Older adults life expectancy in China: Bayesian mortality estimation and spatially heterogeneous determinants

Life expectancy among the older adults is a key indicator of population health, yet provincial disparities in China remain substantial. Estimating older adults mortality is challenged by small sample sizes and spatial dependence, while the determinants of life expectancy may exhibit spatial heterogeneity.

Using data from the 2015 China National 1% Population Sample Survey, this study first employed Bayesian random effects models to estimate age-specific mortality rates for the older adults aged 60 + across 31 provinces, accounting for spatial correlation and small-sample smoothing. The abridged life table method was then used to calculate provincial life expectancy. Finally, multiple linear regression (MLR), spatial error model (SEM), spatial lag model (SLM), geographically weighted regression (GWR), and multiscale geographically weighted regression (MGWR) were compared to explore the spatially varying effects of socio-environmental factors, including old dependency ratio, healthcare resources, air pollution, education, and pension security.

The Bayesian model incorporating age-region interaction performed best. Older adults life expectancy exhibited a clear east-west gradient, with higher values in eastern and northeastern provinces and lower values in central and western regions. Global regression models showed that old dependency ratio and physician density were positively associated with life expectancy, while PM₁₀, education, and pension proportion were not significant. However, GWR suggested potential spatial heterogeneity: old dependency ratio and physician density showed patterns of stronger effects in northern China; PM₁₀ exhibited a more negative association in southwestern China; and pension security was significant only in northwestern provinces. GWR outperformed MGWR (R ² = 0.789 vs. 0.664), likely due to the small sample size, which makes MGWR prone to unstable bandwidth estimation.

Older adults life expectancy in China appears to be characterized by spatial disparities and potentially location-specific determinants. Uniform national policies may be insufficient to address regional health inequalities. Provincial governments might consider tailored strategies for older adults health resource allocation, with northern areas leveraging family and community support, southwestern regions prioritizing air pollution control, and northwestern areas expanding pension coverage.