Background Agricultural work can expose workers to increased risk of heat strain and volume depletion due to repeated exposures to high ambient temperatures, arduous physical exertion and limited rehydration. These risk factors may result in acute kidney injury (AKI).

Methods We estimated incident AKI in a convenience sample of 283 agricultural workers based on elevations of serum creatinine between pre-and post-shift blood samples. Heat strain was assessed based on changes in core body temperature and heart rate. Volume depletion was assessed using changes in body mass over the work shift. Logistic regression models were used to estimate the associations of AKI with traditional risk factors (age, diabetes, hypertension and history of kidney disease) as well as with occupational risk factors (years in farm work, method of payment and farm task).

Results Thirty-five participants were characterised with incident AKI over the course of a work-shift (12.3 % 95% confidence interval [CI] 8.5% to 16.2%). Workers who experienced heat strain (PSI ≥ 7.5) had increased adjusted odds of AKI (adjusted odds ratio [AOR] 1.34, 95% CI: 1.04–1.74). Workers who were paid by the piece had AKI AOR of 4.24 (95% CI: 1.56–11.52).

Discussion Heat exposure and piece-rate work are associated with incident AKI after a single shift of agricultural work. Modifications to payment structures may help prevent AKI.