Impact of Microvascular Complication Burden on the Risk of Dementia and Cognitive Decline in Patients With Diabetes: A Systematic Review of Latest Evidence

Diabetes mellitus is an established risk factor for dementia; however, the specific contributions of microvascular complications and glycemic control to cognitive decline remain unclear. This systematic review synthesizes current evidence on the association between microvascular complication burden and dementia risk in individuals with diabetes. A comprehensive search of PubMed, the Cochrane Library, and Embase was conducted for studies published through March 2026, including cohort and cross-sectional studies evaluating microvascular complications or glycemic control in relation to dementia or cognitive decline. The Newcastle-Ottawa Scale was used to evaluate the quality of the study. A total of 1,697,156 participants from five studies, two cross-sectional and three cohort, were included. Cohort studies consistently showed that microvascular problems are linked to a higher incidence of dementia; the largest relationships were found with diabetic neuropathy (hazard ratio (HR) 1.12-1.26) and nephropathy (HR 1.13-1.23), but results for retinopathy were inconsistent. Furthermore, an 8% increased risk of dementia was associated with every 1% increase in HbA1c, and cognitive decline was independently influenced by HbA1c variability. Additionally, significant associations were found between the severity of microvascular problems and HbA1c levels (r = 0.839-0.870). In individuals with diabetes, microvascular complications-especially neuropathy and nephropathy-are generally linked to a higher risk of dementia, and poor glycemic management seems to worsen both microvascular damage and cognitive decline. These results emphasize the importance of optimizing glycemic management and routine screening for microvascular complications as viable methods to maintain cognitive health.