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Heat strain, volume depletion and kidney function in California agricultural workers
  1. Sally Moyce1,
  2. Diane Mitchell2,
  3. Tracey Armitage2,
  4. Daniel Tancredi3,
  5. Jill Joseph1,
  6. Marc Schenker2
  1. 1Betty Irene Moore School of Nursing, University of California, Davis, Sacramento, California, USA
  2. 2Department of Public Health Sciences, University of California, Davis, Davis, California, USA
  3. 3Department of Pediatrics, University of California, Davis, Davis, California, USA
  1. Correspondence to Dr Sally Moyce, Betty Irene Moore School of Nursing, University of California, Davis, 4610 X Street, Sacramento, CA 95817, USA; sallymoyce{at}


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 AKI cumulative incidence in a convenience sample of 283 agricultural workers based on elevations of serum creatinine between preshift and postshift 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 35 participants were characterised with incident AKI over the course of a work shift (12.3%). Workers who experienced heat strain had increased adjusted odds of AKI (1.34, 95% CI 1.04 to 1.74). Piece rate work was associated with 4.24 odds of AKI (95% CI 1.56 to 11.52). Females paid by the piece had 102.81 adjusted odds of AKI (95% CI 7.32 to 1443.20).

Discussion Heat strain and piece rate work are associated with incident AKI after a single shift of agricultural work, though gender differences exist. Modifications to payment structures may help prevent AKI.

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  • Correction notice This paper has been updated since it first published online. The article type has been changed.

  • Contributors All authors contributed to the work of this manuscript. SM conceptualised and oversaw the research and drafted the manuscripts. DM oversaw data collection and data management. TA assisted with data analysis. DT oversaw statistical analysis. JJ contributed to study design and manuscript preparation. MS oversaw all study procedures.

  • Funding The work reported here was supported by dissertation grants from the UC Global Health Initiative, the Health Initiative of the Americas, and the Western Center for Agricultural Safety and Health.

  • Competing interests None declared.

  • Patient consent Obtained.

  • Ethics approval All study procedures were reviewed and approved by the Institutional Review Board at the University of California, Davis.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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