Social Support and Mortality in Community-Dwelling Chinese Older Adults: The Mediating Role of Frailty

PURPOSE: Population ageing is posing an unprecedented challenge globally, necessitating a better understanding of modifiable factors and underlying pathways that could contribute to health and longevity in older age. We thus aim to investigate how the modifiable social support (and its various sources) is related to mortality among older adults, as well as whether and to what extent geriatric frailty plays a role in mediating the relationship. METHODS: We included 11,934 community-dwelling adults (≥65) from four waves of the Chinese Longitudinal Healthy Longevity Survey (2008–2018). Frailty was constructed by 44 health deficits, following a validated frailty index scale. Social support was measured using a sum score of three dimensions (family support, social service and social security) with 22 items. The outcome was all-cause mortality. Multivariate logistic or linear regression models were employed when appropriate to assess the associations among social support, frailty and mortality. Mediation analysis was applied to examine the role of frailty underlying the pathway between social support and mortality risk. RESULTS: A higher sum score of social support at baseline reduced mortality risk during the 10-year follow-up period (AOR=0.947, 95% CI=0.917~0.977). Amongst three sources of social support, family support and social security availability showed significantly protective effect against mortality, while social service revealed only non-significant effect. A higher level in the overall social support (β=−0.066, 95% CI=−0.113~-0.020) or family support (β=−0.121, 95% CI=−0.202~-0.039) was also significantly associated with decreased frailty. Meanwhile, frailty partially mediated the relationship of mortality with the overall social support and family support, where the proportion of mediation equaled to 17.1% and 20.5%, respectively. CONCLUSION: Social support could be associated with reduced risks for frailty and mortality, and such protective influences are especially manifested in its family support component among Chinese older adults. Frailty functions as potential mediator underlying the association of mortality with social support and family support. Our findings indicate the importance of social support as an integral part of geriatric care and underline the potential benefits of frailty assessment and intervention.