Temporal relationship between ambient temperature and non-accidental mortality in Thailand as evidence of inadequate adaptation to heat

Abstract

Climate change and fluctuating temperature have become significant environmental issues impacting public health. However, the association between temperature and mortality in Thailand, particularly how this relationship changes over time, remains underexplored. This study aimed to investigate the time-varying association between ambient temperature and non-accidental mortality in Thailand, using the data from 2000 to 2020. The analyses of this study were separated into three sections. In the first section, the relationship between ambient temperature and mortality at the provincial level was explored using a combination of the distributed lag non-linear model (DLNM) and quasi-Poisson regression. In the second section, the province-specific estimates were pooled using random-effects meta-analysis to calculate the regional and national associations between ambient temperature and mortality. In the third section, the temporal association was assessed by dividing the data into two periods, which are 2000–2009 and 2010–2020. The same steps from the first and second sections were repeated for each predefined period to explore the temporal changes in the temperature-mortality relationship. Results indicated that the minimum mortality temperature (MMT) decreased from 28.7°C in 2000–2009 to 28.0°C in 2010–2020, and the mortality fractions attributable to heat had an increasing trend over time, while those attributable to cold followed a downward trend. This finding highlights the need for adaptive public health strategies, as heat-related mortality continues to evolve. Furthermore, this study provides critical insights for policymakers into protecting public health from the effects of climate change and temperature fluctuations in Thailand.