CKDu in Sugarcane Workers in Guatemala

This protocol describes two prospective cohort studies and one intervention study that will be conducted throughout the sugarcane harvest, from October through May, at Pantaleon's sugarcane plantations in Guatemala.

Overview of Studies

The investigators propose to conduct the three studies by making use of existing pre-employment data from prior years and by collecting new data during the 6-month sugarcane harvest. Pre-employment data are collected for all workers (N=5000) by Pantaleon and screenings occur throughout the harvest. Pre-employment and screening data include information on demographics, behaviors, work practices, non-communicable diseases, including kidney disease.

The purpose of the three new studies will be to collect detailed data on risk factors and biomarkers for CKDu. Risk factors will be assessed by collecting information through surveys and medical exams, and by collecting biological samples (blood and urine) from a subsample of the workers.

Study 1) Natural History of CKDu Study

Study Rationale: This study will prospectively follow a cohort of sugarcane workers (N=407) over multiple years to understand the natural history of CKDu. By following this cohort of workers, we will be able to describe the prevalence and incidence of abnormal eGFR and identify risk factors for CKDu.

Study Design and Populations: Pantaleon conducted a post-harvest evaluation of 407 workers following the 2015-2016 harvest. The investigators will conduct a prospective longitudinal study of this established cohort of workers (recruited during the end of the 2015-16 harvest) and will work with Pantaleon to replicate this post-harvest evaluation at the end of the 2016-2017 harvest.

Study 2) Industrial Mill Worker Observational Study

Study Rationale: This study will prospectively follow a stratified random selection of 100 mill workers throughout the harvest to understand the prevalence and incidence of kidney damage. The investigators will be able to describe the prevalence and incidence of abnormal eGFR and identify risk factors for CKDu. Although mill workers are indoors, we have informally observed that some of them work under conditions of high heat, placing them at risk for heat stress, dehydration and possibly CKDu.

Study Design and Population: Occupational Health and Safety staff at Pantaleon have identified job descriptions associated with heat exposure in the mill. Pantaleon will conduct pre-employment evaluations among 100 mill workers, specifically selecting a random sample of workers with job titles associated with high heat. At the end of the harvest, the investigators will collect occupational and non-occupational risk factors through a survey and medical exam and measure creatinine levels through a blood finger prick among the 100 mill workers.

Study 3) Hydration Study

Study Rationale: This study will prospectively assess acute and chronic kidney damage among sugarcane workers by evaluating kidney function a) before the start of the harvest and at the end of the harvest, and b) before and after work shifts during the harvest. An intervention will be implemented aimed at increasing hydration and reducing heat stress among sugarcane workers throughout the day. The investigators will assess the effectiveness of this intervention in increasing hydration and work productivity, with the final goal of the intervention aimed at decreasing acute and chronic kidney damage.

Study Design and Population: This study will comprise of the following: 1) implementation of an intervention which will include a wellness incentive and enhanced education on heat stress and hydration, and 2) investigation of biological markers of dehydration and acute kidney injury among approximately 500 sugarcane workers. Workers will be recruited from 10 work groups randomly selected at the Pantaleon work site. Each group will have data collected 3 times during the 6-month harvest.

Sub-Study 3.1) Heat Sub-study

Study Rational: This sub-study will increase understanding of the physiological response of workers to heat exposure and determine the workers' metabolic workload. The investigators will be able to examine across shift changes of physiological responses and its effects on acute and chronic kidney function. It will help determine if workers are receiving sufficient duration and number of rest periods.

Study Design and Population: Among the participants of the Hydration study, 100 workers will be randomly selected to participate in the Heat study. Data for this study will be collected during 3 periods of the Hydration Study (November, January, and March). When each Heat Sub-study participant is having data collected for the Hydration Study, the investigators will collect this additional information for that participant.