Social and family health as dual determinants of quality of life among older adults with chronic disease: a population-based study

Social health and family health are critical resources for managing long-term illness and daily functioning among older adults with chronic diseases, with significant implications for quality of life. However, the extent to which variations in these domains contribute to quality of life and potential disparities across population groups remains unclear. Data were collected between July and September 2024 through multi-stage stratified sampling across China, including 6,648 individuals aged 60 years or older with chronic diseases. Quality of life was measured via the EuroQol 5-Dimension 5-Level questionnaire. Social health was measured using the Social Isolation Scale, and family health using the Family Health Scale-Short Form. Multivariable linear regression models with marginal effects were used to examine associations between social health, family health, and quality of life. Better social health (β = 0.100, 95% CI: 0.080 to 0.121) and family health (β = 0.056, 95% CI: 0.044 to 0.074) were both associated with higher quality of life. The marginal effect of family health decreased as scores increased, declining from 0.113 (95% CI: 0.087–0.139) at Q1 (25th percentile) to 0.085 (95% CI: 0.059–0.110) at Q3 (75th percentile). A similar attenuation was observed for social health from Q1 (β = 0.035, 95% CI: 0.015–0.054) to Q2 (β = 0.024, 95% CI: 0.009–0.038), with no significant effect at Q3 (β = 0.013, 95% CI: -0.003–0.029). Furthermore, family health was positively associated with quality of life only among females (β = 0.037, 95% CI: 0.016 to 0.058), individuals with lower socioeconomic status (β = 0.054, 95% CI: 0.027 to 0.080), and those without multimorbidity (β = 0.027, 95% CI: 0.010 to 0.045), whereas social health showed consistent positive associations across all subgroups (all P < 0.001). Social and family health are central to quality of life among older adults with chronic diseases, with family health showing stronger effects among women, socioeconomically disadvantaged, and relatively healthier groups. These findings underscore the need for equity-oriented strategies that strengthen social and family health, with targeted attention to vulnerable subpopulations.