Systematic investigation of environmental exposures in young adults with declining kidney function in a population at risk of Mesoamerican Nephropathy (MeN)

Objectives: There is an epidemic of Mesoamerican Nephropathy (MeN) in Central America, where sugarcane production is prominent. Numerous causes have been proposed, but to date limited evidence supports any one hypothesis. A nested case-control study using biosamples from a rural, community-based follow-up study of 350 young adults from Northwest Nicaragua at risk of MeN, was conducted with the aim of characterizing the associations between urinary concentrations of metals, pesticides and mycotoxins, and decline in kidney function. Methods: Urine samples collected at baseline (pre-sugarcane harvest) and at the first 6-month follow-up (post-sugarcane harvest) visit were tested. Twelve metals and metalloids (Al, total As, Cd, Co, Cr, Cu, Hg, Mn, Pb, Se, Si and Sr) were analysed by inductively-coupled plasma-mass spectrometry. Twelve pesticides or their metabolites (2,4-D, 3-PBA, 4F3PBA, CFCA, DCCA, ETU, glyphosate, MCPA, OH-PYM, 5-OH-TBZ, TEB-OH and TCP), and two mycotoxins (OTA and CIT), were analysed by liquid chromatography coupled to mass spectrometry. Differences in the creatinine-corrected urinary concentrations of the measured exposures between outcome groups (participants with stable versus declining kidney function over a 2-year follow-up period) were examined. Results: Elevated levels of aluminium and total arsenic as well as metabolites of several pesticides were detected across the population. No differences were identified between the declining and stable groups in the levels of metals or pesticides tested. OTA and CIT were below the limit of detection. Conclusions: These findings provide evidence against the tested metals, metalloids, pesticides and mycotoxins as the primary cause(s) of MeN in Nicaragua. N/A