Diabetic Peripheral Neuropathy May Be an Independent Risk Marker for Dementia and Cerebrovascular Disease

AIMS: Diabetic peripheral neuropathy (DPN) may be linked to central nervous system changes. This study examined if DPN is associated with an increased risk of incident dementia and cerebrovascular disease in individuals with Type 1 (T1D) and Type 2 diabetes (T2D). MATERIALS AND METHODS: This register-based cohort study (1998-2020) used data from Steno Diabetes Center Copenhagen and Danish National Health Registries. Individuals without prior dementia or cerebrovascular disease and available vibration perception threshold (VPT) measurements were included. DPN was defined using two approaches: a fixed threshold (VPT > 25 V) and an age-sex-height-adjusted threshold. Outcomes were identified using ICD-10 and procedure codes. Incidence rate ratios (IRRs) for individuals with versus without DPN were estimated using Poisson regression, stratified by diabetes type and modelled for both DPN definitions. RESULTS: Among 5641 individuals with T1D (mean age 40.5 years (SD 15.8), 45.3% female), DPN (VPT > 25 V) was associated with increased rates of cerebrovascular disease (IRR 1.45, 95% CI 1.11-1.91) but not dementia (IRR 1.61, 95% CI 0.75-3.48). In 9395 individuals with T2D (mean age 59.9 years (SD 13.0), 38.6% female), DPN (VPT > 25 V) was associated with increased rates of both dementia (IRR 4.36, 95% CI 2.07-9.16) and cerebrovascular disease (IRR 1.45, 95% CI 1.18-1.80). Results were similar using the adjusted threshold. Additional adjustment for retinopathy and nephropathy only attenuated the IRR for cerebrovascular disease in T1D (IRR 1.18, 95% CI 0.87-1.60); findings in T2D were unchanged. CONCLUSIONS: DPN was an independent risk marker for dementia in T2D and cerebrovascular disease in both T1D and T2D, highlighting its potential role in identifying at-risk individuals.