Race and Regional Differences in Cerebral Microbleeds in Individuals with Incident Stroke or Transient Ischemic Attack: The REGARDS Study

Background: Cerebral microbleeds (CMBs) are associated with risk of stroke, cognitive impairment, and dementia. The influence of race and/or region of residence on CMB is underexplored. Methods: REasons for Geographic and Racial Differences in Stroke (REGARDS) study participants with incident stroke/TIA and available MRI were included. CMBs were classified as any, non-lobar, lobar or mixed CMB. Counts were recorded. Multivariable logistic regression assessed associations between race and/or region of residence with CMB presence. Multivariable negative binomial regression related these factors to CMB counts. Models adjusted for age, sex, vascular risk factors. Results: Among 808 participants (317 Black participants, 412 in stroke belt), Black participants had higher odds of any CMB, odds ratio (OR) = 1.72; 95% confidence interval (CI) 1.22, 2.43). Stroke belt residents had lower odds of any (OR = 0.51, 95% CI 0.37, 0.72), non-lobar (OR = 0.46; 95% CI 0.24, 0.85), lobar (OR = 0.60; 95% CI 0.38, 0.93) CMBs and lower odds of CMB counts (rate ratio [RR] = 0.66, 95% CI 0.43, 0.99). Black participants residing in the stroke belt had higher odds of any (OR = 1.88; 95% CI 1.11, 3.20) and mixed (OR = 2.99; 95% CI 1.19, 7.74) CMBs. Conclusion: Black participants had higher risk for CMBs. Higher risk in Black participants may suggest increased subclinical vascular brain injury.