Type 2 diabetes is an established risk factor for dementia. However, the roles of glycemic control and diabetic complications in the development of dementia have been less well substantiated. This large-scale cohort study aims to examine associations of longitudinal HbA1c levels and diabetic complications with the risk of dementia incidence among patients with type 2 diabetes.


Data of eligible patients with diabetes, aged ≥50 years in the U.K. Clinical Practice Research Datalink from 1987 to 2018, were analyzed. Time-varying Cox regressions were used to estimate adjusted hazard ratios (HRs) and 95% CIs for dementia risk.


Among 457,902 patients with diabetes, 28,627 (6.3%) incident dementia cases were observed during a median of 6 years’ follow-up. Patients with recorded hypoglycemic events or microvascular complications were at higher risk of dementia incidence compared with those without such complications (HR 1.30 [95% CI 1.22–1.39] and 1.10 [1.06–1.14], respectively). The HbA1c level, modeled as a time-varying exposure, was associated with increased dementia risk (HR 1.08 [95% CI 1.07–1.09] per 1% HbA1c increment) among 372,287 patients with diabetes with postdiagnosis HbA1c records. Similarly, a higher coefficient of variation of HbA1c during the initial 3 years of follow-up was associated with higher subsequent dementia risk (HR 1.03 [95% CI 1.01–1.04] per 1-SD increment).


Higher or unstable HbA1c levels and the presence of diabetic complications in patients with type 2 diabetes are associated with increased dementia risk. Effective management of glycemia might have a significant role in maintaining cognitive health among older adults with diabetes.

This article contains supplementary material online at https://doi.org/10.2337/figshare.14484852.

Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered. More information is available at https://www.diabetesjournals.org/content/license.
You do not currently have access to this content.