27 per cent vs 15 per cent; P<0.001). The odds of having MCI were almost two times higher in patients with COPD than those without (odds ratio 1.87, 95 per cent confidence interval 1.34–2.61), after controlling for cardiovascular comorbidities and other confounding factors. The odds of MCI increased with the duration of COPD.   

The researchers emphasise that no causal association is proved by their data. They say that longitudinal studies are now needed to further examine COPD as a potential risk factor for MCI.