Exploring longitudinal relationships among Alzheimer's disease biomarkers.

INTRODUCTION

While most studies of Alzheimer's disease (AD) examine cross-sectional relationships among biomarkers, longitudinal relationships are also highly relevant.

METHODS

This study in the Alzheimer's Disease Neuroimaging Initiative cohort (n = 373) used non-parametric Spearman correlations to explore the relationships of baseline values and rates of change in plasma biomarkers and rates of change in key AD outcomes.

RESULTS

Compared to rates of change of plasma biomarkers, baseline values of plasma biomarkers were more strongly associated with rates of change in key AD outcomes. Change in amyloid positron emission tomography (PET) was most strongly associated with baseline values of amyloid beta (Aβ)42/Aβ40 and phosphorylated tau (p-tau)217, especially in amyloid PET--negative individuals. Changes in cortical thickness and measures of cognition were most strongly associated with baseline p-tau217, especially in amyloid PET-positive individuals.

DISCUSSION: Baseline p-tau217 is associated with rates of change of amyloid pathology and cognition. Visualization tools were developed to enable researchers to explore AD biomarker relationships.