Feasibility of physiologic biomontoring of occupational heat-related illness in central Florida farmworkers

Background: Heat-related illness (HRI) is a serious occupational health concern. Certain occupational groups are at an increased risk for HRI, including agricultural workers. Fernery workers are a subpopulation of agricultural workers facing intense heat and humidity at the workplace. Objectives: This pilot study will determine the feasibility of characterizing environmental and personal factors associated with heat-related illness in fernery workers. Methods: In partnership with the Farmworker Association of Florida, a consecutive convenience sample of 10 men and 10 women from a population of fernery workers working in Central Florida during the month of July. Physiologic measurements included body composition, simultaneous heart rate (HR) and intestinal core body temperature (CT), work intensity, hydration and self-reported HRI symptoms over a 3-day study period. To assess acceptability, farmworker participants also completed an exit survey. Environmental measurements of wet-bulb globe temperature (WBGT) were captured using real-time local weather network data. Results: Recruitment rates were 50% of all potential participants approached, primarily due to work availability, eligibility and transportation barriers with attrition of <10%. Baseline physiologic measurements were successfully obtained from participants. Participant exit surveys indicated high acceptability of study methods, equipment and willingness to recommend participation in similar studies to other workers. WBGTs reached a level of 73°F, a known hazardous temperature for vulnerable groups. Conclusions: This pilot provides support that physiologic monitoring in agricultural populations is not only feasible, but has the potential to advance occupational heat exposure assessment in an unprecedented way. Knowledge gained will inform the design of a larger study.