Heat stress exposure and incidence of chronic kidney disease.

Long-term repeated heat stress may contribute to chronic kidney disease (CKD). In this ecological study, we examined country-level associations between heat stress exposure and CKD incidence using data from 174 countries during 1990-2021. Annual numbers of days with four heat stress levels (moderate, strong, very strong, and extreme) were assessed using the Universal Thermal Climate Index. A weighted heat stress score was generated from these four levels. Linear mixed-effects models were used to evaluate the associations. Each additional day of moderate, strong, very strong, and extreme heat stress was associated with increases of 0.088 (95% confidence interval [CI]: 0.035-0.140), 0.095 (0.047-0.142), 0.097 (0.036-0.159), and 0.782 (0.643-0.921) incident cases per 100,000 population, respectively. The weighted heat stress score was consistently associated with an increased incidence of CKD. These findings may imply that attention should be paid to the potential disease burden of heat-related CKD.