Impact of white matter hyperintensity volume on cognition among US Mexican American adults

Abstract

Objective: Higher white matter hyperintensity (WMH) volume is a marker of cardiovascular disease (CVD) risk. CVD risk factors increase risk for Alzheimer's disease and related dementias (ADRD). Mexican Americans (MA) and individuals of other Hispanic/Latino heritages have higher risk for CVD and ADRD. However, knowledge of associations between WMH volume and cognition in these groups remains limited.

Method: We conducted a cross-sectional study of associations between WMH volume and neuropsychological performance (attention/executive functioning, memory) in MA (n = 851) and non-Hispanic White (NHW; n = 747) adults in the Health and Aging Brain Study: Health Disparities.

Results: The MA group (mean age = 63.72 ± 7.90 years; 66.3% female) had higher rates of consensus diagnoses of hypertension and diabetes, whereas the NHW group (mean age = 69.18 ± 8.65 years; 55.2% female) had higher rates of diagnosed CVD (ps < .01). WMH volumes were higher among individuals with CVD risk factors/conditions (ps < .01). There were differential associations between WMH and neuropsychological performance across ethnoracial groups (ps < .001), wherein associations were steeper in the NHW group than in the MA group. Lower educational level was associated with higher WMH volume in the NHW group (p < .001), but no association was seen in the MA group (p > .05).

Conclusions: Negative effects of pathological changes in the form of WMH on cognition may be less robust or consistent for MA adults than NHW adults. Furthermore, the impact of WMH on cognition in NHW adults may be mitigated by cognitive reserve related to educational attainment.

Keywords: Aging; Alzheimer’s disease; Hispanic or Latino; cardiovascular diseases; cognition; cognitive reserve.

Figure 1.

Ethnoracial group differences on composite z-scores for attention/EF (A) and memory (B), in addition to overall correlations of composite neuropsychological z-scores with age, ICV, and WMH volume (C). Abbreviations: EF = attention/EF; Mem = memory; ICV = intracranial volume; WMH = white matter hyperintensity.

Figure 2.

Differential associations between white matter hyperintensity (WMH) volume and neuropsychological performance in the MA and NHW groups for attention/EF (A) and memory (B). Interactions were assessed while accounting for age, sex, education, and intracranial volume (ICV).