The effect of the participatory heat education and awareness tools (HEAT) intervention on agricultural worker physiological heat strain: results from a parallel, comparison, group randomized study

BACKGROUND

Farmworkers are at risk of heat-related illness (HRI). We sought to: 1) evaluate the effectiveness of farmworker Spanish/English participatory heat education and a supervisor decision-support mobile application (HEAT intervention) on physiological heat strain; and 2) describe factors associated with HRI symptoms reporting.

METHODS

We conducted a parallel, comparison group intervention study from May-September of 2019 in Central/Eastern Washington State, USA. We used convenience sampling to recruit adult outdoor farmworkers and allocated participating crews to intervention (n = 37 participants) and alternative-training comparison (n = 38 participants) groups. We measured heat strain monthly using heart rate and estimated core body temperature to compute the maximum work-shift physiological strain index (PSI_max) and assessed self-reported HRI symptoms using a weekly survey. Multivariable linear mixed effects models were used to assess associations of the HEAT intervention with PSI_max, and bivariate mixed models were used to describe factors associated with HRI symptoms reported (0, 1, 2+ symptoms), with random effects for workers.

RESULTS

We observed larger decreases in PSI_max in the intervention versus comparison group for higher work exertion levels (categorized as low, low/medium-low, and high effort), after adjustment for maximum work-shift ambient Heat Index (HI_max), but this was not statistically significant (interaction - 0.91 for high versus low/medium-low effort, t = - 1.60, p = 0.11). We observed a higher PSI_max with high versus low/medium-low effort (main effect 1.96, t = 3.81, p < 0.001) and a lower PSI_max with older age (- 0.03, t = - 2.95, p = 0.004), after covariate adjustment. There was no clear relationship between PSI_max and the number of HRI symptoms reported. Reporting more symptoms was associated with older age, higher HI_max, 10+ years agricultural work, not being an H-2A guest worker, and walking > 3 min to get to the toilet at work.

CONCLUSIONS

Effort level should be addressed in heat management plans, for example through work/rest cycles, rotation, and pacing, in addition to education and other factors that influence heat stress. Both symptoms and indicators of physiological heat strain should be monitored, if possible, during periods of high heat stress to increase the sensitivity of early HRI detection and prevention. Structural barriers to HRI prevention must also be addressed.

TRIAL REGISTRATION

ClinicalTrials.gov Registration Number: NCT04234802 , date first posted 21/01/2020.

Accuracy of an estimated core temperature algorithm for agricultural workers

There is a substantial burden of occupational health effects from heat exposure. We sought to assess the accuracy of estimated core body temperature (CBT_est) derived from an algorithm that uses sequential heart rate and initializing CBT,¹ compared with gastrointestinal temperature measured using more invasive ingestible sensors (CBT_gi), among outdoor agricultural workers. We analyzed CBT_est and CBT_gi data from Washington State, USA, pear and apple harvesters collected across one work shift in 2015 (13,413 observations, 35 participants) using Bland Altman methods. The mean (standard deviation, range) CBT_gi was 37.7 (0.4, 36.5-39.4)°C. Overall CBT bias (limits of agreement) was -0.14 (±0.76)°C. Biases ranged from -0.006 to -0.75 °C. The algorithm, which does not require the use of ingestible sensors, may be a practical tool in research among groups of workers for evaluating the effectiveness of interventions to prevent adverse occupational heat health effects.

The multi-level heat education and awareness tools [HEAT] intervention study for farmworkers: Rationale and methods

Background

The burden of adverse health effects from heat exposure is substantial, and outdoor workers who perform heavy physical work are at high risk. Though heat prevention interventions have been developed, studies have not yet systematically evaluated the effectiveness of approaches that address risk factors at multiple levels.

Objective

We sought to test the effectiveness of a multi-level heat prevention approach (heat education and awareness tools [HEAT]), which includes participatory training for outdoor agricultural workers that addresses individual and community factors and a heat awareness mobile application for agricultural supervisors that supports decisions about workplace heat prevention, in the Northwest United States.

Design

We designed the HEAT study as a parallel, comparison, randomized group intervention study that recruited workers and supervisors from agricultural workplaces. In intervention arm crews, workers received HEAT training, and supervisors received the HEAT awareness application. In comparison arm crews, workers were offered non-HEAT training. Primary outcomes were worker physiological heat strain and heat-related illness (HRI) symptoms. In both worker groups, we assessed HRI symptoms approximately weekly, and heat strain physiological monitoring was conducted at worksites approximately monthly, from June through August.

Discussion

To our knowledge, this is the first study to evaluate the effectiveness of a multi-level heat prevention intervention on physiological heat strain and HRI symptoms for outdoor agricultural workers.

Trial registration

ClinicalTrials.gov Registration Number: NCT04234802;

Warming from tropical deforestation reduces worker productivity in rural communities

The accelerating loss of tropical forests in the 21st century has eliminated cooling services provided by trees in low latitude countries. Cooling services can protect rural communities and outdoor workers with little adaptive capacity from adverse heat exposure, which is expected to increase with climate change. Yet little is still known about whether cooling services can mitigate negative impacts of heat on labor productivity among rural outdoor workers. Through a field experiment in Indonesia, we show that worker productivity was 8.22% lower in deforested relative to forested settings, where wet bulb globe temperatures were, on average, 2.84 °C higher in deforested settings. We demonstrate that productivity losses are driven by behavioral adaptations in the form of increased number of work breaks, and provide evidence that suggests breaks are in part driven by awareness of heat effects on work. Our results indicate that the cooling services from forests have the potential for increasing resilience and adaptive capacity to local warming.

It is expected that tropical deforestation and related increases in heat exposure have negative impacts on labour productivity, but the size of the effect is not well known. Here, the authors show that deforestation reduces productivity by 8.22% in rural Indonesia and causes behavioural adaptation responses like more work breaks.

Association between work in deforested, compared to forested, areas and human heat strain: An experimental study in a rural tropical environment

BACKGROUND

With climate change, adverse human health effects caused by heat exposure are of increasing public health concern. Forests provide beneficial ecosystem services for human health, including local cooling. Few studies have assessed the relationship between deforestation and heat-related health effects in tropical, rural populations. We sought to determine whether deforested compared to forested landscapes are associated with increased physiological heat strain in a rural, tropical environment.

METHODS

We analyzed data from 363 healthy adult participants from ten villages who participated in a two-by-two factorial, randomized study in East Kalimantan, Indonesia from 10/1/17 to 11/6/17. Using simple randomization, field staff allocated participants equally to different conditions to conduct a 90-minute outdoor activity, representative of typical work. Core body temperature was estimated at each minute during the activity using a validated algorithm from baseline oral temperatures and sequential heart rate data, measured using chest band monitors. We used linear regression models, clustered by village and with a sandwich variance estimator, to assess the association between deforested versus forested conditions and the number of minutes each participant spent above an estimated core body temperature threshold of 38.5°C.

RESULTS

Compared to those in the forested condition (n=172), participants in the deforested condition (n=159) spent an average of 3.08 (95% CI 0.57, 5.60) additional minutes with an estimated core body temperature exceeding 38.5°C, after adjustment for age, sex, body mass index, and experiment start time, with a larger difference among those who began the experiment after 12 noon (5.17 [95% CI 2.20, 8.15]).

CONCLUSIONS

In this experimental study in a tropical, rural setting, activity in a deforested versus a forested setting was associated with increased objectively measured heat strain. Longer durations of hyperthermia can increase the risk of serious health outcomes. Land use decisions should consider the implications of deforestation on local heat exposure and health as well as on forest services, including carbon storage functions that impact climate change mitigation.

Associations between heat exposure, vigilance, and balance performance in summer tree fruit harvesters

BACKGROUND

We sought to evaluate potential mediators of the relationship between heat exposure and traumatic injuries in outdoor agricultural workers.

METHODS

Linear mixed models were used to estimate associations between maximum work-shift Wet Bulb Globe Temperature (WBGT_max) and post-shift vigilance (reaction time) and postural sway (total path length) in a cross-sectional sample of 46 Washington State tree fruit harvesters in August-September 2015.

RESULTS

The mean (SD) WBGT_max was 27.4 (3.2)°C in August and 21.2 (2.0)°C in September. The mean pre-work-shift participant urine specific gravity indicated minimal dehydration. Twenty-four percent of participants exhibited possible excessive sleepiness. There was no association between WBGT_max and post-shift reaction time or total path length.

CONCLUSIONS

Heat exposure was not associated with impaired vigilance or balance in this study, in which the overall mean (SD) WBGT_max was 25.9 (4.2)°C. However, the study identified opportunities to ensure adequate pre-work-shift hydration and to optimize sleep and work-shift timing in order to reduce occupational injury and heat-related illness risk.

Heat exposure and productivity in orchards: Implications for climate change research

Recent studies suggest that heat exposure degrades work productivity, but such studies have not considered individual- and workplace-level factors. Forty-six tree-fruit harvesters (98% Latino/a) from 6 orchards participated in a cross-sectional study in central/eastern Washington in 2015. The association between maximum measured work-shift wet-bulb globe temperature (WBGT_max) and productivity (total weight of fruit bins collected per time worked) was estimated using linear mixed-effects models, adjusting for relevant confounders. The mean (standard deviation) WBGT_max was 27.9°C (3.6°C) in August and 21.2°C (2.0°C) in September. There was a trend of decreasing productivity with increasing WBGT_max, but this association was not statistically significant. When individual- and workplace-level factors were included in the model, the association approached the null. Not considering individual, work, and economic factors that affect rest and recovery in projections of the effects of climate change could result in overestimates of reductions in future productivity and underestimate risk of heat illness.

Hydration and Cooling Practices Among Farmworkers in Oregon and Washington

OBJECTIVES

Although recommendations for preventing occupational heat-related illness among farmworkers include hydration and cooling practices, the extent to which these recommendations are universally practiced is unknown. The objective of this analysis was to compare hydration and cooling practices between farmworkers in Oregon and Washington.

METHODS

A survey was administered to a purposive sample of Oregon and Washington farmworkers. Data collected included demographics, work history and current work practices, hydration practices, access and use of cooling measures, and headwear and clothing worn.

RESULTS

Oregon farmworkers were more likely than those in Washington to consume beverages containing sugar and/or caffeine. Workers in Oregon more frequently reported using various cooling measures compared with workers in Washington. Availability of cooling measures also varied between the two states.

CONCLUSIONS

These results highlight the large variability between workers in two states regarding access to and use of methods to stay cool while working in the heat.

Risk Factors for Heat-Related Illness in Washington Crop Workers

Crop workers are at high risk of heat-related illness (HRI) from internal heat generated by heavy physical work, particularly when laboring in hot and humid conditions. The aim of this study was to identify risk factors for HRI symptoms in Washington crop workers using an audio computer-assisted self-interview (A-CASI) instrument that has undergone reliability and validity evaluation. A cross-sectional A-CASI survey of 97 crop workers in Washington State was conducted during the summer of 2013. Potential HRI risk factors in demographic, training, work, hydration, clothing, health, and environmental domains were selected a priori for evaluation. Mixed-effects logistic regression was used to identify risk factors for self-reported symptoms associated with heat strain and HRI (dizziness/light-headedness or heavy sweating) experienced at work in hot conditions. An increase in age was associated with a lower odds of HRI symptoms (odds ratio [OR] = 0.92; 95% confidence interval [CI] = 0.87-0.98). Piece rate compared with hourly payment (OR = 6.20; 95% CI = 1.11-34.54) and needing to walk for more than 3 minutes to get to the toilet, compared with less than 3 minutes (OR = 4.86; 95% CI = 1.18-20.06), were associated with a higher odds of HRI symptoms. In this descriptive study of risk factors for HRI symptoms in Washington crop workers, decreased age (and less work experience), piece rate pay, and longer distance to the toilet were associated with self-reported HRI symptoms. Modifiable workplace factors should be considered in HRI prevention efforts that are evaluated using objective measures in representative working populations.

Heat-related illness in Washington State agriculture and forestry sectors

BACKGROUND

We sought to describe heat-related illness (HRI) in agriculture and forestry workers in Washington State.

METHODS

Demographic and clinical Washington State Fund workers' compensation agriculture and forestry HRI claims data (1995-2009) and Washington Agriculture Heat Rule citations (2009-2012) were accessed and described. Maximum daily temperature (Tmax) and Heat Index (HImax) were estimated by claim date and location using AgWeatherNet's weather station network.

RESULTS

There were 84 Washington State Fund agriculture and forestry HRI claims and 60 Heat Rule citations during the study period. HRI claims and citations were most common in crop production and support subsectors. The mean Tmax (HImax) was 95°F (99°F) for outdoor HRI claims. Potential HRI risk factors and HRI-related injuries were documented for some claims.

CONCLUSIONS

Agriculture and forestry HRI cases are characterized by potential work-related, environmental, and personal risk factors. Further work is needed to elucidate the relationship between heat exposure and occupational injuries.

Assessing Hmong farmers' safety and health

This pilot project investigated agricultural-related safety and health issues among Hmong refugees working on family-operated farms. Novel approaches, namely participatory rural appraisal and photovoice, were used to conduct a qualitative occupational hazard assessment with a group of Hmong farmers in Washington State. These two methods were useful in gathering participants' own perspectives about priority concerns. Several identified problems were related to musculoskeletal disorders, handling and operating heavy machinery, heat and cold stress, respiratory exposures, pest management, and socioeconomic and language concerns. Findings from this study provide insight into the work-related challenges that Hmong refugee farmers encounter and can serve as a basis for occupational health professionals to develop interventions to assist this underserved group.

Safety and health hazard observations in Hmong farming operations

Agricultural workers have a high risk of occupational injuries, illnesses, and fatalities. However, there are very few standardized tools available to assess safety and health in agricultural operations. Additionally, there are a number of groups of agricultural workers, including Hmong refugees and immigrants, for which virtually no information on safety and health conditions is available. This study developed an observation-based methodology for systematically evaluating occupational health and safety hazards in agriculture, and pilot-tested this on several small-scale Hmong farming operations. Each observation assessed of range of safety and health hazards (e.g., musculoskeletal hazards, dust and pollen, noise, and mechanical hazards), as well as on factors such as type of work area, presence of personal protective equipment, and weather conditions. Thirty-six observations were collected on nine farms. The most common hazards observed were bending at the back and lifting <50 pounds. Use of sharp tools without adequate guarding mechanisms, awkward postures, repetitive hand motions, and lifting >50 pounds were also common. The farming activities observed involved almost no power equipment, and no pesticide or chemical handling was observed. The use of personal protective equipment was uncommon. The results of this assessment agreed well with a parallel study of perceived safety and health hazards among Hmong agricultural workers. This study suggests that small-scale Hmong farming operations involve a variety of hazards, and that occupational health interventions may be warranted in this community. The study also demonstrates the utility of standardized assessment tools and mixed-method approaches to hazard evaluation.

Identification of barriers to the prevention and treatment of heat-related illness in Latino farmworkers using activity-oriented, participatory rural appraisal focus group methods

BACKGROUND

Heat-related illness (HRI) is an important cause of non-fatal illness and death in farmworkers. We sought to identify potential barriers to HRI prevention and treatment in Latino farmworkers.

METHODS

We conducted three semi-structured focus group discussions with 35 Latino farmworkers in the Central Washington, USA area using participatory rural appraisal techniques. Interviews were audio taped and transcribed in Spanish. Three researchers reviewed and coded transcripts and field notes, and investigator triangulation was used to identify relevant themes and quotes.

RESULTS

Although the majority of participants in our study reported never receiving formal HRI training, most participants were aware that extreme heat can cause illness and were able to accurately describe HRI symptoms, risk factors, and certain prevention strategies. Four main observations regarding farmworkers' HRI-relevant beliefs and attitudes were identified: 1) farmworkers subscribe to varying degrees to the belief that cooling treatments should be avoided after heat exposure, with some believing that such treatments should be avoided after heat exposure, and others encouraging the use of such treatments; 2) the desire to lose weight may be reflected in behaviors that promote increased sweating; 3) highly caffeinated energy drinks are preferred to increase work efficiency and maintain alertness; and 4) the location of drinking water at work (e.g. next to restrooms) and whether water is clean, but not necessarily chemically-treated, are important considerations in deciding whether to drink the water provided at worksites.

CONCLUSIONS

We identified potential barriers to HRI prevention and treatment related to hydration, certain HRI treatments, clothing use, and the desire to lose weight among Latino farmworkers. Strategies to address potential barriers to HRI prevention and treatment in this population may include engineering, administrative, and health education and health promotion strategies at individual, workplace, community, and societal levels. Although farmworkers in our study were able to describe HRI risk factors, reported practices were not necessarily consistent with reported knowledge. Further study of potential knowledge-behavior gaps may uncover opportunities for additional HRI prevention strategies. Farmworkers and employers should be included in the development and evaluation of interventions to prevent HRI.

The synergy of health promotion practice/research/education

Many nurses are concerned about the lack of connection among nursing practice, research and education. However, the assumption that nursing practice, research, and education represent separate domains or activities that need to be linked, may well contravene the relational synergy they share. This paper describes a project that sought to illustrate, and further explore, the synergistic, iterative relationship of health promoting practice/research/education. The project revealed how this synergy lives out within the daily practice of frontline practitioners and how the researched knowledge practitioners bring forth through their practice can transform care.

[Measurements of the tensile force in the halo-pelvic apparatus and in the halo-Milwaukee brace (author' transl)]

A measuring device for static and dynamic recordings of the tensile force in the halo-pelvic apparatus and in the halo-Milwaukee brace was developed. The results present a survey of the tensil forces being effective during the preoperative traction in dependence on the extension distance and the duration of the treatment. The considerable variations of the tensile force, especially the high peak values, which were recorded during the normal day-to-day routine of the patients in the ward room, lead to the conclusion, that halo-gravity or halo-femoral traction is to be preferred to traction by the halo-pelvic apparatus or by the halo-Milwaukee-brace.

[Dynamic halo-gravity traction in scoliosis (author's transl)]

First results obtained in halo-gravity traction employing a new developed traction assembly are reported.

[Ito's syndrome (incontinentia pigmenti achromians)]

Ito's syndrome is a distinct entity characterized by bilateral systematized linear depigmentations denominated by Ito as "incontinentia pigmentiachromians". The syndrome includes a variety of anomalies predominantly affecting the central nervous system, the eyes, and the muscular-skeletal-system. The patient described in this paper was a 26 year old man suffering from a sever scoliosis. This anomaly had not been mentioned in previous case reports.

THE STRUCTURE OF THE PARS INTERARTICULARIS OF THE LOWER LUMBAR VERTEBRAE AND ITS RELATION TO THE ETIOLOGY OF SPONDYLOLYSIS

1. An anatomical study of the bony structure of the pars interarticularis of the fourth and fifth lumbar vertebrae has been made in specimens from seven cadavers aged seventeen to sixty-seven.

2. Layers of cortical bone have been described antero-laterally and postero-medially which are thickest in the narrowest region of the pars.

3. In one specimen from a seventeen-year-old male, a healing fracture was found in the antero-lateral layer of cortical bone in the right neural arch of the fourth lumbar vertebra.

4. The stresses to which the pars is subject consist primarily of shear forces applied to the articular processes. The significance of these stresses to the etiology of spondylolysis is discussed.