Heat exposure and self-rated health in older Chinese adults: the mediating roles of chronic disease and intergenerational support, 2008-2018 CLHLS.

Background: Under the dual pressures of global warming and accelerated population aging, rising temperatures pose a particularly serious threat to the older population. However, systematic evidence on the heat exposure-response pathway is still scarce. This study aims to explore the effects of heat exposure on self-rated health and its pathways in older adults in China. We predicted that heat exposure would reduce the self-rated health of older adults, and that chronic diseases and intergenerational support would mediate this effect.

Methods: We linked health data from 9,670 participants in the Chinese Longitudinal Healthy Longevity Survey (CLHLS, 2008-2018 waves) with meteorological records from the National Climatic Data Center (NCDC). Individual fixed-effects models were employed to disentangle acute versus cumulative thermal effects, while Bootstrap-mediated path analysis quantified the mediating mechanisms involving chronic disease proliferation and deterioration of intergenerational support.

Results: Heat exposure has a time effect on the health risk of older adults, and long-term heat exposure (β = -0.156, p < 0.01; β = -0.003, p < 0.01) significantly reduces self-rated health through the cumulative effect of health disadvantages than short-term exposure (β = 0.004, p < 0.1; β = -0.001, p > 0.1). The increase in the number of chronic diseases (β = 0.260, p < 0.05) and the weakening of children's intergenerational support (β = -0.052, p < 0.01; β = -0.023, p < 0.01) constitute a mediating pathway at individual and household level separately.

Conclusion: We found that chronic diseases and intergenerational support from children mediated the effect of heat exposure on the deterioration of self-rated health in older adults. Empirical evidence substantiates the necessity for a tiered intervention framework encompassing: individual-level chronic disease co-management protocols; household-driven initiatives to reinforce intergenerational support. This stratified approach alleviates bioclimatic risks through coordinated physiological adaptation and optimization of kinship network.