Key result
Higher HbA1c shows no independent link to mild cognitive impairment after full covariate adjustment.
Why the study?
T2D is a risk factor for cognitive impairment, but the role of glycemia changes over time in cognitive impairment risk remains unclear.
Does HbA1c trajectory over 20 years increase the risk of cognitive impairment in adults with prediabetes or T2D?
Cohort (n=1,682)
Does HbA1c trajectory over 20 years increase the risk of cognitive impairment in adults with prediabetes or T2D?
Long-term glycemia trajectories in prediabetes and T2D do not independently confer risk for cognitive impairment when accounting for established demographic, genetic, and cardiovascular risk factors.
Answers are grounded in this paper and cite their sources.
Mean HbA1c does not independently predict aMCI after full adjustment; leaves open glycemic effects on cognition in prediabetes.
Introduction and Objective: T2D is a risk factor for CI. However, the role of glycemia changes over time in CI risk remains unclear. We investigated longitudinal glycemia trajectories in relation to CI among people living with pre-diabetes or T2D in DPPOS. Methods: Among 1,682 middle-aged adults with pre-diabetes at enrollment (median [IQR]; age 49 [43,53]) we investigated the association of HbA1c trajectory over 20 years of follow-up with prevalent CI assessed via the National Alzheimer’s Coordinating Center Uniform Data Set (v3) 25 years after enrollment. HbA1c trajectories were characterized from a random effects model as intercept (mean HbA1c over time) and slope (rate of HbA1c change over time). CI categories were dementia (n=48), amnestic mild cognitive impairment (aMCI; n=137), non-amnestic MCI (naMCI; n=136), CI-not-MCI (n=189), and no CI (reference; n=973). Multinomial logistic models sequentially added a priori covariates for demographics (DPP randomization group, age, sex, education, income, race and ethnicity), cardiovascular risk factors (smoking status, HDL, LDL, systolic blood pressure[SBP]), and APOE genotype. Results: Independent of demographics, higher mean HbA1c was associated with higher risk for aMCI (OR=1.77 [95% CL: 1.06, 2.97; p=0.03]). However, in sequentially adjusted models, HbA1c parameters were not associated with risk for CI. In the fully adjusted model, older age, male sex, Black race and Hispanic ethnicity, higher SBP, and APOE copy number were associated with higher risk for CI (p<0.05, for all). Conclusion: In the context of pre-diabetes and T2D, glycemia trajectory may not confer risk for CI that is independent of established demographic, genetic, and cardiovascular risk factors. The findings emphasize the importance of managing of multi-faceted cardiometabolic risks for CI and understanding high-CI-risk groups in the setting of pre-diabetes and T2D. Disclosure A. Shapiro: None. R. Shu: None. M. Temprosa: None. D. Dabelea: None. S. Kahn: Advisory Panel; Current; AltPep, Amgen Inc., Congruence Therapeutics, Eli Lilly and Company, General Medicines, Kayothera, Merck & Co., Inc., Neurimmune, Novo Nordisk, Roche Pharmaceuticals. V. Shah: None. W. Knowler: None. B. Laferrère: Consultant; Ended; Azurity. J.A. Luchsinger: Consultant; Current; Merck KGaA, Novo Nordisk. Other - Merck KGaA provides investigational product including matching placebo free of charge for an NIH funded clinical trial.; Current; Merck KGaA. S. Aleksic: Stock/Shareholder; Current; Novo Nordisk, Lilly. S. Kuo: None. W. Hsueh: None. O. Carmichael: Research Support; Current; Eli Lilly and Company. D. Research Group: None.
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Shapiro et al. (2026) conducted a cohort in Pre-diabetes or Type 2 Diabetes (n=1,682). Higher mean HbA1c (glycemia trajectory) vs. Lower mean HbA1c was evaluated on Prevalent cognitive impairment (CI) assessed 25 years after enrollment (OR 1.77, 95% CI 1.06-2.97, p=0.03). Higher mean HbA1c was associated with a higher risk for amnestic mild cognitive impairment independent of demographics, but not after full covariate adjustment.
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