White matter hyperintensity and cognitive functioning in the racial and ethnic minority cohort of the Framingham Heart Study.

BACKGROUND: Previous studies have demonstrated an association between white matter hyperintensities (WMH) and cognitive performance primarily in Caucasian samples, limiting generalizability to other ethnic and racial groups. This study investigated the association of WMH and cognition in an ethnic and racial minority cohort (Omni) of the Framingham Heart Study and compared these results to the Caucasian (Offspring) cohort.

METHODS: Quantitative brain MRI and neuropsychological evaluations were performed on stroke- and dementia-free participants. Cognitive assessment included verbal memory, visuospatial memory and organization, language, and executive functioning. Linear regression models were conducted to assess the association between WMH and cognitive function.

RESULTS: The Omni group presented with demographic factors that significantly differed from those of the Offspring group: they were younger, but had more stroke risk factors such as hypertension. In the Offspring group, WMH volume was significantly associated with poorer performance on tests of executive function and visual organization. No significant associations between WMH and cognitive measures were found in the Omni group, but no differences (significant interaction terms) were seen between the regression coefficients.

CONCLUSIONS: The Omni cohort had greater variability in factors that may mediate the association of WMH and cognition. More research is needed to investigate how stroke risk factors impact on the occurrence of WMH and its association with cognition in more diverse cohorts.