title: Biomarkers of Kidney Injury Among Nicaraguan Sugarcane Workers.
abstract: BACKGROUND
  In Central America, an epidemic of chronic kidney disease of unknown cause disproportionately affects young male agricultural workers.
  
  
  METHODS
  Longitudinal cohort study.
  
  
  METHODS
  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.
  
  
  METHODS
  Job category (cane cutter, seeder, seed cutter, agrichemical applicator, irrigator, driver, and factory worker); self-reported water and electrolyte solution intake.
  
  
  METHODS
  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 m(2) 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 m(2), respectively.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Environmental Health, Boston University School of Public Health, Boston, MA. Electronic address: rlaws@bu.edu.
authors.forename: Rebecca L
authors.initials: RL
authors.lastname: Laws
authors.affiliation: Department of Epidemiology, Boston University School of Public Health, Boston, MA.
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Brooks
authors.affiliation: Department of Epidemiology, Boston University School of Public Health, Boston, MA.
authors.forename: Juan José
authors.initials: JJ
authors.lastname: Amador
authors.affiliation: Division of Nephrology, Department of Medicine, Tufts Medical Center and Tufts University School of Medicine, Boston, MA.
authors.forename: Daniel E
authors.initials: DE
authors.lastname: Weiner
authors.affiliation: Research Service, VA New York Harbor Healthcare System, New York, NY; Department of Medicine, New York University School of Medicine, New York, NY.
authors.forename: James S
authors.initials: JS
authors.lastname: Kaufman
authors.affiliation: Department of Epidemiology, Boston University School of Public Health, Boston, MA; Preventive Medicine and Public Health Department, Universidad Autónoma de Madrid, Madrid, Spain.
authors.forename: Oriana
authors.initials: O
authors.lastname: Ramírez-Rubio
authors.affiliation: Department of Epidemiology, Boston University School of Public Health, Boston, MA.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Riefkohl
authors.affiliation: Department of Environmental Health, Boston University School of Public Health, Boston, MA.
authors.forename: Madeleine K
authors.initials: MK
authors.lastname: Scammell
authors.affiliation: Department of Epidemiology, Boston University School of Public Health, Boston, MA.
authors.forename: Damaris
authors.initials: D
authors.lastname: López-Pilarte
authors.affiliation: Department of Epidemiology, Boston University School of Public Health, Boston, MA.
authors.forename: José Marcel
authors.initials: JM
authors.lastname: Sánchez
authors.affiliation: Section of Nephrology, Department of Medicine, Yale University and VA Medical Center, New Haven, CT; Program of Applied Translational Research, Department of Medicine, Yale University, New Haven, CT.
authors.forename: Chirag R
authors.initials: CR
authors.lastname: Parikh
authors.affiliation: Department of Environmental Health, Boston University School of Public Health, Boston, MA.
authors.forename: Michael D
authors.initials: MD
authors.lastname: McClean
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood / Q000652:urine; D015331:Cohort Studies; D003681:Dehydration / Q000097:blood / Q000453:epidemiology / Q000652:urine; D000067565:Farmers; D005260:Female; D018869:Heat-Shock Response / Q000502:physiology; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009527:Nicaragua / Q000453:epidemiology; D016273:Occupational Exposure / Q000009:adverse effects*; D051436:Renal Insufficiency, Chronic / Q000097:blood* / Q000453:epidemiology / Q000652:urine*; D031786:Saccharum; D055815:Young Adult
chemical_list: D015415:Biomarkers
keywords: 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