Medical comorbidities and ethnicity impact plasma Alzheimer's disease biomarkers: Important considerations for clinical trials and practice.

Abstract

Despite the clinical implementation, there remain significant gaps in our knowledge regarding the impact of race/ethnicity or common medical comorbidity on plasma Alzheimer's disease (AD) biomarkers. Plasma biomarkers of amyloid beta (Aβ)40, Aβ42 , total tau, and neurofilament light chain (NfL) were measured across cognitively normal Mexican Americans (n=445) and non-Hispanic Whites (n=520). Dyslipidemia was associated with elevated Aβ40 (P=.01) and Aβ42 (P=.001) while hypertension was associated with elevated Aβ40 (P=.003), Aβ42 (P<.001), and total tau (P=.002) levels. Diabetes was associated with higher Aβ40 (P<.001), Aβ42 (P<.001), total tau (P<.001), and NfL (P<.001) levels. Chronic kidney disease (CKD) was associated with elevations in Aβ40 (P<.001), Aβ42 (P<.001), total tau (P<.001), and NfL (P<.001) levels. Mexican Americans had significantly lower Aβ40 (P<.001) and higher total tau (P=.005) levels. Plasma AD biomarkers vary significantly in association with common medical comorbidities as well as ethnicity. These findings are important for those using these biomarkers in clinical practice and clinical trials.