Global, regional, and national temporal trends in the prevalence of environmental heat and cold exposure among older adults aged 60-99 years, 1990-2021: an age-period-cohort analysis based on the Global Burden of Disease Study 2021.

BACKGROUND: Environmental heat and cold exposure (EHCE), a threat magnified by global climate change, is a major preventable cause of death in older adults worldwide but remains an under-recognized public health problem. To address this gap, this study aimed to analyze long-term trends in the prevalence of EHCE in the older adults from 1990 to 2021, as well as age, period, and cohort effects. METHODS: Using data from the Global Burden of Disease Study 2021, we conducted an age-period-cohort (APC) analysis of the prevalence of EHCE among the older adults aged 60-99 years across 204 countries and territories. The age-standardized prevalence rate (ASPR) was calculated, and the net drift and local drift were used to assess overall and age-specific trends. The APC model was employed to disentangle the effects of age, period, and birth cohort on the changes in the prevalence of EHCE. All analyses were stratified by sociodemographic index (SDI) levels to account for regional differences. RESULTS: From 1990 to 2021, the number of global EHCE cases among the older adults increased by 52.48%, reaching 4.43 million (95% UI: 3.88 to 5.10 million), while the ASPR decreased by 33.60%. The global net drift in the prevalence of EHCE was -1.48% annually, with significant regional variations: high SDI regions experienced the smallest decline (-0.17% per year), whereas high-middle SDI regions experienced the greatest decline (-2.95% per year). APC analysis revealed that age effects were most pronounced in high SDI regions. Conversely, in high-middle SDI regions, socioeconomic improvements and strengthened healthcare systems contributed to a negative correlation between age and the risk of EHCE. Period and cohort effects demonstrated a general decline in the prevalence of EHCE, with the most significant improvements in high-middle SDI regions. CONCLUSIONS: Although the number of EHCE cases has increased because of population growth and aging, the relative burden of EHCE has declined globally as a result of improvements in public health infrastructure and climate adaptation measures. However, high SDI regions face persistent challenges and a slower decline in the prevalence of EHCE, highlighting the need for targeted interventions.