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

ABSTRACT

INTRODUCTION: 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. METHODS: Plasma biomarkers of amyloid beta (Aß)40, Aß42 , total tau, and neurofilament light chain (NfL) were measured across cognitively normal Mexican Americans (n = 445) and non-Hispanic Whites (n = 520). RESULTS: Dyslipidemia was associated with elevated Aß40 (P = .01) and Aß42 (P = .001) while hypertension was associated with elevated Aß40 (P = .003), Aß42 (P < .001), and total tau (P = .002) levels. Diabetes was associated with higher Aß40 (P < .001), Aß42 (P < .001), total tau (P < .001), and NfL (P < .001) levels. Chronic kidney disease (CKD) was associated with elevations in Aß40 (P < .001), Aß42 (P < .001), total tau (P < .001), and NfL (P < .001) levels. Mexican Americans had significantly lower Aß40 (P < .001) and higher total tau (P = .005) levels. DISCUSSION: 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.