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*	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.