A recent study reveals that type 2 diabetes may contribute to faster thinning of the brain’s cortex in older adults without cognitive impairment, raising concerns about its broader neurological impacts beyond traditional health risks.
Type 2 diabetes may be doing more than raising the risk of heart, kidney and eye disease. A study published online on 24 August 2026 in Brain found that the condition was linked with faster thinning of the brain’s cortex in several regions of older adults who otherwise showed no cognitive impairment, even after accounting for Alzheimer’s disease markers and cerebrovascular damage.
The research, led by Amaryllis A. Tsiknia at the University of Southern California, followed 1,298 adults in the Health and Aging Brain Study-Health Disparities cohort for almost three years. Among them, 305 had type 2 diabetes. The team compared changes in cortical thickness across 34 brain regions and found quicker thinning in seven areas tied to frontal, parietal and occipital function, including regions involved in movement, spatial processing and visual interpretation.
The association held after statistical adjustment for socioeconomic factors, diabetes-related illnesses, amyloid and tau burden, white matter hyperintensities and APOE ε4 status, a genetic risk factor for Alzheimer’s. Higher baseline HbA1c, a measure of long-term blood sugar control, was also tied to faster thinning in the same regions except the lingual gyrus. The authors said the pattern partly explained the faster decline in processing speed seen in people with diabetes.
The findings fit with earlier research suggesting that elevated glucose and longer diabetes duration can be linked to reduced brain volume or thinner cortex, and that tighter glucose control may slow some of that loss. Still, the new study has limits, including a relatively short follow-up, a small number of MRI scans per participant and a narrow set of cognitive tests. The authors said the brain regions they identified could become useful imaging targets, but only if the results are confirmed in other cohorts.
Disclaimer: This content is for informational purposes only and is not intended to be a substitute for professional medical judgment, advice, diagnosis, or treatment.
