Changes in kidney function among Nicaraguan sugarcane workers.

BACKGROUND There is an epidemic of chronic kidney disease (CKD) of unknown etiology in Central American workers. OBJECTIVES To investigate changes and job-specific differences in kidney function over a 6-month sugarcane harvest season, explore the potential role of hydration, and measure proteinuria. METHODS We recruited 284 Nicaraguan sugarcane workers performing seven distinct tasks. We measured urine albumin and serum creatinine and estimated glomerular filtration rate (eGFR). RESULTS eGFR varied by job and decreased during the harvest in seed cutters (-8·6 ml/min/1·73 m(2)), irrigators (-7·4 ml/min/1·73 m(2)), and cane cutters (-5·0 ml/min/1·73 m(2)), as compared to factory workers. The number of years employed at the company was negatively associated with eGFR. Fewer than 5% of workers had albumin-to-creatinine ratio (ACR) >30 mg/g. CONCLUSIONS The decline in kidney function during the harvest and the differences by job category and employment duration provide evidence that one or more risk factors of CKD are occupational.