Long‐Term Glycemic Exposure, Control Status and Cognitive Function in Older Adults: A Longitudinal Study

AIMS: To evaluate the impact of long-term glycemic exposure and control status on cognitive function in older adults. MATERIALS AND METHODS: Using repeated measurements of fasting blood glucose (FBG) from the Prediction for Atherosclerotic Cardiovascular Disease Risk in China project, we calculated 10-year time-weighted cumulative fasting blood glucose (cumFBG) and glycemic variability, and identified FBG trajectories using group-based trajectory modelling among 26 108 participants. In addition, diabetic patients were categorized as consistently controlled or not according to long-term FBG levels. Mini-Mental State Examination was used to evaluate global and domain-specific cognition, and cognitive impairment was defined according to education-specific cutoffs. Linear and logistic regression models were applied to assess associations between FBG-related indicators and cognition. RESULTS: < 0.05). Compared with participants with cumFBG < 900 mg/dL × year, those with cumFBG ≥ 1260 mg/dL × year had a 0.091-point lower z-standardized global cognitive score (95% CI: -0.142, -0.040) and a 3% increased cognitive impairment risk (OR: 1.030; 95% CI: 1.010, 1.050). Among specific domains, attention appeared more susceptible, with declines emerging when cumFBG ≥ 900 mg/dL × year. Notably, among individuals with cumFBG ≥ 1260 mg/dL × year, increasing trajectory had a 21.2% increased cognitive impairment risk (OR: 1.212; 95% CI: 1.122, 1.310). Higher variability was associated with worse cognition. Furthermore, only diabetic participants with consistent control exhibited cognition comparable to those without diabetes. CONCLUSION: Elevated cumFBG, especially in an increasing pattern, influenced cognition in older adults and sustained glycemic control appeared to mitigate these adverse impacts.