Association between Ambient Temperature and Nonaccidental Mortality in Liuzhou, China: A TimeSeries Study, 2014–2024

With the intensification of global climate change, the impact of environmental temperature on human health has attracted growing attention. This study aims to evaluate the effects of temperature on total non-accidental mortality, as well as mortality from cardiovascular and respiratory diseases, in Liuzhou City, China. Daily meteorological data and mortality records from 2014 to 2024 were collected for analysis. The cumulative relative risks (RRs) associated with non-optimal and extreme temperatures were estimated using a distributed lag nonlinear model (DLNM) combined with quasi-Poisson regression. Additionally, the attributable fractions (AFs) and attributable numbers (ANs) were calculated to assess the mortality burden attributable to non-optimal temperatures. Results indicated a significant U-shaped association between temperature and mortality, except in the 0–64 age group. The cumulative relative risk of extreme cold was 1.48 (95% CI: 1.32–1.66), while that of extreme heat was 1.22 (95% CI: 1.07–1.39). Non-optimal temperatures accounted for 9.69% (95% CI: 7.01–12.36) of total non-accidental deaths, with cold exposure contributing 7.19% (95% CI: 4.67–9.83) and heat exposure accounting for 2.49% (95% CI: 0.82–4.10). The findings indicate that exposure to non-optimal temperatures is significantly associated with increased mortality risk. Individuals aged 65 years and older demonstrated higher vulnerability to both cold and heat, highlighting the need for enhanced protective measures and targeted interventions for the elderly population.