Baseline associations and relations over time
REGRESSION
To verify the expected inverse association between age and brain volume, we performed simple regression analyses between age and total hippocampal volume, cortical thickness, and total grey matter volume at baseline. Differences within the total group were investigated to determine whether total hippocampal volume, cortical thickness, and total grey matter volume changed over a time period of 6 months. We executed repeated measures analysis of variance including baseline and follow-up measurement of total hippocampal volume, cortical thickness, and total grey matter volume. Additionally, we used a multiple regression analysis to examine the association at baseline between physical fitness and total hippocampal volume, cortical thickness, and total grey matter volume, with age as covariate.