Polygenic risk score and cluster-based analysis suggests links between type 2 diabetes and vascular dementia in the KARE study.

Type 2 diabetes is an established risk factor for dementia. However, how its genetic heterogeneity affects different dementia subtypes remains unclear. In this study, we investigate the associations between genetic risk of type 2 diabetes and dementia subtypes among 33,136 older Chinese adults from the KARE cohort. We find that a higher overall polygenic risk score for type 2 diabetes is significantly associated with an increased risk of vascular dementia, but not Alzheimer's disease. Further analyses using cluster-specific partitioned polygenic score show that elevated genetic risk specific to the hyperinsulinemia pathway is strongly associated with increased incidence of vascular dementia. These findings highlight the potential role of insulin-related metabolic abnormalities in the pathogenesis of vascular dementia and provide genetic evidence to support the use of the hyperinsulinaemia pathway as a clinically relevant marker for early risk stratification and precision prevention strategies.