Clinical Geriatrics

Among well-functioning older adults, diabetes mellitus (DM) and poor glucose control among those with DM are associated with worse cognitive function and greater cognitive decline, a new study published in the Archives of Neurology found. Kristine Yaffe, MD, professor of psychiatry, neurology, and epidemiology, University of California San Francisco, and colleagues conducted a prospective cohort study at two community clinics with a total of 3069 participants (mean age, 74.2 years; 42% black; 52% women). The study participants completed the Modified Mini-Mental State Examination (3MS) and Digit Symbol Substitution Test (DSST) at baseline and at select intervals over a period of 10 years. Glycosylated hemoglobin A1C levels were determined at baseline, at 4 years, 6 years, and 10 years. The study found that at baseline, 23.4% of participants (n=717) had prevalent DM; the remaining 76.6% (n=2352) were without DM, 159 of which had developed incident DM during follow-up.

Participants with DM had lower baseline test scores than participants without DM.  This finding reached statistical significance (P=.001). Results from mixed-effects models showed a similar pattern for 9-year decline scores between the other two groups, but were not statistically different from the group without DM. Among participants with prevalent DM, glycosylated hemoglobin A1C level was associated with lower average mean cognitive scores.

“This [study] suggests that severity of DM may contribute to accelerated cognitive aging,” the authors wrote in the study.