Global associations between extreme temperature events and childhood cancer incidence and mortality

Abstract

Although extreme temperatures are recognized as an environmental threat, their contribution to the global burden of childhood cancer remains poorly quantified. We aimed to estimate childhood cancer incidence and mortality rates associated with heat and cold exposures across 204 countries and territories from 1990 to 2021. Daily ambient temperature series from the U.S. National Oceanic and Atmospheric Administration meteorological stations were used to calculate location-specific cumulative heat exposure, cumulative cold exposure, heat waves and cold waves. National estimates of childhood cancer burden among individuals aged 0-19 years in 204 countries and territories were extracted from the Global Burden of Disease 2021 repository. Linear mixed-effects models were fitted to quantify exposure-outcome associations. Subtype-specific analyses were performed for seven solid tumors. A marked global increase in heat-wave frequency has occurred since 1990, particularly in Eastern Europe, Africa, and South Asia. Each additional heat-wave event was significantly associated with 0.32 additional cases per 100,000 population and 19.79 additional deaths per 10,000,000 population. The association with incidence appeared stronger in females than in males. The association of extreme temperatures was predominantly observed in low and low-middle socio-demographic index nations and countries with < 300 million inhabitants, although the heat-wave-associated effect estimate was larger in nations with > 300 million residents. Malignant neoplasms of bone and articular cartilage showed the strongest associations with heat waves. The influence of temperature on the association with childhood cancer burden has strengthened, exhibiting an overall upward trajectory over the study period. This first global analysis demonstrates that extreme temperatures, particularly heat, impose a substantial burden on childhood cancer.