A study on a group of Medicare recipients aged 65 years and older has revealed a link between prevalent mild cognitive impairment and an increased risk of dementia.
Depressive symptoms occur in 3 percent to 63 percent of patients with mild cognitive impairment (MCI) and some studies have shown an increased dementia risk in individuals with a history of depression. The mechanisms behind the association between depression and cognitive decline have not been made clear and different mechanisms have been proposed, the researchers pointed out.
Edo Richard, M.D., Ph.D., of the University of Amsterdam, the Netherlands, and colleagues evaluated the association of late-life depression with MCI and dementia in a group of 2,160 community-dwelling Medicare recipients.
"We found that depression was related to a higher risk of prevalent MCI and dementia, incident dementia, and progression from prevalent MCI to dementia, but not to incident MCI," the researchers noted.
Baseline depression was associated with prevalent MCI (odds ratio [OR], 1.4) and dementia (OR, 2.2), while baseline depression was associated with an increased risk of incident dementia (hazard ratio [HR], 1.7) but not with incident MCI (HR, 0.9).
Patients with MCI and coexisting depression at baseline also had a higher risk of progression to dementia (HR, 2.0), especially vascular dementia (HR, 4.3), but not Alzheimer disease (HR, 1.9), according to the study results.
"Our finding that depression was associated cross sectionally with both MCI and dementia and longitudinally only with dementia suggests that depression develops with the transition from normal cognition to dementia," the researcher added.
The results were published Online First by Archives of Neurology, a JAMA Network publication.