Racial differences in white matter hyperintensity burden in aging, MCI, and AD

White matter hyperintensities may be one of the earliest pathological changes in aging and may potentially accelerate cognitive decline. Whether race influences WMH burden has been conflicting. The goal of this study was to examine if race differences exist in WMH burden and whether these differences are influenced by vascular factors [i.e., diabetes, hypertension, body mass index (BMI)]. Participants from the Alzheimers Disease Neuroimaging Initiative were included if they had a baseline MRI, diagnosis, and WMH measurements. Ninety-one Black and 1937 White individuals were included. Using bootstrap re-sampling, 91 Whites were randomly sampled and matched to Black participants based on age, sex, education, and diagnosis 1000 times. Linear regression models examined the influence of race on baseline WMHs with and without vascular factors: WMH [~] Race + Age + Sex + Education + BMI + Hypertension + Diabetes and WMH [~] Race + Age + Sex + Education. The 95% confidence limits of the t-statistics distributions for the 1000 samples were examined to determine statistical significance. All vascular risk factors had significantly higher prevalence in Black than White individuals. When not including vascular risk factors, Black individuals had greater WMH volume overall as well as in frontal and parietal regions, compared to White individuals. After controlling for vascular risk factors, no WMH group differences remained significant. These findings suggest that vascular risk factors are a major contributor to racial group differences observed in WMHs.