Kidney Function, Self-Reported Symptoms, and Urine Findings in Nicaraguan Sugarcane Workers

Background: An epidemic of chronic kidney disease in Central America predominantly affects males working in certain industries including sugarcane. . Urinary tract infections are commonly diagnosed among men in Nicaragua, who often receive antibiotics and nonsteroidal anti-inflammatory drugs for urinary symptoms. Methods: We followed 251 male Nicaraguan sugarcane workers in seven job tasks over one harvest and measured urine dipstick parameters, kidney injury biomarkers, and estimated glomerular filtration rate (eGFR). We administered a questionnaire about urinary symptoms, health-related behaviors, and medication history. We cultured urine in a subset of workers. Results: The study population was composed of factory workers (22.7%), cane cutters (20.3%), irrigators (19.5%), drivers (16.3%), agrichemical applicators (11.6%), seeders/reseeders (6.0%), and seed cutters (3.6%). The mean age was 33.9 years and mean employment duration was 10.1 years. Cane cutters reported higher proportions of urinary-related symptoms compared with agrichemical applicators, irrigators, and seeders/reseeders. Seed cutters were more likely to take antibiotics (22.2%), while drivers and seeders/reseeders were more likely to take pain medications (26.8% and 26.7%, respectively). Proteinuria was uncommon, while dipstick leukocyte esterase was relatively common, especially among cane cutters, seed cutters, and seeders/reseeders (33.3%, 22.2%, and 21.4% at late-harvest, respectively). Dipstick leukocyte esterase at late-harvest was associated with a 12.9 mL/min/1.73m2 (95% CI: -18.7, -7.0) lower mean eGFR and 2.8 times (95% CI: 1.8, 4.3) higher mean neutrophil gelatinase-associated lipocalin (NGAL). In general, workers who reported urinary-related symptoms had higher mean kidney injury biomarker levels at late harvest. None of the workers had positive urine cultures, including those reporting urinary symptoms and/or with positive leukocyte esterase results. Amoxicillin, ibuprofen, and acetaminophen were the most commonly used medications. Conclusions: Job task is associated with urinary symptoms and dipstick leukocyte esterase. Urinary tract infection is misdiagnosed based on leukocyte esterase, which may be an important predictor of kidney outcomes.