Author(s):
Background: There has been increased research investigating the utility of plasma biomarkers of Alzheimer’s disease as diagnostic markers, predictors of risk and progression. Although there is extensive evidence pointing to sex differences in epidemiology, vulnerability, pathology and progression of AD there is a dearth of research on the impact of sex differences on Alzheimer’s related plasma biomarkers. There exists limited research on the impact of ethnicity on these biomarkers. Current research investigated sex differences in plasma biomarkers of amyloid (Aβ40, Aβ42), tau (total tau) and neurodegeneration (Neurofilament Light Chain (NFL)) in older Mexican Americans and non-Hispanic Whites.
Method: Sample included 292 male and 561 female Mexican Americans and 354 male and 430 female non- Hispanic Whites from Health and Aging Brain Study-Health Disparities (HABS-HD) study. Plasma samples were assayed using Simoa technology. Sex and ethnic differences for the biomarkers were assessed using ANOVAs co-varying for age.
Results and Discussion: Significant main effects were found for Aβ40 and tau for sex and ethnicity. Males had higher Aβ40 than females while females had higher tau. Non-Hispanic Whites had higher Aβ40 than Mexican Americans and lower total tau. Mexican American females had higher tau and lower NFL than Mexican American males. Non-Hispanic White females had higher tau than non-Hispanic White males who had higher Aβ40. Non- Hispanic White males had higher Aβ40 than Mexican American males who had higher tau and Aβ42/Aβ40 ratio. Non- Hispanic White females had higher Aβ40 than Mexican American females while Mexican American females had higher tau and Aβ42/Aβ40 ratio.
Conclusion: Findings reveal sex differences, ethnic differences, sex differences within ethnic groups and ethnic differences within the same sex in concentrations of plasma biomarkers. The use of AD plasma biomarkers as screening tools, diagnostic markers and trial endpoints need to consider sex and ethnic differences.
