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 Alzheimer’s 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. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement Alzheimer's Disease Neuroimaging Initiative; This research was supported by a grant from the Canadian Institutes of Health Research. Financial Disclosures Dr. Morrison is supported by a postdoctoral fellowship from Canadian Institutes of Health Research, Funding Reference Number: MFE-176608. Dr. Dadar reports receiving research funding from the Healthy Brains for Healthy Lives (HBHL), Alzheimer Society Research Program (ASRP), and Douglas Research Centre (DRC). Dr. Collins reports receiving research funding from Canadian Institutes of Health research, the Canadian National Science and Engineering Research Council, Brain Canada, the Weston Foundation, and the Famille Louise & Andre Charron. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The data were obtained from the ADNI database after a written request and application requesting the data was completed. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes ALL data produced in this manuscript are available online at http://www.adni-info.org/