Sex differential effect of parental longevity on the risk of dementia

The relationship of parental longevity with the aging brain-results from UK Biobank

A few studies report that parental longevity is associated with preserved cognition and physical function and lower risk of Alzheimer's disease. However, data on structural neuroimaging correlates of parental longevity and its spatial distribution are limited. This study aims to examine relationships of parental longevity with regional brain structure and to explore sex differences. We identified 12,970 UK Biobank participants (mean age = 64.4, 51.5%women) with data on parental longevity, regional gray matter volumes, and white matter microstructure. Participants were categorized based on whether at least one parent lived to age 85 or older or neither parent survived to age 85. Associations of parental longevity, maternal, and paternal longevity with each neuroimaging marker of interest were examined using linear regression, adjusted for demographics, APOE e4 status, lifestyle, and cardiometabolic conditions. Compared to participants whose both parents died before 85 (43%), those with at least one parent surviving to 85 (57%) had greater volumes in hippocampus, parahippocampal gyrus, middle temporal lobe, and primary sensorimotor cortex and had lower mean diffusivity in posterior thalamic radiation and uncinate fasciculus. Associations were prominent with maternal longevity. Adjustment for cardiometabolic conditions did not affect observed associations except mean diffusivity in posterior thalamic radiation. There were no structural differences in other areas. Parental longevity is associated with preserved brain structure localized in primary sensorimotor cortex and temporal areas including hippocampus. These relationships are prominent with maternal longevity. Longitudinal studies are needed to determine whether changes in these brain structures account for the association between parental longevity and dementia.