Social network characteristics moderate associations between cortical thickness and cognitive functioning in older adults.

INTRODUCTION: Prior research suggests that the strength of association between Alzheimer's disease (AD) pathology and lower cognitive performance is influenced by modifiable psychosocial factors, such as social network size. However, little is known about distinct social relationship types.
METHODS: The current cross-sectional study used data from the Washington Heights-Inwood Columbia Aging Project to examine whether social network characteristics (i.e., total size, spouse/partner, number of children, other relatives, friends) moderate associations between cortical thickness in regions implicated in AD and cognitive performance.
RESULTS: Lower cortical thickness was associated with worse global cognition among individuals with smaller friend networks, but not among individuals with larger friend networks. This pattern of results was most prominent for language and speed/executive functioning.
DISCUSSION: Longitudinal and intervention studies are needed to determine whether these cross-sectional findings reflect a protective effect of later-life friendships for maintaining cognitive performance in the context of poorer brain health.