Agricultural behaviors and exposures as risk factors for chronic kidney disease in northwest Nicaragua

Chronic Kidney Disease of Unknown Etiology (CKDu, aka Mesoamerican Endemic Nephropathy (MEN)) has emerged as a devastating epidemic in Guanacastal Sur, Nicaragua. The cause of this epidemic is unknown, but may be linked to multi-factorial dietary, environmental, and occupational exposures. Past studies indicate that as many as 70% of men in some communities have the disease and that an occupational history in sugar cane is a significant risk factor. This study investigates the etiological linkage between agricultural work and CKDu, with the goal of identifying specific occupational behaviors and exposures associated with development of the disease. We administered questionnaires on nutrition, hygiene, medical history, and household exposures; collected blood and urine samples to measure serum creatinine, Hemoglobin A1c (HbA1c), and lipid profile; measured blood pressure; and took physical measures to evaluate metabolic disorders in 332 individuals living in Guanacastal Sur. We administered questionnaires on the working environment to the 151 individuals in this study population with an occupational history in agriculture. Preliminary analyses indicate a prevalence of glomerular filtration rate (eGFR)<60, indicating potential CKDu, of 8% among females and 36% among males. Neither HbA1c nor mean arterial pressure contributed significantly to variations in eGFR. Increased lifetime days cutting sugar cane cutter during the dry season was associated with significantly lower estimated eGFR. These results corroborate trends found in previous studies of CKDu, and ongoing analyses should help to elucidate the roles that pesticide and fertilizer exposure; dehydration; sugar intake, nutrition, and metabolic status; comorbidities; and nephrotoxic medication use play in the etiology of this disease.