8106733 Is chronic kidney disease of unknown cause (CKDu) an occupational or environmental disease?

<h3>Objectives</h3> Epidemics of Chronic Kidney Disease of undetermined cause (CKDu) are affecting agricultural communities in Central America, and South Asia. A number of possible causes have been suggested, including: heat/dehydration, pesticides, water contamination, and infections. We have assessed the potential role of these exposures in explaining the population distribution, and individual risks, for CKDu. <h3>Material and Methods</h3> We used a combination of: (i) standardized population-level surveys of the prevalence of low estimated Glomerular Filtration Rate (eGFR), a surrogate for prevalent CKDu; and (ii) cohort studies in Nicaragua, India and Sri Lanka assessing individual-level risk factors for disease onset. <h3>Results</h3> Globally, there is strong evidence of regional epidemics of CKDu in Central America and South Asia, but little evidence of high CKDu prevalence in other parts of the world. In Central America, CKDu occurs frequently in sugar cane workers, but also in other occupational groups, including other agricultural workers, fishermen, miners, and construction workers. It also occurs in women, particularly in some areas of South Asia. Furthermore, there are several examples of occupational populations with high levels of exposure to heat stress and/or pesticides, which do not show increased prevalence of CKDu. <h3>Conclusions</h3> With regards to disease onset, most of the hypotheses which have been proposed have little or no support from population studies, and it is still not clear whether the key risk factors are occupational or environmental, or a combination. At the individual level, there is evidence for disease onset occurring across the population (not just in specific occupational groups), and this associates with symptoms of constitutional upset. Taken together, the evidence suggests an as yet undefined cause of disease onset (which could be occupational and/or environmental), with important occupational risk factors (including heat stress) for disease progression.