AUTHOR=Jockwitz Christiane , Mérillat Susan , Liem Franziskus , Oschwald Jessica , Amunts Katrin , Jäncke Lutz , Caspers Svenja 

TITLE=Generalizing Longitudinal Age Effects on Brain Structure – A Two-Study Comparison Approach

JOURNAL=Frontiers in Human Neuroscience

VOLUME=Volume 15 - 2021

YEAR=2021

URL=https://www.frontiersin.org/journals/human-neuroscience/articles/10.3389/fnhum.2021.635687

DOI=10.3389/fnhum.2021.635687

ISSN=1662-5161

ABSTRACT=Cross-sectional studies indicate that normal aging is accompanied by decreases in brain structure. Especially during older ages, however, high inter-individual variability might obscure the intra-individual trajectories of the aging process. Further, methodological differences in study designs, e.g. brain metrics assessed, hamper the generalizability of study results. Therefore, the current study aimed to compare longitudinal age-related changes in brain structure (measured through cortical thickness) in two large independent samples of healthy older adults (n = 161 each); the Longitudinal Healthy Aging Brain (LHAB) database project at the University of Zurich; Switzerland and 1000BRAINS at the Research Center Juelich, Germany. Annual percentage changes in the two samples revealed stable to slight decreases in cortical thickness over time. After correction for major covariates, i.e. baseline age, sex, education, and image quality, sample differences were only marginally present.  Results suggest that general trends across time might be generalizable over independent samples, assuming the same methodology is used and similar sample characteristics are present.