There is no conflict of interest.
Citation
Chicas, R., Xiuhtecutli, N., Elon, L., Scammell, M. K., Steenland, K., Hertzberg, V., & McCauley, L. (2021). Cooling interventions among agricultural workers: A pilot study. Workplace Health & Safety, 69(7), 315–322. https://doi.org/10.1177/2165079920976524
Highlights
- The study's objective was to examine the impact of cooling technologies on agricultural workers’ health and safety.
- The study was a randomized controlled trial that assigned workers to one of three treatment groups or the control group. Using data from biometrics equipment and surveys, the author conducted statistical models to compare the outcomes of treatment and control group members.
- The study did not find any significant effects of the cooling technologies on either elevated core body temperature or self-reported heat-related illness symptoms.
- This study receives a low evidence rating. This means we are not confident that any estimated effects would be attributable to the use of cooling technologies; other factors are likely to have contributed. However, the study did not find statistically significant effects.
Intervention Examined
Cooling Technologies
Features of the Study
The study used a randomized controlled trial to examine the effectiveness of different cooling technologies on heat-related illness symptoms and elevated core body temperatures. The intervention targeted agricultural workers in Homestead and Pearson, Florida. The study included 84 agricultural workers assigned to a control group or one of three treatment groups using different cooling technologies. A total of 78 workers completed the workday trial, with 20 in the cooling bandana group, 20 in the cooling vest group, and 21 in the group using both cooling methods. The control group had 17 workers who did not use any cooling technology. Participants in the treatment groups wore their assigned cooling devices throughout the workday. The cooling bandanas were soaked in water for one minute, then worn for four hours, with participants repeating the soaking process to maintain their coolness. The cooling vests contained inserts that maintained a temperature of 58 degrees Fahrenheit for three to five hours, and participants received additional frozen inserts to replace those that melted. Those using both cooling methods followed the procedures for each device.
The study included workers aged 18 to 54, with an average age of 42, all of whom had recent agricultural experience (at least four weeks). None were pregnant or had Type 1 diabetes. About 66% were women, with an average of 17 years of agricultural experience, and working approximately 7 hours and 40 minutes daily. Work settings included fernery (42%), nursery (41%), field crop (12%), and landscape (6%). The authors monitored body temperature and physical activity using ingested biomonitoring devices. Body temperature was recorded every 30 seconds during the workday, with elevated temperature defined as two consecutive readings above 38 degrees Celsius. Participants also completed a post-workday survey reporting symptoms of heat-related illness (HRI), including excessive sweating, headache, nausea, confusion, dizziness, fainting, and muscle cramps. The authors used statistical models to compare core body temperature increases and HRI symptoms between the treatment and control groups.
Findings
- Health and safety. The study found no significant differences in elevated core body temperature or any self-reported HRI symptoms between the treatment group and control group members.
Considerations for Interpreting the Findings
Although this study was a randomized controlled trial, it had high attrition. Therefore, the authors must demonstrate that the two groups were similar before the intervention. The authors accounted for age, sex, and pre-intervention measures of outcomes but did not account for other factors that could have affected the difference between the groups, such as race/ethnicity as required by the protocol. These preexisting differences between the groups—and not the cooling technologies—could explain the observed outcomes. Therefore, the study is not eligible for a high or moderate causal evidence rating.
Causal Evidence Rating
The quality of causal evidence presented in this report is low because it was a randomized controlled trial with high attrition and the authors did not ensure that the groups being compared were similar before the intervention. This means we are not confident that any estimated effects would be attributable to the use of cooling technologies; other factors are likely to have contributed. However, the study did not find statistically significant effects.