Type 2 Diabetes and Diabetic Retinopathy Linked to Higher Dementia Risk: New Study Reveals
USA: A large study published in the American Journal of Ophthalmology has revealed that individuals with type 2 diabetes have a higher risk of Alzheimer’s disease and dementia compared with those without diabetes. Importantly, greater severity of diabetic retinopathy was associated with an increased risk of vascular and all-cause dementia, but not specifically Alzheimer’s disease.
The analysis included 769,930 adults aged 65 years and older from the TriNetX Global Collaborative Network. Individuals with a dementia diagnosis before diabetes and those with macular edema were excluded, strengthening the temporal link between diabetes-related eye disease and later dementia risk.
The study, led by Millen S. Khangura from the Renaissance School of Medicine at Stony Brook University, aimed to clarify whether the severity of diabetic retinopathy (DR) influences the likelihood of developing dementia. Diabetes mellitus and its microvascular complications have previously been linked to cognitive decline, but the relationship between varying stages of DR and different dementia subtypes has remained unclear.
In the retrospective cohort study, participants were categorized into four groups: proliferative diabetic retinopathy (PDR), nonproliferative diabetic retinopathy (NPDR), type 2 diabetes without retinopathy, and individuals without diabetes. To ensure balanced comparisons, groups were propensity score-matched for demographic and clinical variables. The primary outcomes included new diagnoses of all-cause dementia, Alzheimer’s disease (AD), and vascular dementia (VD), analyzed using Cox proportional hazards models and Kaplan-Meier survival curves.
The study revealed the following findings:
- The study identified 14,034 individuals with proliferative diabetic retinopathy (PDR), 29,188 with nonproliferative diabetic retinopathy (NPDR), 208,640 with type 2 diabetes without retinopathy, and 447,054 without diabetes.
- Compared with nondiabetic individuals, all diabetic groups (PDR, NPDR, and diabetes without retinopathy) showed a significantly increased risk of all-cause dementia, Alzheimer’s disease (AD), and vascular dementia (VD).
- The greatest risks were observed among individuals with proliferative diabetic retinopathy.
- Participants with PDR had a 58% higher risk of all-cause dementia and more than a twofold increased risk of vascular dementia compared with those without diabetes.
- Compared with individuals who had diabetes without retinopathy, both PDR and NPDR were associated with a significantly higher risk of all-cause dementia and vascular dementia.
- No significant increase in Alzheimer’s disease risk was found when comparing retinopathy groups (PDR or NPDR) with diabetes patients without retinopathy.
- Further analysis showed that PDR was associated with a higher risk of all-cause dementia and vascular dementia than NPDR, indicating a severity-dependent association.
The findings suggest that worsening diabetic retinopathy may reflect broader systemic microvascular damage that parallels small vessel disease in the brain, contributing particularly to vascular dementia. In contrast, Alzheimer’s disease risk appeared elevated primarily when diabetic individuals were compared with those without diabetes.
The authors noted that routine ophthalmologic evaluations in older adults with diabetes could provide more than visual health benefits. Detection of progressive retinal disease may help identify patients at increased risk of cognitive decline, offering an opportunity for earlier monitoring and intervention strategies aimed at preserving brain health.
Reference:
Khangura MS, Spratt MA, Gao A, Manhapra A, Siegel NH, Chen X, Poulaki V, Ness S, Stein T, Subramanian ML. The Association Between Diabetic Retinopathy Severity and Dementia Risk: A TriNetX Longitudinal Cohort Study. Am J Ophthalmol. 2026 Feb 13:S0002-9394(26)00073-5. doi: 10.1016/j.ajo.2026.02.014. Epub ahead of print. PMID: 41692179.
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