A Diabetes Genetic Risk Score Is Associated With All-Cause Dementia and Clinically Diagnosed Vascular Dementia in the Million Veteran Program

• Published in: Diabetes care Vol. 45; no. 11; pp. 2544 - 2552
• Main Authors: Litkowski, Elizabeth M, Logue, Mark W, Zhang, Rui, Charest, Brian R, Lange, Ethan M, Hokanson, John E, Lynch, Julie A, Vujkovic, Marijana, Phillips, Lawrence S, Lange, Leslie A, Hauger, Richard L, Raghavan, Sridharan
• Format: Journal Article
• Language: English
• Published: United States American Diabetes Association 01.11.2022
• Subjects: Alzheimer Disease - complications; Alzheimer's disease; Dementia; Dementia disorders; Dementia, Vascular; Diabetes; Diabetes mellitus; Diabetes mellitus (non-insulin dependent); Diabetes Mellitus, Type 2 - complications; Epidemiology/Health Services Research; Genetic diversity; Genetic variance; Health risks; Humans; Medical diagnosis; Minority & ethnic groups; Neurodegenerative diseases; Pathogenesis; Research design; Risk; Risk Factors; Statistical analysis; Vascular dementia; Veterans
• ISSN: 0149-5992; 1935-5548
• DOI: 10.2337/dc22-0105

Diabetes and dementia are diseases of high health care burden worldwide, and studies have shown that diabetes is associated with an increased relative risk of dementia. We set out to examine whether type 2 diabetes-associated genetic variants were associated with dementia and whether they differed by race/ethnicity or clinical dementia diagnosis. We evaluated associations of two type 2 diabetes genetic risk scores (GRS and GRS-nonAPOE: a score without rs429358, a variant associated with Alzheimer disease [AD]) with three classifications of clinical dementia diagnoses in the Million Veteran Program (MVP): all-cause dementia, vascular dementia (VaD), and AD. We conducted our analysis stratified by European (EUR), African (AFR), and Hispanic (HIS) races/ethnicities. In EUR, we found associations of the GRS with all-cause dementia (odds ratio [OR] 1.06, P = 1.60e-07) and clinically diagnosed VaD (OR 1.12, P = 5.2e-05) but not with clinically diagnosed AD (OR 1.02, P = 0.43). The GRS was not associated with any dementia outcome in AFR or HIS. When testing with GRS-nonAPOE, we found that effect size estimates in EUR increased and P values decreased for all-cause dementia (OR 1.08, P = 2.6e-12), for VaD (OR 1.14, P = 7.2e-07), and for AD (OR 1.06, P = 0.018). For AFR, the association of GRS-nonAPOE and clinically diagnosed VaD (OR 1.15, P = 0.016) was statistically significant. There were no significant findings for HIS. We found evidence suggesting shared genetic pathogenesis of diabetes with all-cause dementia and clinically diagnosed VaD.