Biomarkers of Kidney Injury among Nicaraguan Sugarcane Workers

Rebecca L. Laws, Daniel R. Brooks, Juan José Amador, Daniel E. Weiner, James S. Kaufman, Oriana Ramírez-Rubio, Alejandro Riefkohl, Madeleine K. Scammell, Damaris López-Pilarte, José Marcel Sánchez, Chirag R. Parikh, Michael D. McClean

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63 Scopus citations


Background In Central America, an epidemic of chronic kidney disease of unknown cause disproportionately affects young male agricultural workers. Study Design Longitudinal cohort study. Setting & Participants 284 sugarcane workers in 7 jobs were recruited from one company in northwestern Nicaragua. Blood and urine samples were collected before and near the end of the 6-month harvest season. Predictors Job category (cane cutter, seeder, seed cutter, agrichemical applicator, irrigator, driver, and factory worker); self-reported water and electrolyte solution intake. Outcomes & Measurements Changes in levels of urinary kidney injury biomarkers normalized to urine creatinine level, including neutrophil gelatinase-associated lipocalin (NGAL), interleukin 18 (IL-18), N-acetyl-β-d-glucosaminidase (NAG), and albumin; serum creatinine-based estimated glomerular filtration rate (eGFR). Results Mean eGFR was 113 mL/min/1.73 m2 and <5% of workers had albuminuria. Field workers had increases in NGAL and IL-18 levels that were 1.49 (95% CI, 1.06 to 2.09) and 1.61 (95% CI, 1.12 to 2.31) times as high, respectively, as in non-field workers. Cane cutters and irrigators had the greatest increases in NGAL levels during the harvest, whereas cane cutters and seeders had the greatest increases in IL-18 levels. Electrolyte solution consumption was associated with lower mean NGAL and NAG levels among cane cutters and lower mean IL-18 and NAG levels among seed cutters; however, there was no overall effect of hydration among all workers. On average, workers with the largest increases in NGAL and NAG levels during the harvest had declines in eGFRs of 4.6 (95% CI, 1.0 to 8.2) and 3.1 (95% CI, -0.6 to 6.7) mL/min/1.73 m2, respectively. Limitations Surrogate exposure measure, loss to follow-up. Conclusions Results are consistent with the hypothesis that occupational heat stress and volume depletion may be associated with the development of kidney disease, and future studies should directly measure these occupational factors. The presence of urine tubular injury markers supports a tubulointerstitial disease that could occur with repeated tubular injury.

Original languageEnglish (US)
Pages (from-to)209-217
Number of pages9
JournalAmerican Journal of Kidney Diseases
Issue number2
StatePublished - Feb 1 2016
Externally publishedYes


  • Chronic kidney disease (CKD)
  • Mesoamerican Nephropathy (MeN)
  • N-acetyl-β-d-glucosaminidase (NAG)
  • acute kidney injury (AKI)
  • estimated glomerular filtration rate (eGFR)
  • heat stress
  • interleukin 18 (IL-18)
  • neutrophil gelatinase-associated lipocalin (NGAL)
  • occupational safety
  • renal disease etiology
  • tubulointerstitial
  • urine tubular injury biomarker
  • volume depletion

ASJC Scopus subject areas

  • Nephrology


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