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Background: Per- and polyfluoroalkyl substances (PFASs) are persistent chemicals that firefighters encounter. Epigenetic modifications, including DNA methylation, could serve as PFASs toxicity biomarkers. Methods: With a sample size of 197 firefighters, we quantified the serum concentrations of nine PFASs, blood leukocyte DNA methylation and epigenetic age indicators via the EPIC array. We examined the associations between PFASs with epigenetic age, site- and region-specific DNA methylation, adjusting for confounders. Results: Perfluorohexane sulfonate, perfluorooctanoate (PFOA) and the sum of branched isomers of perfluorooctane sulfonate (Sm-PFOS) were associated with accelerated epigenetic age. Branched PFOA, linear PFOS, perfluorononanoate, perfluorodecanoate and perfluoroundecanoate were associated with differentially methylated loci and regions. Conclusion: PFASs concentrations are associated with accelerated epigenetic age and locus-specific DNA methylation. The implications for PFASs toxicity merit further investigation.

OBJECTIVES We use a qualitative method to gain further insight into women firefighters' experiences, perceptions of cancer, health, and safety risks in the fire service. METHODS We conducted six focus groups with U.S. women firefighters. Participants engaged in a 60 to 75-minute, semi-structured discussion and completed a sociodemographic questionnaire. A qualitative descriptive approach was used to inductively create themes. Data collection concluded when saturation was met. RESULTS Forty-nine women firefighters participated. Qualitative results indicated the main health concerns include: occupational cancer risks including, risks related to hazardous exposures, sleep disruption and stress; and women's health concerns including, cancer, pregnancy and breastfeeding, and lack of resources. CONCLUSIONS Women firefighters are concerned about their risk for cancer due to their occupation and identify a lack of resources specific to health and safety needs of women firefighters.

BACKGROUND: Firefighters have occupational and environmental exposures to per- and polyfluoroalkyl substances (PFAS). The goal of this study was to compare serum PFAS concentrations across multiple United States fire departments to National Health and Nutrition Examination Survey (NHANES) participants. METHODS: Nine serum PFAS were compared in 290 firefighters from four municipal fire departments (coded A–D) and three NHANES participants matched to each firefighter on sex, ethnicity, age, and PFAS collection year. Only Departments A and C had sufficient women study participants (25 and six, respectively) to compare with NHANES. RESULTS: In male firefighters compared with NHANES, geometric mean perfluorohexane sulfonate (PFHxS) was elevated in Departments A–C, sum of branched perfluoromethylheptane sulfonate isomers (Sm-PFOS) was elevated in all four departments, linear perfluorooctane sulfonate (n-PFOS) was elevated in Departments B and C, linear perfluorooctanoate (n-PFOA) was elevated in Departments B–D, and perfluorononanoate (PFNA) was elevated in Departments B–D, but lower in A. In male firefighters compared with NHANES, perfluoroundecanoate (PFUnDA) was more frequently detected in Departments B and D, and 2-(N-methyl-perfluorooctane sulfonamido) acetate (MeFOSAA) was less frequently detected in Departments B–D. In female firefighters compared with NHANES, PFHxS and Sm-PFOS concentrations were elevated in Departments A and C. Other PFAS concentrations were elevated and/or reduced in only one department or not significantly different from NHANES in any department. CONCLUSIONS: Serum PFHxS, Sm-PFOS, n-PFOS, n-PFOA, and PFNA concentrations were increased in at least two of four fire departments in comparison to NHANES.

PURPOSE OF REVIEW: The burden of heat-related adverse occupational health effects, as well as traumatic injuries, is already substantial. Projected increases in mean temperatures and extreme events may increase the risk of adverse heat health effects and enhance disparities among exposed workers. This article reviews the emerging literature on the relationship between heat exposure and occupational traumatic injuries and discusses implications of this work. RECENT FINDINGS: A recent meta-analysis of three case-crossover and five time-series studies in industrialized settings reported an association of increasing occupational injuries with increasing heat exposure, with increased effect estimates for male gender and age less than 25 years, although heterogeneity in exposure metrics and sources of bias were demonstrated to varying degrees across studies. A subsequent case-crossover study in outdoor construction workers reported a 0.5% increase in the odds of traumatic injuries per one °C increase in maximum daily humidex (odds ratio 1.005 [95% CI 1.003–1.007]). While some studies have demonstrated reversed u-shaped associations between heat exposure and occupational injuries, different risk profiles have been reported in different industries and settings. SUMMARY: Studies conducted primarily in industrialized settings suggest an increased risk of traumatic injury with increasing heat exposure, though the exact mechanisms of heat exposure’s effects on traumatic injuries are still under investigation. The effectiveness of heat-related injury prevention approaches has not yet been established. To enhance the effectiveness of prevention efforts, prioritization of approaches should not only take into account the hierarchy of controls, social-ecological models, community and stakeholder participation, and tailoring of approaches to specific local work settings, but also methods that reduce local and global disparities and better address the source of heat exposure, including conservation informed land-use planning, built environment, and prevention through design approaches. Participation of occupational health experts in transdisciplinary development and integration of these approaches is needed.

OBJECTIVES: The primary objective of this study was to assess the relationship between heat exposure and occupational traumatic injuries among construction workers. METHODS: We assessed the relationship between humidex, a measure of apparent temperature, and Washington State Fund workers’ compensation injuries among outdoor construction workers using a case-crossover design with time-stratified referent selection. Warm month (March–October) adult outdoor construction traumatic injury claims from 2000–2012 were spatiotemporally joined with high-resolution meteorological data. We used conditional logistic regression with linear splines to assess the association between maximum daily humidex and injuries. RESULTS: There were 63 720 occupational traumatic injury claims in construction that met our eligibility criteria during the study period. The traumatic injury odds ratio (OR) was 1.005 [95% confidence interval (CI) 1.003–1.007] per one °C change in humidex. In the spline analyses, we observed a nearly linear association of humidex with the risk of a traumatic injury. Effect estimates were higher among younger (18–24 years) and older (>54 years) workers, workers with lower extremity injuries, workers with less job experience, smaller employers, workers working in Western Washington, and time of injury before 12:30 hours, although CI of effect estimates overlapped in stratified analysis categories. CONCLUSIONS: In this study of Washington outdoor construction workers, increasing maximum daily humidex was associated with increasing traumatic injury risk. Further work should explore mechanisms of the association between heat exposure and traumatic injuries. Injury prevention efforts targeted at construction should address heat-related risk factors. In addition, heat awareness campaigns should address outcomes beyond heat-related illness.

Firefighters are exposed to a variety of environmental hazards and are at increased risk for multiple cancers. There is evidence that risks differ by ethnicity, yet the biological or environmental differences underlying these differences are not known. DNA methylation is one type of epigenetic regulation that is altered in cancers. In this pilot study, we profiled DNA methylation with the Infinium MethylationEPIC in blood leukocytes from 31 Hispanic white and 163 non-Hispanic white firefighters. We compared DNA methylation (1) at 12 xenobiotic metabolizing genes and (2) at all loci on the array (>740 000), adjusting for confounders. Five of the xenobiotic metabolizing genes were differentially methylated at a raw P-value

Objectives: The primary objective of this study was to assess the relationship between heat exposure and occupational injuries in construction workers.Methods: The relationship between maximum dail...

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.

Background: Environmental heat exposure is a public health concern. The impacts of environmental heat on mortality and morbidity at the population scale are well documented, but little is known abo...

Background Recent research suggests that heat exposure may increase the risk of traumatic injuries. Published heat-related epidemiological studies have relied upon exposure data from individual weather stations. Objective To evaluate the association between heat exposure and traumatic injuries in outdoor agricultural workers exposed to ambient heat and internal heat generated by physical activity using modeled ambient exposure data. Methods A case-crossover study using time-stratified referent selection among 12,213 outdoor agricultural workers with new Washington State Fund workers’ compensation traumatic injury claims between 2000 and 2012 was conducted. Maximum daily Humidex exposures, derived from modeled meteorological data, were assigned to latitudes and longitudes of injury locations on injury and referent dates. Conditional logistic regression was used to estimate odds ratios of injury for a priori daily maximum Humidex categories. Results The mean of within-stratum (injury day and corresponding referent days) standard deviations of daily maximum Humidex was 4.8. The traumatic injury odds ratio was 1.14 (95% confidence interval 1.06, 1.22), 1.15 (95% confidence interval 1.06, 1.25), and 1.10 (95% confidence interval 1.01, 1.20) for daily maximum Humidex of 25–29, 30–33, and ≥34, respectively, compared to < 25, adjusted for self-reported duration of employment. Stronger associations were observed during cherry harvest duties in the June and July time period, compared to all duties over the entire study period. Conclusions Agricultural workers laboring in warm conditions are at risk for heat-related traumatic injuries. Combined heat-related illness and injury prevention efforts should be considered in high-risk populations exposed to warm ambient conditions in the setting of physical exertion.

Outdoor workers performing heavy physical labour in hot conditions are at increased risk for developing occupational heat-related illness. Seasonal harvesting of certain tree fruits in Washington occurs during summer months. In addition to environmental heat exposure, harvesting involves internal heat generation from physical work. We sought to characterise heat stress and physiological effects of heat stress (heat strain) in workers performing harvest activities. During the summer of 2015, 46 pear and apple harvesters participated in a cross-sectional study in Yakima Valley, Washington for one work shift during warmer periods in August (n = 34) and cooler periods in September (n = 12). Heat stress and strain were characterised using American Conference of Governmental Hygienist (ACGIH) guidelines, which recommend thermal Action Limits and Threshold Limit Values based on several factors including: environmental temperatures, metabolic rate of task, clothing ensembles, core body temperature, and heart rate. Heat exposure was measured near individual workers using hand-held Wet Bulb Globe Temperature (WBGT) monitors, metabolic rate was estimated using field observations and hip-mounted accelerometers, and research staff observed workers’ clothing. Heart rate and core body temperature were monitored using heart rate monitors and ingestible core body temperature sensors. Of the 46 participants, 25 (54.4%) exceeded the ACGIH Action Limit (WBGT 25°C), and 16 (34.8%) exceeded the Threshold Limit Value (WBGT 28°C) for a moderate work task (300 Watts). All participants exceeding the Threshold Limit Value were working in August. Using accelerometer data (n = 39), 12 (30.8%) exceeded the Action Limit and 4 (10.3%) exceeded the Threshold Limit Value. Heat strain data are currently being analysed. Under current conditions, workers are exposed to hazardous thermal environments. Future climate conditions may further impact physically intensive outdoor occupations. Effective approaches for reducing heat exposure and/or promoting biological adaptation to heat are needed to prevent heat-related illness in vulnerable working populations.

Background Exposure to excessive heat kills more people than any other weather-related phenomenon, aggravates chronic diseases, and causes direct heat illness. Strong associations between extreme heat and health have been identified through increased mortality and hospitalizations and there is growing evidence demonstrating increased emergency department visits and demand for emergency medical services (EMS). The purpose of this study is to build on an existing regional assessment of mortality and hospitalizations by analyzing EMS demand associated with extreme heat, using calls as a health metric, in King County, Washington (WA), for a 6-year period. Methods Relative-risk and time series analyses were used to characterize the association between heat and EMS calls for May 1 through September 30 of each year for 2007–2012. Two EMS categories, basic life support (BLS) and advanced life support (ALS), were analyzed for the effects of heat on health outcomes and transportation volume, stratified by age. Extreme heat was model-derived as the 95th (29.7 °C) and 99th (36.7 °C) percentile of average county-wide maximum daily humidex for BLS and ALS calls respectively. Results Relative-risk analyses revealed an 8 % (95 % CI: 6–9 %) increase in BLS calls, and a 14 % (95 % CI: 9–20 %) increase in ALS calls, on a heat day (29.7 and 36.7 °C humidex, respectively) versus a non-heat day for all ages, all causes. Time series analyses found a 6.6 % increase in BLS calls, and a 3.8 % increase in ALS calls, per unit-humidex increase above the optimum threshold, 40.7 and 39.7 °C humidex respectively. Increases in “no” and “any” transportation were found in both relative risk and time series analyses. Analysis by age category identified significant results for all age groups, with the 15–44 and 45–64 year old age groups showing some of the highest and most frequent increases across health conditions. Multiple specific health conditions were associated with increased risk of an EMS call including abdominal/genito-urinary, alcohol/drug, anaphylaxis/allergy, cardiovascular, metabolic/endocrine, diabetes, neurological, heat illness and dehydration, and psychological conditions. Conclusions Extreme heat increases the risk of EMS calls in King County, WA, with effects demonstrated in relatively younger populations and more health conditions than those identified in previous analyses.