Age-related amyloid beta dynamics modeled with the generalized additive model for location, scale, and shape (GAMLSS) across diverse populations: Cross-sectional trajectories and longitudinal validation

Abstract

INTRODUCTION We developed and validated age-related amyloid beta (A beta) positron emission tomography (PET) trajectories using a statistical model in cognitively unimpaired (CU) individuals. METHODS We analyzed 849 CU Korean and 521 CU non-Hispanic White (NHW) participants after propensity score matching. A beta PET trajectories were modeled using the generalized additive model for location, scale, and shape (GAMLSS) based on baseline data and validated with longitudinal data. Subgroup analyses examined apolipoprotein E (APOE) epsilon 4 and sex effects. RESULTS Age-related centile curves of A beta PET Centiloid values showed stable distributions in the lower percentiles, increasing with age in the upper percentiles. NHWs exhibited steeper A beta accumulation trajectories, particularly among APOE epsilon 4 carriers. Calibration with longitudinal data confirmed the reliability of this cross-sectional method. DISCUSSION We developed a statistical model of age-related A beta PET trajectories using baseline data, validated with longitudinal data. NHWs exhibited steeper trajectories than Koreans, suggesting population-specific differences in A beta accumulation.