Background: With increasing trends of rising temperatures and extreme weather events, agricultural worker populations are at an increased risk for heat-related illness (HRI). A few studies utilizing survey methods have examined the predictive factors of HRI development in farmworker populations, but studies to examine the feasibility of field-based biomonitoring of heat-related illness in farmworker populations are needed.
Purpose: The purpose of this dissertation was to develop a guiding framework conceptualizing farmworker vulnerability to heat, assess the feasibility of field-based biomonitoring of HRI in a sample of farmworkers and characterize the heat stress response.
Sample and Design: This was a feasibility study utilizing a repeated measures design guided by the Farmworker Vulnerability to Heat Hazards Framework. Forty-three male and female fernery workers participated in a biomonitoring protocol over 3 workdays following an initial baseline visit. The biomonitoring protocol included continuous core temperature, heart rate, actigraphy monitoring over the course of the workday as well as dehydration assessment before and after the workday. Self-reported HRI symptoms were also recorded, along with body composition measurements. Analyses included means, descriptive plots, and a logistic regression utilizing a generalized estimating equations approach to predict the key outcome variable of whether a participant's body core temperature (Tc) exceeded 38.0ºC (100.4ºF).
Results: Core temperature data was captured for two study days in nearly 90% of study participants. An improved protocol for core temperature monitoring was developed and best methods for future studies were identified. Participant Tc exceeded 38.0ºC on forty-nine (57%) of the workdays examined (n=86). On average, for those who met or exceeded 38.0ºC (100.4ºF), the duration of time was 79 minutes (SD=73, range=255). Energy expenditure was found to be a significant predictor (OR=1.08 [1.005,1.15]) for the key outcome variable and once adjusting for energy expenditure being female was also a significant predictor (OR=5.37, CI.95[1.03,18.30]).
Conclusion: The Farmworker Vulnerability to Heat Hazards Framework provides a base for designing studies regarding HRI in farmworkers. Field-based biomonitoring is indeed feasible and findings should be utilized to guide the design and implementation of future studies.
Table of Contents
Statement of the Problem 1
Specific Aims 3
Conceptual Framework 4
Relevance of the Study 6
Defining Heat-Related Illness 6
Fernery Operations 8
Heat-Related Illness in Farmworkers 8
Vulnerability of Farmworkers 13
Paper 1: Farmworker Vulnerability to Heat Hazards: A Conceptual Framework 21
Paper 2: Heat Exposure in Central Florida Fernery Workers: Results of a Feasibility Study 42
Paper 3: Elevated Core Temperature in Florida Fernery Workers: Results of a Pilot Study 68
Integrative Summary and Synthesis 86
Key Contributions 86
Conceptual Framework Synthesis 86
Vulnerability Factors 87
Workplace Exposure 87
Adaptive Capacity 87
Heat Stress Response 89
Feasibility and Best Methods 89
Recruitment, Population, and Setting 89
Environmental Temperature Monitoring 90
Core Temperature Monitoring 91
Energy Expenditure Monitoring 92
Dehydration Assessment 92
Body Composition Assessment 93
Heat Stress Response Assessment 93
Evidence of Heat Stress Response in Florida Fernery Workers 95
Future Directions 96
Protocol Improvements 96
About this Dissertation
|Committee Chair / Thesis Advisor|
|Characterizing Heat-Related Illness in Florida Farmworkers: A Feasibility Study ()||2018-08-28 12:30:54 -0400||