Intervention to reduce heat stress and improve efficiency among sugarcane workers in El Salvador: Phase 1

Abstract

Background: Chronic heat stress and dehydration from strenuous work in hot environments is considered an essential component of the epidemic of chronic kidney disease in Central America.

Objective: (1) To assess feasibility of providing an intervention modelled on OSHA's Water.Rest.Shade programme (WRS) during sugarcane cutting and (2) to prevent heat stress and dehydration without decreasing productivity.

Methods: Midway through the 6-month harvest, the intervention introduced WRS practices. A 60-person cutting group was provided water supplied in individual backpacks, mobile shaded rest areas and scheduled rest periods. Ergonomically improved machetes and efficiency strategies were also implemented. Health data (anthropometric, blood, urine, questionnaires) were collected preharvest, preintervention, mid-intervention and at the end of harvest. A subsample participated in focus group discussions. Daily wet bulb globe temperatures (WBGT) were recorded. The employer provided individual production records.

Results: Over the harvest WBGT was >26°C from 9:00 onwards reaching average maximum of 29.3±1.7°C, around 13:00. Postintervention self-reported water consumption increased 25%. Symptoms associated with heat stress and with dehydration decreased. Individual daily production increased from 5.1 to a high of 7.3 tons/person/day postintervention. This increase was greater than in other cutting groups at the company. Focus groups reported a positive perception of components of the WRS, and the new machete and cutting programmes.

Conclusions: A WRS intervention is feasible in sugarcane fields, and appears to markedly reduce the impact of the heat stress conditions for the workforce. With proper attention to work practices, production can be maintained with less impact on worker health.

Keywords: Chronic kidney disease; Dehydration; Heat Stress; Intervention; Mesoamerican nephropathy.

Figure 1

Workers in the cane field taking a break in the shade provided by the mobile canopies (note the wheels on the frame and the CamelBaks).

Figure 2

Daily distribution of hourly wet bulb globe temperature (WBGT) averages for Inland (blue) and Coastland (red) groups across the harvest. Individual days (dots) plus, hourly averages and SDs across the harvest are represented. Dashed lines indicate the Occupational Safety and Health Administration permissible heat exposure limit values.

Figure 3

Percentage of Inland workers reporting symptoms of heat stress and dehydration preintervention (January 2015) and postintervention (at the end of harvest, April 2015).