Optimized glucose control poses increased dementia risk in elderly diabetics

Large decreases in glycaemic level potentially represent a red flag for dementia in older adults with type 2 diabetes (T2D), suggesting that optimizing glycaemic level in later life requires caution, according to a recent study.

Researchers followed 2,246 community-living dementia-free Chinese older adults with T2D for 6 years to explore whether achieving the glycaemic goal recommended by the American Diabetes Association (ADA) within a year (HbA1c <7.5 percent) was associated with lower risk of dementia.

Over a median follow-up of 5 years, 297 (13.2 percent) participants died and 242 (10.8 percent) developed dementia. Participants with dementia were mostly female and older, with lower educational attainment, more physical comorbidities, and less healthy lifestyle practices.

Significantly more participants in the dementia than in the cognitively stable group had HbA1c ≥7.5 percent at baseline but <7.5 percent by year 1 (8.3 percent vs 5.8 percent; p=0.14). Logistic regression analysis confirmed the association between incident dementia and achieving the ADA-recommended glycaemic goal at 1 year (odds ratio [OR], 1.92, 95 percent confidence interval [CI], 1.05–3.52; p=0.03). This association remained despite adjusting for glycaemic variability, severe hypoglycaemic episodes, physical, psychosocial and lifestyle factors (p<0.05).

In sensitivity analyses, a relative HbA1c reduction of ≥10 percent within a year was associated with higher dementia risk in those with high (≥8 percent) and moderate (6.5–7.9 percent) HbA1c at baseline.

The findings highlight the need for careful control of HbA1c levels, according to the researchers, stressing that treatment in this population should focus on not only achieving a particular glycaemic target but also promoting moderation of glycaemic level.