Environmental metal exposures and kidney function of Guatemalan sugarcane workers

Abstract

Background: Exposure to environmental metals can cause nephrotoxicity. There is an international epidemic of chronic kidney disease of unknown cause (CKDu), referred to in Latin America as Mesoamerican Nephropathy (MeN). Whether metal exposures contribute to kidney dysfunction in populations at-risk for CKDu remains unresolved.Methods: We examined the presence and concentrations of urinary heavy metals (arsenic, cadmium, and nickel) in 201 sugarcane cutters in Guatemala at three time points over one year. We explored relationships between urine metal concentrations and markers of kidney function by calculating β estimates and 95% confidence intervals of kidney function markers using multivariable linear mixed-effect models.Results: Urine arsenic, cadmium, and nickel were detected in the majority of the 332 urine samples. After adjusting for age, systolic blood pressure, Hemoglobin A1c, body mass index, time of collection, and urine creatinine, higher urine cadmium was inversely associated with estimated glomerular filtration rate (eGFR) (β: -6.11, 95% Confidence Interval [CI]: -8.83, -3.39) and positively associated with neutrophil gelatinase-associated lipocalin (NGAL) (β: 2.73, 95% CI: 1.03, 4.43). Higher urine arsenic was inversely associated with eGFR (β: -4.55, 95% CI: -7.08, -2.01).Conclusions: Our findings are suggestive of kidney toxicity due to metal exposure, as measured by urinary cadmium and arsenic.