Albuminuria, cognition, and MRI biomarkers of cerebrovascular disease in American Indians of the Zuni Pueblo.

Background: Elevated urine albumin to creatinine ratio (UACR) is associated with cerebrovascular disease and cognitive impairment in older adults, though few studies have evaluated these relationships in midlife. This is particularly important to assess in American Indian populations, which are disproportionately impacted by diabetes and kidney disease. Additionally, evidence suggests that biomarkers may perform differently in underrepresented groups, thus, it is crucial to validate biomarkers in this unique population. Methods: Twenty-five participants from the Zuni Pueblo underwent neuropsychological assessment and an MRI that included fluid attenuated inversion recovery (FLAIR) and diffusion imaging to calculate recently developed MRI markers of cerebrovascular small vessel disease (Peak width of Skeletonized Mean Diffusivity (PSMD), mean free-water fraction (mFW), white matter hyperintensity (WMH)). Results: Regression analyses indicated no significant associations between UACR, MRI biomarkers and cognitive outcomes. Analyses of covariance indicated that the Zuni Indian cohort exhibited reduced white matter damage relative to an existing cohort of older adults with vascular cognitive impairment when accounting for age, sex, and education. Slower processing speed was associated with greater white matter disease across all measures examined. Conclusions: Our pilot study validated the use of MRI biomarkers of cerebrovascular disease in this unique cohort of American Indians.