Table 1

Descriptive data of workers with and without serum creatinine increase during sugarcane harvests at Ingenio San Antonio, Nicaragua, November 2017 to April 2019

Cases (cross-harvest SCr increase by 0.3 mg/dL)Controls (cross-harvest eGFRcrea change <10 mL/min/1.73m2)Case–control comparison
n*BaselineEnd-harvestCross-harvest trendn*BaselineEnd-harvestCross-harvest trendBaselineX-harvest differential trend
UnitMedian (IQR)p†Median (IQR)p†p†p†
AgeYears2226 (22–33)NA4928 (23–37)NA0.25NA
eGFRcreatininemL/min/1.73 m22295 (85–109)63 (57–71)<0.00149110 (81–123)108 (81–123)0.470.95<0.001
U-Creatininemmol/L226 (4–12)6 (4–10)0.63498 (5–13)5 (3–11)0.020.590.35
USGg/mL221.012 (1.008–1.017)1.012 (1.008–1.015)0.66491.012 (1.010–1.019)1.010 (1.006–1.016)0.260.720.80
S-Ferritinµg/L14‡137 (83–238)194 (114–316)<0.00128‡101 (75–205)99 (67–172)0.100.40<0.001
S-CRP§mg/L221.1 (0.6–3.3)6.4 (1.0–15)<0.001490.7 (0.4–2.2)1.0 (0.4–2.1)0.250.18<0.001
n (%)n (%)Case–control comparison, p¶
Cutter groupBurned cane2213 (59)4624 (52)0.62
Seed cane9 (41)22 (48)
Harvest2017–20182210 (45)4623 (50)0.80
2017–201912 (55)23 (50)
End-harvest samples on a Monday220461 (2)NA
  • *See the Methods section for full description of selection of workers for each analysis.

  • †From linear mixed model, see the Methods section.

  • ‡Ferritin levels were analysed in half the workers only and could not be determined for one case and one control due to insufficient sample volume.

  • §LOQ for CRP was 0.6 mg/dL.

  • ¶Fischer’s exact test.

  • CRP, C reactive protein; eGFR, estimated glomerular filtration rate; LOQ, limit of quantification; S, serum; SCr, serum creatinine; U, urine; USG, urine specific gravity.