Disparities in heatwave-related mortality and socioeconomic burden by single-person households in China

With heatwaves becoming more severe under climate change, elderly adults face rising mortality risks, but it remains unclear whether residence in a single-person household marks an additional vulnerability. Using data from three nationwide cohorts in China, we examine disparities in heatwave-related all-cause mortality among individuals aged 45 years and older and assess the associated health and socioeconomic burden. Among 49,912 participants from 210 cities, heatwave exposure is associated with higher all-cause mortality across alternative definitions. The association is stronger among individuals residing in single-person households than those residing in multi-person households. In 2020, heatwaves were associated with 68,922 attributable deaths in China, with more than 25% occurring among individuals residing in single-person households, corresponding to 63.46 billion USD. Future warming could widen the burden disparities through the 2080s. These findings identify single-person households as an emerging vulnerability factor for heatwave-health risk assessment and equitable climate adaptation in aging societies.