Brain tissue volumes by APOE genotype and leisure activity-the AGES-Reykjavik Study

This study investigates the association of the APOE ε4 allele and leisure activity with brain tissue volumes, including white matter hyperintensities (WMH), in a population-based cohort of 4303 nondemented individuals, aged 66-96 years. APOE ε4 carriers were shown to have greater WMH and cerebrospinal fluid (CSF) volumes than noncarriers but smaller gray matter (GM) volumes. There was no significant difference in white matter (WM) and total brain parenchymal (TBP) volumes between APOE ε4 carriers and noncarriers. Tests for linear trend showed that individuals with lower leisure activity levels had greater WMH and CSF volumes, smaller TBP, WM and GM volumes than those with the highest levels of participation. The significant positive trend of the leisure activity with the brain tissue volumes was observed in the APOE ε4 carriers as well as in noncarriers after adjustment for demographic and health factors. These cross-sectional data suggest leisure activity is associated with tissue volumes in the brain irrespective of the APOE ε4 risk allele status.