Emerging health threats in a changing climate: global trends in the burden of noncommunicable diseases associated with non-optimal temperature

Introduction Under climate change, non-optimal temperature is a key environmental risk for noncommunicable diseases (NCDs), but global evidence comparing disease-specific burdens across climate zones and development levels remains limited. We assessed attributable NCD burden during 1990–2021.Theory We used a conceptual framework linking temperature exposure with NCD burden, integrating low and high temperature exposure, socio-demographic index (SDI), climate-zone stratification and age-period-cohort (APC) modelling to explain regional heterogeneity.Method Using Global Burden of Disease 2021 data, we calculated age-standardised death rates and age-standardised disability-adjusted life-year (DALY) rates for NCDs attributable to low, high and non-optimal temperature. We examined associations with mean annual temperature, SDI and climate zones, and used APC models to estimate age, period and cohort effects.Results Mortality and DALY burdens were higher in cold regions, whereas diabetes and kidney disease burdens were greater and worsening in hot regions. During 1992–2021, low-middle SDI regions improved most slowly, with net drift values of −0.137% for NCD mortality and −0.127% for DALY rates. High-temperature-related cardiovascular burdens increased in all regions (net drift >0%). After age 50, between-SDI disparities in NCD mortality widened. In low-middle SDI regions, low-temperature-related diabetes and kidney disease risks increased after 2002–2006.Discussion The burden of NCDs attributable to non-optimal temperature showed spatial inequality. Climate adaptation should prioritise low-middle SDI regions, older adults, worsening diabetes and kidney disease burdens in hotter regions, and heat-related cardiovascular risks, while strengthening early warning systems, climate-resilient infrastructure, integrated chronic disease management, and mechanistic and intervention research.