Diabetes + Depression = Increased Risk of Dementia

People with depression or those with diabetes are more likely than others to develop dementia.  However, although both conditions are treatable, it would be interesting to know how great the risk is for people with both of them.  This question has been tackled by researchers at the University of Washington, Seattle, and the results reported in the Journal of General Internal Medicine.  

Over 3,800 primary care diabetic patients were enrolled; their average age was 63 years.  Depression was determined using the Patient Health Questionnaire, and dementia was diagnosed using International Classification of Disease criteria.  Those with no diagnosis of dementia at baseline were followed for 5 years.

During follow-up there were 199 cases of dementia – 5.2% of the participants.  In the 455 patients with depression, the frequency of dementia was 7.9%, whereas for those without depression, it was 4.8%.  After the necessary adjustments for differences in gender, age, race, education, and health status, those with both diabetes and depression were 2.7-times more likely to develop dementia than those with diabetes but no depression.        

These results show that it’s important to screen for depression in diabetics, and for diabetes in people with depression.  And we should expect studies designed to show if there’s a beneficial effect of treating either condition on the occurrence of dementia.