Occupational heat exposure and injury risk in Washington State construction workers

Thesis (Ph.D.)--University of Washington, 2018Introduction: The primary objectives of this research were to: 1) assess the relationship between heat exposure and occupational traumatic injuries in Washington State; and 2) assess heat exposure and the relationship between heat stress and psychomotor vigilance and balance in a population at high risk for injuries and heat related illness. Methods: We conducted an epidemiologic study and a field study. First, we assessed the relationship between maximum daily humidex and Washington State Fund workers’ compensation injuries in outdoor construction workers from 2000-2012 using a case-crossover design and high-resolution meteorological data. Second, we collected full-shift measurements of heat exposure and tests of psychomotor vigilance and balance in a sample of 22 commercial roofing workers in the Greater Seattle area in a repeated-measures study during the summer and fall of 2016. Heat exposure was compared across three spatial resolutions (regional, area, and personal). The association between heat stress, specifically the mean one-hour difference between the worksite wet bulb globe temperature and the recommended exposure limit (ΔREL), and PVT and balance outcomes were modeled using linear GEE. Results: We observed a traumatic injury odds ratio (OR) in outdoor WA construction workers of 1.0053 (95% CI 1.003, 1.007) per °C change in humidex. We report a positive mean (95% confidence interval) difference between personal- and area-level temperature of 4.4 (4.1, 4.7)°C. The direction of the difference between regional and area monitors varied by site. We observed a positive (detrimental) association (0.3; 95% CI -3.0, 3.5) and a negative association (-0.9; 95% CI -1.7, -0.1) between heat stress and PVT and balance, respectively. Post hoc interaction analyses of heat stress and dehydration yielded positive associations of heat stress with psychomotor outcomes. Conclusion: In the case-crossover study, increasing humidex was associated with increasing traumatic injury risk. In the field study of commercial roofing workers, personal temperature measurements were consistently higher than area temperature measurements, and the difference between regional and area temperatures varied in direction by site. No decrements in psychomotor vigilance or postural sway were observed with the low levels of heat stress measured in this study, however dehydration may modify this effect

Perceptions of Work-Related Health and Cancer Risks Among Women Firefighters

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

Prevalence and predictors of colon and prostate cancer screening among volunteer firefighters: The United States Firefighter Cancer Assessment and Prevention Study

Although firefighters have increased risk for colon and prostate cancer, limited information exists on screening practices for these cancers in volunteer firefighters who compose two-thirds of the US fire service. We estimated the prevalence of colon and prostate cancer screening among volunteer firefighters using eligibility criteria from 4 evidence-based screening recommendations and evaluated factors influencing screening. We evaluated colon (n = 569) and prostate (n = 498) cancer screening prevalence in a sample of US volunteer firefighters using eligibility criteria from the US Preventive Services Taskforce (USPSTF), National Fire Protection Association, American Cancer Society, and National Comprehensive Cancer Network. We assessed associations with fire service experience, demographics, and cancer risk perception based on USPSTF guidelines. For those eligible based on USPSTF guidelines, colon and prostate cancer screening prevalence was 51.7% (95% CI: 45.7, 57.8) and 48.8% (95% CI: 40.0, 57.6), respectively. Higher odds of colon and prostate cancer screening were observed with older age and with some college education compared to those with less education. Fire service experience and cancer risk perception were not associated with screening practices. This is the first large study to assess colon and prostate cancer screening among US volunteer firefighters based on different screening guidelines. Our findings suggest gaps in cancer prevention efforts in the US volunteer fire service. Promoting cancer screening education and opportunities for volunteer firefighters by their fire departments, healthcare professionals, and public health practitioners, may help to address the gaps

Firefighting, per- and polyfluoroalkyl substances, and DNA methylation of genes associated with prostate cancer risk

Prostate cancer is the leading incident cancer among men in the United States. Firefighters are diagnosed with this disease at a rate 1.21 times higher than the average population. This increased risk may result from occupational exposures to many toxicants, including per- and polyfluoroalkyl substances (PFAS). This study assessed the association between firefighting as an occupation in general or PFAS serum levels, with DNA methylation. Only genomic regions previously linked to prostate cancer risk were selected for analysis: GSTP1, Alu repetitive elements, and the 8q24 chromosomal region. There were 444 male firefighters included in this study, with some analyses being conducted on fewer participants due to missingness. Statistical models were used to test associations between exposures and DNA methylation at CpG sites in the selected genomic regions. Exposure variables included proxies of cumulative firefighting exposures (incumbent versus academy status and years of firefighting experience) and biomarkers of PFAS exposures (serum concentrations of 9 PFAS). Proxies of cumulative exposures were associated with DNA methylation at 15 CpG sites and one region located within FAM83A (q-value <0.1). SbPFOA was associated with 19 CpG sites (q < 0.1), but due to low detection rates, this PFAS was modeled as detected versus not detected in serum. Overall, there is evidence that firefighting experience is associated with differential DNA methylation in prostate cancer risk loci, but this study did not find evidence that these differences are due to PFAS exposures specifically

Per- and polyfluoroalkyl substances, epigenetic age and DNA methylation: a cross-sectional study of firefighters

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. Lay abstract Per- and poly-fluoroalkyl substances (PFASs) are a group of toxic chemicals that populations around the world are widely exposed to through contaminated water and consumer products. Firefighters can also be exposed to PFASs from occupational practices. Epigenetic modifications, including DNA methylation, regulate gene expression. It can be modified by environmental exposures such as PFASs, which contribute to the development of diseases including cancer. We measured the concentrations of nine PFASs in samples from firefighters and profiled DNA methylation across the genome. Three PFASs were linked with accelerated epigenetic age, a marker associated with many diseases. Four PFASs were associated with altered DNA methylation levels at specific genes. These results may indicate how PFASs are harmful to health and merit further exploration

Serum per‐ and polyfluoroalkyl substance concentrations in four municipal US fire departments

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.Federal Emergency Management AgencyOpen access articleThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]