ASSOCIATION OF SOCIAL ISOLATION, HEALTHY LIFESTYLE, AND ALL-CAUSE MORTALITY AMONG RURAL OLDER ADULTS: JOINT EXPOSURE AND MEDIATION ANALYSES
Author(s)
Wenting Zhang, MPH.
Zhengzhou University, China, Zhengzhou, China.
Zhengzhou University, China, Zhengzhou, China.
OBJECTIVES: To examine the independent and joint associations of social isolation (SI) and healthy lifestyle (HLS) with all-cause mortality, and to identify behavioral mediation pathways among rural older adults.
METHODS: This prospective cohort study used two-wave panel data from 4,660 rural Chinese adults aged ≥65 years, with 298 all-cause deaths recorded during 2023-2025 follow-up. SI was measured using a validated 5-item social isolation index. HLS was categorized as unhealthy (0-1), intermediate (2), or ideal (3-4) based on four modifiable factors: diet, physical activity, smoking, and alcohol use. Cox proportional hazards models were used to estimate independent and joint effects, with sequential adjustment for sociodemographic and health-related covariates. KHB mediation analyses were conducted to assess the mediating roles of overall HLS, parallel multiple lifestyle behaviors, and individual behaviors.
RESULTS: In the fully adjusted model, SI was associated with higher mortality risk (HR=1.721, 95% CI: 1.295-2.289), whereas intermediate and ideal HLS were associated with lower risk (HR=0.676, 95% CI: 0.508-0.899; HR=0.627, 95% CI: 0.445-0.884). The highest mortality risk was observed among participants with both SI and unhealthy HLS (HR=2.347, 95% CI: 1.395-3.950). No significant multiplicative interaction was detected. Subgroup analyses showed a robust association for SI across strata, while the protective effect of HLS was generally consistent. KHB mediation analyses showed that the four lifestyle behaviors jointly mediated 19.06% of the SI-mortality association (indirect effect: β=0.094, P<0.001). Physical inactivity was the only statistically significant individual mediator, explaining 19.10% of the total effect, whereas diet, smoking, and alcohol use were not significant mediators.
CONCLUSIONS: SI and unhealthy lifestyle were independently associated with higher mortality, and their co-occurrence conferred the greatest risk. Physical inactivity appears to be the primary behavioral pathway linking SI to mortality, supporting targeted community interventions that integrate social connection programs with physical activity promotion for socially isolated rural older adults.
METHODS: This prospective cohort study used two-wave panel data from 4,660 rural Chinese adults aged ≥65 years, with 298 all-cause deaths recorded during 2023-2025 follow-up. SI was measured using a validated 5-item social isolation index. HLS was categorized as unhealthy (0-1), intermediate (2), or ideal (3-4) based on four modifiable factors: diet, physical activity, smoking, and alcohol use. Cox proportional hazards models were used to estimate independent and joint effects, with sequential adjustment for sociodemographic and health-related covariates. KHB mediation analyses were conducted to assess the mediating roles of overall HLS, parallel multiple lifestyle behaviors, and individual behaviors.
RESULTS: In the fully adjusted model, SI was associated with higher mortality risk (HR=1.721, 95% CI: 1.295-2.289), whereas intermediate and ideal HLS were associated with lower risk (HR=0.676, 95% CI: 0.508-0.899; HR=0.627, 95% CI: 0.445-0.884). The highest mortality risk was observed among participants with both SI and unhealthy HLS (HR=2.347, 95% CI: 1.395-3.950). No significant multiplicative interaction was detected. Subgroup analyses showed a robust association for SI across strata, while the protective effect of HLS was generally consistent. KHB mediation analyses showed that the four lifestyle behaviors jointly mediated 19.06% of the SI-mortality association (indirect effect: β=0.094, P<0.001). Physical inactivity was the only statistically significant individual mediator, explaining 19.10% of the total effect, whereas diet, smoking, and alcohol use were not significant mediators.
CONCLUSIONS: SI and unhealthy lifestyle were independently associated with higher mortality, and their co-occurrence conferred the greatest risk. Physical inactivity appears to be the primary behavioral pathway linking SI to mortality, supporting targeted community interventions that integrate social connection programs with physical activity promotion for socially isolated rural older adults.
Conference/Value in Health Info
2026-09, ISPOR Asia Pacific 2026, Bangkok, Thailand
Value in Health, Volume 55, Issue S1
Code
EPH27
Topic
Epidemiology & Public Health
Disease
SDC: Geriatrics