The influence of occupational heat stress on serum inflammatory cytokines among traditional bakery workers in Iran.

Heat exposure exceeding the ISO7243:1989 standard limit can contribute to health problems among employees in a variety of workplaces. Ignoring heat standard requirements in hot working conditions such as bakeries results in physiologic and health problems, as well as an elevated risk of later illnesses. In this analytical case-control study, the serum levels of four inflammatory factors (interleukin-1 beta, interleukin-6, tumor necrosis factor-α, and C-reactive protein) were assessed using an enzyme-linked immunosorbent assay. 105 male artisan bakers (in four job classifications in bakeries and staff) were compared based on demographic characteristics and inflammatory factors. The findings of the study showed correlations between serum interleukin-1ß, interleukin-6, and C-reactive protein levels and thermal exposure in the occupational environment and employment type. Moreover, some differences in serum level of interleukin-1ß and job type were observed. Heat overexposure affected the increase of interleukin-1ß and C-reactive protein secretion. As a result of years of working in high-temperature conditions, inflammation can lead to subsequent diseases in workers. To protect their health from this occupational hazard, additional safeguards are needed. Our recommendations could also be applied to overly hot work environments that may cause heat stress in workers.

Practical cooling interventions for preventing heat strain in indoor factory workers in Thailand.

BACKGROUND: Occupational heat stress, exacerbated by factors such as climate change and insufficient cooling solutions, endangers the health and productivity of workers, especially in low-resource workplaces. OBJECTIVE: To evaluate the effectiveness of two cooling strategies in reducing physiological strain and productivity of piece-rate workers over a 9-h work shift in a southern Thailand sawmill. METHODS: In a crossover randomized control trial design, 12 (33 ± 7 y; 1.58 ± 0.05 m; 51 ± 9 kg; n = 5 females) medically screened sawmill workers were randomly allocated into three groups comprising an established phase change material vest (VEST), an on-site combination cooling oasis (OASIS) (i.e., hydration, cold towels, fans, water dousing), and no cooling (CON) across 3 consecutive workdays. Physiological strain was measured via core temperature telemetry and heart rate monitoring. Productivity was determined by counting the number of pallets of wood sorted, stacked, and stowed each day. RESULTS: Relative to CON, OASIS lowered core temperature by 0.25°C [95% confidence interval = 0.24, 0.25] and heart rate by 7 bpm [6, 9] bpm, compared to 0.17°C [0.17, 0.18] and 10 [9,12] bpm reductions with VEST. It was inconclusive whether productivity was statistically lower in OASIS compared to CON (mean difference [MD] = 2.5 [-0.2, 5.2]), and was not statistically different between VEST and CON (MD = 1.4 [-1.3, 4.1]). CONCLUSIONS: Both OASIS and VEST were effective in reducing physiological strain compared to no cooling. Their effect on productivity requires further investigation, as even small differences between interventions could lead to meaningful disparities in piece-rate worker earnings over time.

Changes in wet bulb globe temperature and risk to heat-related hazards in Bangladesh.

The rise in temperatures and changes in other meteorological variables have exposed millions of people to health risks in Bangladesh, a densely populated, hot, and humid country. To better assess the threats climate change poses to human health, the wet bulb globe temperature (WBGT) is an important indicator of human heat stress. This study utilized high-resolution reanalysis data from the fifth-generation European Centre for Medium-Range Weather Forecasts (ECMWF ERA5) to analyze the spatiotemporal changes in outdoor WBGT across Bangladesh from 1979 to 2021, employing Liljegren's model. The study revealed an increase in the annual average WBGT by 0.08-0.5 °C per decade throughout the country, with a more pronounced rise in the southeast and northeast regions. Additionally, the number of days with WBGT levels associated with high and extreme risks of heat-related illnesses has shown an upward trend. Specifically, during the monsoon period (June to September), there has been an increase of 2-4 days per decade, and during the pre-monsoon period (March to May), an increase of 1-3 days per decade from 1979 to 2021. Furthermore, the results indicated that the escalation in WBGT has led to a five-fold increase in affected areas and a three-fold increase in days of high and extreme heat stress during the monsoon season in recent years compared to the earlier period. Trend and relative importance analyses of various meteorological variables demonstrated that air temperature is the primary driver behind Bangladesh's rising WBGT and related health risks, followed by specific humidity, wind speed, and solar radiation.

Melatonin administration during the first half of pregnancy improves physiological response and reproductive performance of rabbits under heat stress conditions.

Context Melatonin may have a heat-stress-alleviating role during pregnancy. Aims To investigate the effects of melatonin administration during the first half of pregnancy on heat-tolerance capacity and pregnancy outputs of naturally heat-stressed rabbits. Methods Forty female rabbits were stratified equally into two experimental groups and daily received 1mg melatonin/kg body weight or not (control) for 15 consecutive days post-insemination. Heat tolerance indices, hormone profile, ovarian structures, and fetal loss were determined. Key results Treatment with melatonin significantly decreased respiration rate and rectal temperature, improved concentrations of nitric oxide, and tended to decrease malondialdehyde concentrations (P =0.064) compared to control. Melatonin treatment significantly increased concentrations of high-density lipoprotein, oestradiol, and progesterone compared to control. No significant differences in the numbers of visible ovarian follicles, corpora lutea, and total implantation sites on day 18 of pregnancy were observed between experimental groups. However, melatonin treatment significantly reduced the number of absorbed implantation sites and significantly improved amniotic fluid volume and conception rate compared to control. Conclusions Melatonin administration during the first half of pregnancy can improve reproductive performance of heat-stressed female rabbits. Implications Melatonin can improve fetal survivability via improving heat-tolerance capacity of does and steroidogenesis.

Heat exhaustion and heat stroke among active component members of the U.S. Armed Forces, 2019-2023.

The most serious types of heat illnesses, heat exhaustion and heat stroke, are occupational hazards associated with many of the military's training and operational environments. These illnesses can typically be prevented by appropriate situational awareness, risk management strategies, along with effective countermeasures. In 2023, the crude incidence of heat stroke and heat exhaustion were 31.7 and 172.7 cases per 100,000 person-years, respectively. The rates of incident heat stroke declined during the 2019 to 2023 surveillance period, but rates of incident heat exhaustion increased over the same period. In 2023, higher rates of heat stroke were observed among male service members compared to their female counterparts, and female service members experienced higher rates of heat exhaustion compared to male personnel. Heat illness rates were also higher among those younger than age 20, Marine Corps and Army service members, non-Hispanic Black service members, and recruits. Leaders, training cadres, and supporting medical and safety personnel must inform their subordinate and supported service members of heat illness risks, preventive measures, early signs and symptoms of illness, and appropriate interventions.

Farmworker Acceptability of Backpack Hydration Systems.

OBJECTIVE: To improve water access while working and contribute to fewer heat-related illnesses (HRI), backpack hydration systems were provided to over 200 farmworkers to use during the 2022 growing season. Acceptability of the water intake intervention was assessed among farmworkers in eastern North Carolina, USA. METHODS: With a pre-established community-university partnership, the acceptability of the intervention was assessed using a cross-sectional survey. The backpack brand selected included a 3-liter water bladder and attached drinking hose. Data analysis included descriptive and correlation statistics. RESULTS: Among 47 male, migrant farmworkers, most (90%) reported the hydration backpack to be acceptable or completely acceptable to workplace fluid intake. Most (53%) reported using the backpack some of the time, compared to 28% who used it often. The participants reported an average of 4.8 (SD 2.2) liters of water intake from the backpack on a typical workday. Most reported the backpack improved the quantity and frequency of their water consumption. CONCLUSION: This study was an important first step in implementation of hydration backpack systems as an HRI-preventative intervention among farmworkers. Future interventional studies could assess the efficacy of the backpacks on health outcomes, including incidence of dehydration and symptoms of HRI.

Skin transcriptome analysis in Brangus cattle under heat stress.

Heat stress is a major factor that negatively affects animal welfare and production systems. Livestock should adapt to tropical and subtropical areas and to meet this, composite breeds have been developed. This work aimed to evaluate gene expression profiles in the skin of Brangus cattle under heat stress using a case-control design, and to correlate this with skin histological characteristics. Two groups of bulls were set using rectal temperature as a criterion to define stress conditions: stressed (N = 5) and non-stressed (N = 5) groups. Skin transcriptomics was performed and correlations between breed composition, phenotypic and skin histological traits were evaluated. Results showed 4309 differentially expressed genes (P < 0.01), 2113 downregulated and 2196 upregulated. Enrichment and ontology analyses revealed 132 GO terms and 67 pathways (P < 0.01), including thermogenesis, glycolysis, gluconeogenesis, mitochondrial activity, antioxidant and immune response, and apoptosis. The identity of the terms and pathways indicated the diversity of mechanisms directed to relieve the animals' suffering, acting from simple passive mechanisms (conduction, convection and radiation) to more complex active ones (behavioural changes, evaporation, vasodilation and wheezing). Furthermore, significant differences between phenotypic and skin histological traits and correlations between pairs of traits suggested a direction towards heat dissipation processes. In this sense, number of vessels was positively correlated with number of sweat glands (P < 0.001) and both were positively correlated with zebuine genetic content (P < 0.05 and P < 0.01, respectively), gland size was positively correlated with epidermal thickness and negatively with hair length (P < 0.05), and epidermal thickness was negatively correlated with gland-epidermis distance (P < 0.0005). These results support the notion that response to heat stress is physiologically complex, producing significant changes in the expression of genes involved in several biological pathways, while the animal's ability to face it depends greatly on their skin features.

Prevalence of occupational heat stress across the seasons and its management amongst healthcare professionals in the UK.

Occupational heat stress (OHS) is an issue in healthcare facilities (HCFs) in the United Kingdom (UK). The aims of this study were to evaluate perceived levels of OHS during two seasons and its perceived consequences on healthcare professionals (HCPs) and to assess the efficacy of heat stress management (HSM) policies. An anonymous online survey was distributed to HCPs working in HCFs in the UK. The survey returned 1014 responses (87% women). Descriptive statistics and content analysis of survey data identified that OHS in HCFs is frequently experienced throughout the year and concerned most HCPs. Over 90% perceived OHS impairs their performance and 20% reported heat-related absenteeism. Awareness of HSM policies was poor and 73% deemed them not adequate. To help reduce the financial loss and impact on staff performance, health and well-being and patient safety, it is recommended that revisions and widespread dissemination of HSM policies are made.

Thermal stress and hospital admissions for cardiorespiratory disease in Brazil.

The growing body of scientific literature underscores the intricate relationship between meteorological conditions and human health, particularly in the context of extreme temperatures. However, conventional temperature-centric approaches often fall short in capturing the complexity of thermal stress experienced by individuals. Temperature alone, as a metric, fails to encompass the entirety of the thermal stress individuals face, necessitating a more nuanced understanding. In response to this limitation, climatologists have devised thermal indices-composite measures meticulously crafted to reflect the intricate interplay of meteorological factors influencing human perception of temperature. Recognizing the inadequacy of simplistic temperature-focused methodologies, our study aims to address the multifaceted nature of thermal stress. In this study, we explored the association between thermal indices and hospital admissions for circulatory and respiratory diseases in Brazil. We used an extensive dataset spanning 11 years (2008-2018) from the Brazilian Ministry of Health, encompassing a total of 23,791,093 hospitalizations for circulatory and respiratory diseases. We considered four distinct thermal indices-Discomfort Index (DI), Net Effective Temperature (NET), Humidex (H), and Heat Index (HI). We used an extension of the two-stage design with a case time series to assess this relationship. In the first stage, we applied a distributed lag non-linear modeling framework to create a cross-basis function. We next applied quasi-Poisson regression models adjusted by time-varying confounders. In the second stage, we applied meta-analysis with random effects to estimate the national relative risk (RR). Our findings suggest robust variations among the thermal indices under examination. These variations underscore the intricate nature of associations between temperature and health, with each index capturing distinct aspects of thermal conditions. Our results indicate that extreme thermal conditions, both at the low and high ends, are associated with increased risks of hospital admissions. The diverse impact observed among different indices emphasizes the complex interplay between various meteorological factors and their specific physiological consequences. This underscores the necessity for a comprehensive comprehension of temperature metrics to guide precise public health interventions, recognizing the multifaceted nature of temperature-health relationships.

[Hot weather and health risks in the focus of the Hessian health authorities : Inspection and consultation of residential care and nursing facilities since 2004]. / Hitzeschutz im Fokus der hessischen Betreuungs- und Pflegeaufsicht : Beratung und Prüfung stationärer Einrichtungen seit dem Jahr 2004.

BACKGROUND AND AIMS: Heat extremes are associated with considerable health risks, especially for vulnerable groups. To counteract these risks, public health policy calls for protective measures to be linked to heat warnings. Such links do not generally exist in Germany, with the exception of the heat inspections and consultations carried out by the Hessian health authorities since 2004. The aims of this work were to identify the structures and processes of the Hessian heat inspections and heat consultations and to derive findings for acute response to heat in residential care and nursing facilities. METHODS: We conducted 14 qualitative, semi-structured interviews with experts from the Hessian health authorities as well as with managers of residential care and nursing facilities. The analysis of the interview protocols was carried out using content-structuring qualitative content analysis. In addition, documents from the supervisory authority were analyzed. RESULTS: Every year, up to 370 heat inspections are carried out in the approximately 2500 inpatient facilities in Hesse. They are either integrated into already planned inspections or carried out separately; they focus on preventive and acute measures. In principle, heat protection can be easily integrated into the daily routine of residential health facilities. High staff turnover and lack of resources pose challenges. DISCUSSION: Inspections and consultations on heat management raise awareness of hot weather health risks and support the establishment of preventive measures. The Hessian system is a suitable orientation for other federal states.

Association Between Acute Kidney Injury Hospital Visits and Environmental Heat Stress at a Nicaraguan Sugarcane Plantation.

BACKGROUND: Mesoamerican sugarcane cutters are at a high risk of chronic kidney disease of non-traditional origin, a disease likely linked to heat-related acute kidney injury (AKI). Studies in general populations have described a positive association between high environmental temperatures and clinically assessed kidney outcomes, but there are no studies in occupational settings. METHOD: We accessed routine records of clinically diagnosed AKI (AKI-CD) and wet bulb globe temperatures (WBGT) at a large Nicaraguan sugarcane plantation and modeled the relationship between these using negative binomial regression. A rest-shade-hydration intervention was gradually enhanced during the study period, and efforts were made to increase the referral of workers with suspected AKI to healthcare. RESULTS: Each 1°C WBGT was associated with an 18% (95% confidence interval [CI]: [4, 33%]) higher AKI-CD rate on the same day and a 14% (95% CI [-5, 37%]) higher rate over a week. AKI-CD rates and severity, and time between symptoms onset and diagnosis decreased during the study period, that is, with increasing rest-shade-hydration intervention. Symptoms and biochemical signs of systemic inflammation were common among AKI-CD cases. DISCUSSION: Occupational heat stress, resulting from heavy work in environmental heat, was associated with a higher rate of clinically diagnosed AKI in a population at risk of CKDnt. Promoting rest-shade-hydration may have contributed to reducing AKI rates during the study period. Occupational health and safety personnel have key roles to play in enforcing rest, shade, and hydration practices, referring workers with suspected AKI to healthcare as well as collecting and analyzing the data needed to support workplace heat stress interventions.

Heat-related fatalities in North Carolina 1999-2017.

OBJECTIVES: Research shows the highest rates of occupational heat-related fatalities among farm laborers and among Black and Hispanic workers in North Carolina (NC). The Hispanic population and workforce in NC have grown substantially in the past 20 years. We describe the epidemiology of heat-related fatal injuries in the general population and among workers in NC. METHODS: We reviewed North Carolina death records and records of the North Carolina Office of the Chief Medical Examiner to identify heat-related deaths (primary International Classification of Diseases, Tenth Revision diagnosis code: X30 or T67.0-T67.9) that occurred between January 1, 1999, and December 31, 2017. Decedent age, sex, race, and ethnicity were extracted from both the death certificate and the medical examiner's report as well as determinations of whether the death occurred at work. RESULTS: In NC between 1999 and 2017, there were 225 deaths from heat-related injuries, and 25 occurred at work. The rates of occupational heat-related deaths were highest among males, workers of Hispanic ethnicity, workers of Black, multiple, or unknown race, and in workers aged 55-64. The highest rate of occupational heat-related deaths occurred in the agricultural industry. CONCLUSIONS: Since the last report (2001), the number of heat-related fatalities has increased, but fewer were identified as workplace fatalities. Rates of occupational heat-related deaths are highest among Hispanic workers. NC residents identifying as Black are disproportionately burdened by heat-related fatalities in general, with a wider apparent disparity in occupational deaths.

Heat-Related Emergency Department Visits - United States, May-September 2023.

Unprecedented heat waves can affect all persons, but some are more sensitive to the effects of heat, including children and adults with underlying health conditions, pregnant women, and outdoor workers. Many regions of the United States experienced record-breaking high temperatures in 2023, with populations exposed to extremely high temperatures for prolonged periods. CDC examined emergency department (ED) visits associated with heat-related illness (HRI) from the National Syndromic Surveillance Program and compared daily HRI ED visit rates during the warm-season months (May-September) of 2023 with those during 2018-2022. In the 2023 warm-season months, daily HRI ED visit rates peaked in several regions and remained elevated for a prolonged duration. More males than females sought care in EDs for HRI, especially males aged 18-64 years. CDC issued multiple public health alerts using the Epidemic Information Exchange system to bring attention to increases in ED utilization for HRI. Deaths and illnesses associated with heat exposure are a continuing public health concern as climate change results in longer, hotter, and more frequent episodes of extreme heat. Near real-time monitoring of weather conditions and adverse health outcomes can guide public health practitioners' timing of risk communication and implementation of prevention measures associated with extreme heat.

Heat and health of occupational workers: a short summary of literature.

Globally, occupational workers suffer various health impacts due to extreme heat. In this short review, we examine the literature discussing health impacts of heat on occupational workers, and then discuss certain individual and institutional measures needed to address the problem. Though the available literature in the recent decade discusses health impacts of heat on workers as various heat-related illnesses, we found very few studies examining how occupational workers suffer from issues concerning cardiovascular health, neurological health, respiratory health, and mental health. In this regard, we highlight the need for more studies to examine how occupational workers exposed to extreme heat conditions suffer from fatal health issues like cardiovascular attack, brain stroke, and other ailments impacting vital organs of the body. Occupational workers across the world should be made aware of measures to protect themselves from extreme heat. Further, countries should develop occupational heat safety guidelines with statutory effect.

Social interactions and heat stress mitigation among elderly people in a healthy city.

BACKGROUND: Increased frequencies and duration of extreme heat events have caused severe heat stress, especially among elderly people. Despite its obvious cause and universally known preventive measures, heat stress preventive measures have not been implemented effectively at community levels. This study examined heat coping practices among elderly people and their associations with living conditions, social interactions, and community involvement. METHODS: A self-administered questionnaire was done to assess heat-coping practices to mitigate heat stress, living conditions, and interactions with family, friends, and neighbours. Participants were 3000 randomly selected elderly people aged 65 years and older living in Owariasahi, Japan, a city that applies the 2004 Healthy City Approach. A generalised linear regression model was applied with binominal distribution to examine the association between social interactions and application of heat-coping practices. Sex and ages were adjusted in the model. FINDINGS: Among the 2127 elderly people who completed the survey, 745 (35·0%) had heat stress during the summer of the survey year. The presence of heat stress was higher in male participants living alone and having less interaction with friends and neighbours; only interaction with friends and relatives showed difference in the occurrence of the heat-related illness in female participants. The use of ice packs, air conditioners, and the opening of windows or doors were associated with the presence of heat stress. The odds of not applying relevant preventive practices were higher in participants disconnected from relatives and friends (odds ratio 1·52 [95% CI 1·12-2·04]). Participants living alone and disconnected from their neighbours showed similar trends to the connection with relatives and friends but not significantly. INTERPRETATION: The findings of the study indicated that heat stress mitigative measures were underused in elderly people who are socially disconnected. Heat illness prevention programmes need to focus on outreach to the disadvantaged population. FUNDING: Japan Society for the Promotion of Science.