Researchers from the Mayo Clinic in Jacksonville, Florida said the findings suggested earlier intervention and treatment of COPD may help delay or even prevent the onset of dementia.
Their study found that a diagnosis of COPD in patients aged 70-89 was linked to a 83% increased risk of developing non-amnestic MCI, which affects thinking skills other than memory, within five years.
This risk rose to 158% higher in patients who had COPD for over five years, suggesting a dose-response relationship. Risk of any type of MCI, including that which affects memory, was 58% higher.
Previous studies have linked COPD with poor performance in attention, memory and brain function, but this was the first study to investigate an association between COPD and overall cognitive decline.
Patients with COPD tend to have increased levels of inflammatory markers and an elevated risk of developing cardiovascular disease. Both of these conditions have been identified as playing a role in the development of MCI, but the study showed COPD was also an independent predictor of the condition.
Another possible explanation could be increased levels of hypoxia in the brains of COPD patients, which can lead to inflammation and neuron damage, researchers said.
Study authors concluded: 'Our 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.'
The study was published in JAMA Neurology.