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There is considerable controversy about the causes of the epidemics of chronic kidney disease of undetermined causes (CKDu), affecting agricultural communities in Central America, South Asia and possibly other parts of the world. In this Editorial, we argue that currently none of the suggested hypotheses have enough evidence, either for or against them, to draw firm conclusions.
What is CKDu and who gets it?
The common clinical features of CKDu are impaired kidney function in the absence of diabetes, primary glomerular nephritis and structural abnormality. CKDu exists in Central America1 and South Asia (India and Sri Lanka),2 3 and mainly affects rural male agricultural workers. It may also be occurring in other tropical/subtropical parts of the world, but standardised data are not available for comparison.4 We will, therefore, focus on the evidence from Central America and South Asia.
CKDu was first described in Central America in 2002,5 and in the rural population of the North Central Province of Sri Lanka in 2000.6 However, the estimates in Sri Lanka are not comparable with those from Central America because in the Sri Lankan prevalence studies to date, serum creatinine has only been performed in those with proteinuria, that is, in those with an albumin-creatinine ratio (ACR) ≥30 mg/g, whereas CKDu typically presents with either no or low-grade proteinuria in Central America.7 Therefore, valid prevalence estimates can currently only be obtained by identifying renal impairment in random population surveys.4 Other potential problems of international comparisons arise because the estimated glomerular filtration rate (eGFR) calculated from the serum creatinine is a function of ethnicity,8 exercise, muscle mass and meat consumption.
Causes of CKDu
Perhaps the most clearly established risk factor in both Central America and South Asia is that CKDu is more common in agricultural communities.9 In Central America, CKDu occurs frequently in sugar cane workers, but …
Contributors NP conceived and drafted the manuscript. BC revised the manuscript.
Funding This work was supported by grants from the UK Medical Research Council (MR/P02386X/1) and the Colt Foundation.
Competing interests None declared.
Provenance and peer review Commissioned; internally peer reviewed.
Patient consent for publication Not required.
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