Associations of potential ADRD plasma biomarkers in cognitively normal volunteers

Introduction: This study examined the relationships between 13 novel blood-plasma biomarkers and dementia-related demographic and health factors in a cohort of 237 cognitively normal research volunteers whose average age was ≈82 years and who were 63% female. Methods: We regressed each biomarker on selected covariates to explore the associations between the biomarkers and selected factors to assess whether they may contribute to biomarker values. Post hoc sensitivity analyses were done with updated data and consistent variable sets for robustness and batch effects. Results: Biomarker concentrations were largely not associated with demographics or health conditions, but some expected associations (e.g., apolipoprotein E [APOE] status with amyloid beta [Aβ]42/Aβ40) were observed. Post hoc results remained similar to those of the main analysis. Discussion: The absence of strong associations between the biomarkers with age, gender, or medical conditions suggests that changes in these biomarkers, when observed, may be attributable to neuropathological changes. Highlights: Among N = 237 cognitively normal adults, we studied candidate Alzheimer's disease and related dementia (ADRD) plasma biomarkers. Biomarkers were largely not associated with demographic or health factors. Apolipoprotein E (APOE) status was associated with amyloid beta (Aβ)42/Aβ40 ratio. These results support hypotheses that plasma biomarkers are informative for ADRD.