Heat-induced kidney disease: Understanding the impact.

Research on Mesoamerican Nephropathy, chronic kidney disease of unknown cause and chronic kidney disease of nontraditional cause has been going on for more than 20 years. Thousands of manual workers, especially in agriculture, are affected. The disease has been reported in different countries and regions, not only from heat-stressed sugarcane cutters in Central America but also from other occupational groups with strenuous work in hot environments. The cause of this disease is still debated. A multitude of causative factors have been suggested, including agrochemicals, water quality, infections, and heavy metals. The evidence that heat stress is the major cause of kidney disease is convincing, whereas the support for alternative causes is weak. Associations between exposure and kidney damage are strong, consistent, and specific, occur after acute and chronic exposure, display dose-effect and dose-response relationships, are plausible, and coherent. Improving working conditions by providing hydration, rest, and shade to heat-stress-exposed workers is beneficial. Continued global warming will increase the number of people at risk for dangerous heat exposure and kidney disease.