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* | Baseline | End-harvest | Cross-harvest trend | n* | Baseline | End-harvest | Cross-harvest trend | Baseline | X-harvest differential trend | ||
| Unit | Median (IQR) | p† | Median (IQR) | p† | p† | p† | |||||
| Age | Years | 22 | 26 (22–33) | NA | 49 | 28 (23–37) | NA | 0.25 | NA | ||
| eGFRcreatinine | mL/min/1.73 m2 | 22 | 95 (85–109) | 63 (57–71) | <0.001 | 49 | 110 (81–123) | 108 (81–123) | 0.47 | 0.95 | <0.001 |
| U-Creatinine | mmol/L | 22 | 6 (4–12) | 6 (4–10) | 0.63 | 49 | 8 (5–13) | 5 (3–11) | 0.02 | 0.59 | 0.35 |
| USG | g/mL | 22 | 1.012 (1.008–1.017) | 1.012 (1.008–1.015) | 0.66 | 49 | 1.012 (1.010–1.019) | 1.010 (1.006–1.016) | 0.26 | 0.72 | 0.80 |
| S-Ferritin | µg/L | 14‡ | 137 (83–238) | 194 (114–316) | <0.001 | 28‡ | 101 (75–205) | 99 (67–172) | 0.10 | 0.40 | <0.001 |
| S-CRP§ | mg/L | 22 | 1.1 (0.6–3.3) | 6.4 (1.0–15) | <0.001 | 49 | 0.7 (0.4–2.2) | 1.0 (0.4–2.1) | 0.25 | 0.18 | <0.001 |
| n (%) | n (%) | Case–control comparison, p¶ | |||||||||
| Cutter group | Burned cane | 22 | 13 (59) | 46 | 24 (52) | 0.62 | |||||
| Seed cane | 9 (41) | 22 (48) | |||||||||
| Harvest | 2017–2018 | 22 | 10 (45) | 46 | 23 (50) | 0.80 | |||||
| 2017–2019 | 12 (55) | 23 (50) | |||||||||
| End-harvest samples on a Monday | 22 | 0 | 46 | 1 (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.