Abstract

Objective To test the hypothesis that type 2 diabetes mellitus is associated with greater decline in cognitive function in middle-aged individuals.

Research design and methods In the Dutch prospective Doetinchem Cohort Study, cognitive functioning was measured twice within a five year time interval in 2613 men and women. Participants were aged 43-70 years at baseline (1995-2002), and no one had a history of stroke. Change in scores on global cognitive function as well as on specific cognitive function domains (memory, speed of cognitive processes, and cognitive flexibility) were compared for respondents with and without type 2 diabetes (verified by the GP, or random plasma glucose levels ≥11.1 mmol/l).

Results At 5-year follow-up, the decline in global cognitive function in diabetes patients was 2.6 times greater than in persons without diabetes. For persons aged 60 years or older, both incident and prevalent diabetes patients showed a 2.5 respectively 3.6 times greater decline in cognitive flexibility than persons without diabetes. For most cognitive domains, the magnitude of cognitive decline in incident diabetes patients was intermediate between that of persons without diabetes and that of patients with diabetes at baseline.

Conclusions Middle-aged persons with type 2 diabetes showed a greater decline in cognitive function than middle-aged persons without diabetes.