Objectives To assess if improvement of working conditions related to heat stress was associated with improved kidney health outcomes among sugarcane harvest workers in Chichigalpa, Nicaragua, a region heavily affected by the epidemic of chronic kidney disease of non-traditional origin.
Methods Based on our findings during the 2017–2018 harvest (harvest 1), recommendations that enhanced the rest schedule and improved access to hydration and shade were given before the 2018–2019 harvest (harvest 2). Actual work conditions during harvest 2 were then observed. Serum creatinine (SCr) was measured before and at end-harvest, and cross-harvest changes in estimated glomerular filtration rate (eGFR) and incident kidney injury (IKI, ie, SCr increase by ≥0.30 mg/dL or ≥1.5 times the baseline value) were compared between harvest 1 and harvest 2 for three jobs with different physical workloads using regression modelling. Workers who left during harvest were contacted at home, to address the healthy worker selection effect.
Results In burned cane cutters, mean cross-harvest eGFR decreased 6 mL/min/1.73 m2 (95% CI 2 to 9 mL/min/1.73 m2) less and IKI was 70% (95% CI 90% to 50%) lower in harvest 2 as compared with harvest 1 data. No such improvements were seen among seed cutters groups with less successful intervention implementation.
Conclusion Kidney injury risk was again elevated in workers with strenuous jobs. The results support further efforts to prevent kidney injury among sugarcane workers, and other heat-stressed workers, by improving access to water, rest and shade. The distinction between design and implementation of such interventions should be recognised.
- international occupational health
- intervention studies
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JG and EH contributed equally.
Contributors JG, IW, DHW and CW conceived the study and CW prepared the first protocol draft. The final protocol was produced with essential input from DHW, JG, IW and KJ. IW was responsible for all field work logistics and participated in data collection together with CW, SP, EAM and JG. UE and JA were responsible for laboratory analyses. CW and EH were responsible for data management and EH performed the statistical analyses. DHW was the principal investigator and supervised the project.
Funding This research was funded via the Adelante Initiative, a multistakeholder programme working to improve labour conditions in the sugarcane industry and beyond. Funding was provided by the German Investment Corporation (DEG) and German Ministry for Economic Development and Cooperation (BMZ) and the Ingenio San Antonio (ISA) sugar mill via the DEG and BMZ’s DeveloPPP.de Programme. Under the programme, the DEG and BMZ fund half of the programme and the loan recipient, ISA in this case, the other half. The half funded by DEG and BMZ is dedicated to the Adelante programme, the half funded by ISA is dedicated to a programme of direct aid for those already sick. The only exception is US$150 000 per year the mill puts towards the logistical costs associated with Adelante. They do not pay for the research, or researchers, and do not have any input on lines of inquiry or their reporting. Laboratory analyses were paid directly to Department of Clinical Chemistry, Skåne University Hospital in Lund, Sweden by ISA from the matching funds designated by the DeveloPPP.de programme. Due to the structure of the DeveloPPP.de programme, funds do have to pass through the sugar mill briefly (for about 24 hours) and are then passed to the non-governmental organisation, La Isla Network, to pay for the management and execution of the research. Gothenburg and Lund Universities also supported the work by inkind funding. Stavros Niarchos Foundation provided funds directly to La Isla Network for management and execution of the research ahead of and during harvest 1.
Competing interests UE and JA declare that their institution was paid directly by ISA for laboratory analyses from the matching funds designated by the DeveloPPP.de programme.
Patient consent for publication Not required.
Ethics approval This study was approved by the Comité de Ética para Investigaciones Biomédicas (CEIB), Facultad de Ciencias Médicas, Universidad Nacional Autónoma de Nicaragua (UNAN- León), FWA000045231/IRB00003342. The biochemical investigation carried out at the Division of Clinical Chemistry and Pharmacology at Lund University in Sweden was approved by the Regional Ethical Review Board in Lund (reg. no. 2018–256). Our trained staff apprised all workers of the study objectives and procedures and answered any questions before participants signed an informed consent after which they were interviewed by our staff and provided serum samples taken by ISA phlebotomists.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement No data are available.