Cardiovascular risk factors, white matter hyperintensities and executive function: Difference among Mexican Americans and non‐Hispanic whites

Background Cardiovascular risk factors (CVRF) differ between ethnicities but is not clear if the relationship with white matter hyperintensities (WMH) and executive function is also different. The purpose of this study was to examine the prevalence of cardiovascular risk factors and their effect on WMH and executive function in a sample of Non‐Hispanic Whites (NHW) and Mexican American (MA) elders. Method We studied 1100 (585 NHW, 515 MA) cognitively normal subjects from the Health and Aging Brain Study (HABS‐HD) with signed consent, 3T MRI (Siemens Skyra), clinical evaluation, and cognitive testing. WMH volume was measured from FLAIR using the Statistical Parametric Mapping (SPM) Lesion Segmentation Tool. Linear regression was used to predict the effect of CVRF on WMH. Log transformed WMH adjusted for intracranial volume (derived from Freesurferv6.0 analysis of T1 MPRAGE) were used to predict Trails B (executive function). Age, sex, and education were entered as covariates in the models. Result Sixty‐three percent of the sample were female. MA were significantly younger (mean age 62.6 vs 68.8), less educated (mean education years 9.84 vs 15.64), and had smaller WMH volumes (‐0.13 vs 0.02) than NHW. There was no difference on Trails B scores. MA had a higher prevalence of diabetes and obesity (p=<0.0001), but the prevalence of hypertension and dyslipidemia did not differ among the groups. WMH volume was associated with hypertension in both groups (p=<0.001), while the association with diabetes was only present on MA (p=<0.001). Dyslipidemia and obesity were not associated with WMH volume in any group. WMH predicted Trails B scores in NHW (B = ‐0.13, t =‐4.29, p = <0.001), and MA (B = ‐0.17, t = ‐3.25, p = 0.001). Results remained significant after adjusting for age, sex, education, and CVRF. Conclusion Our findings suggest that the association of CVRF with WMH differs among MA and NHW. Executive function was related to WMH volume in both groups, but it is likely that for MA a metabolic component is more important. Ethnicity should be considered when assessing the association of CVRF, small vessel disease, and cognition.