Objective: To determine whether chronic kidney disease (CKD) is associated with incident dementia independent of cerebral small-vessel disease (SVD) in patients with vascular risk factors.
Methods: Using data from a Japanese cohort of participants with vascular risk factors in an ongoing observational study from 2001, we evaluated the association between CKD at baseline and incident dementia. Baseline brain MRI was used to determine SVD (lacunar infarction, white matter hyperintensities), medial-temporal atrophy, and subcortical atrophy. Cox proportional hazards analyses were performed for predictors of dementia adjusting for age, sex, APOE ε4 allele, educational level, baseline Mini-Mental State Examination score, cerebrovascular events, vascular risk factors, and MRI findings.
Results: Of the 600 subjects (mean age 68 ± 8.3 years, 57% male, 12.8 ± 2.6 years of education; CKD: 29%), 50 patients with incident dementia (Alzheimer disease: 24; vascular dementia: 18; mixed-type dementia: 5; other types: 3) were diagnosed during the median 7.5-year follow-up. CKD at baseline was associated with an increased risk of all-cause dementia in models adjusted for age, sex, educational level, and APOE ε4 allele. The associations of CKD at baseline remained significant even after additional adjusting for MRI findings and confounding variables (hazard ratio: 1.96 [1.08-3.58], p = 0.026).
Conclusions: CKD is independently related to the risk of all-cause dementia in patients with vascular risk factors. Our results reinforce the hypothesis that CKD exerts deleterious effects on dementia incidence.