Absence of conflict of interest.
Citation
Highlights
- The study's objective was to examine the impact of cooling interventions on agricultural workers’ health and safety.
- The study was a randomized controlled trial that assigned workers to one of three treatment groups (cooling bandana, cooling vest, or both) or the control group. Using data from biometrics equipment and surveys, the author conducted statistical models to compare outcomes between the groups.
- The study authors did not find statistically significant relationships between the cooling interventions and heat measurements for the participants.
- This study receives a moderate evidence rating. This means we are somewhat confident that any estimated effects would be attributable to the cooling interventions, but other factors might also have contributed. However, the study did not find statistically significant effects.
Features of the Intervention
Agricultural workers spend their time outdoors in direct sunlight and in humid conditions, which puts them at a high risk for heat-related illnesses. In this study, the author examined how three types of cooling gear affect workers: cooling bandanas, cooling vests, and a combination of both. To use cooling bandanas, participants soaked the bandana in water for one minute to activate it, squeezed out the extra water, and tied it around their head or neck. They wore it for four hours and repeated the process to keep it cool. For the cooling vests, participants received cooling inserts that fit into the vest and stayed at 58 degrees Fahrenheit for three to five hours. They were provided with an additional set of frozen inserts to replace the initial ones once they had melted. Participants who were given both the cooling bandana and cooling vest completed the steps for each method.
Features of the Study
The study was a randomized controlled trial that assigned agricultural workers to one of the three intervention groups or the control group. The sample was selected from agriculture sites in Homestead and Pearson, Florida. Eligible participants had to be between the ages of 18 and 54, have worked in agriculture for at least the past four weeks, and could not be pregnant or have type I diabetes. Of the 84 eligible participants, 22 were assigned to the cooling bandana group, 21 were assigned to the cooling vest group, 21 were assigned to the group using both the bandana and vest, and 20 were assigned to the control group. Workers in the three intervention groups wore their cooling gear while working, while those in the control group did not use any cooling gear during the workday. The study sample included mostly women (66%) with an average age of 42 years. Most participants were immigrants from Mexico (79%). The groups were similar in terms of body mass index and their history of hypertension and type 2 diabetes.
The primary data sources were biometric data recorders that participants wore on their waists and surveys completed after work about their heat-related illness symptoms. The data recorders gathered information from temperature sensors that participants ingested before starting their workday. Their core body temperature was measured every 30 seconds during the day. The author used statistical models to compare the outcomes of treatment and control group members.
Findings
Health and safety
The study found no significant differences in the proportion of participants with a body temperature over 38 degrees Celsius or in heat-related illnesses between the intervention groups (cooling bandana, cooling vest, or bandana and vest) and the control group.
Considerations for Interpreting the Findings
The author noted that technical problems led to the loss of core temperature data, resulting in a smaller sample size for the analysis leading to high attrition. However, the author accounted for preexisting differences between the groups before program participation. Therefore, the study is eligible for a moderate evidence rating
Causal Evidence Rating
This study receives a moderate evidence rating because it was based on a randomized controlled trial with high attrition, but the authors ensured that the groups being compared were similar before the intervention. This means we are somewhat confident that any estimated effects would be attributable to the cooling interventions, but other factors might also have contributed. However, the study did not find any statistically significant effects.