Association between intra-individual changes in social network diversity and global cognition in older adults: Does...

Although qualitative aspects of interpersonal networks, such as diversity or closeness, can protect the health of older adults, their association with cognitive health remains unclear. This study examined the concurrent and time-lagged association between intra-individual changes in global cognition and social network diversity, while considering emotional closeness.

In this 10-year study, we obtained six-wave, biennial data from the National Institute for Longevity Sciences, Longitudinal Study of Aging. Data from 808 community-dwelling, cognitively intact adults aged 65 or older at baseline were analyzed. Global cognition was assessed using the Mini-Mental State Examination (MMSE). Social network diversity scores were assessed using a social convoy model, comprising three closeness levels: inner (closest), middle (second closest), and outer (least close).

The mean age of the respondents was 72.0 ± 4.4 years at baseline, and 50.1% were male. A fixed-effects model showed that intra-individual change in total (coefficients, B: 0.10; standard error [SE]: 0.05; p = .042) and inner (B: 0.25; SE: 0.07; p < .001) social network diversity was significantly associated with MMSE score decline, even after adjusting for covariates. Yet, in time-lagged models, diversity and MMSE score changes were not significantly associated during the subsequent two years.

Older adults' global cognition declined when the diversity of their closest social network decreased. This may be a promising marker for early cognitive decline in older adults. Indeed, their closest networks are relatively unlikely to decline as part of normal aging or diseases except dementia.