Cancer Incidence and Mortality among Firefighters: An Overview of Epidemiologic Systematic Reviews

Assessment of cancer biomarkers in the Grenfell firefighter cohort study

Firefighters are exposed to a diverse range of harmful substances, including polycyclic aromatic hydrocarbons, benzene, and other carcinogens. These toxic compounds induce DNA damage, often causing the formation of DNA adducts and other lesions that can contribute to the development of various diseases, including cancer. Recent advancements in molecular diagnostics have shown that circulating cell-free DNA (cfDNA) in plasma is a valuable biomarker for detecting DNA damage and disease states. In this study, we explored whether changes in the quantity and quality of plasma cfDNA might reveal DNA lesions or serve as early markers for diseases such as cancer in UK firefighters. Whilst there are few published epidemiological studies of risk of cancer in UK firefighters, there are none on molecular markers in this population. All the 685 firefighters who participated in the study were employed by the London Fire Brigade in 2017; many of them also attended the Grenfell Tower fire, the most devastating fire to occur in the UK in modern history. In this exploratory analysis, we sought to gain insights into the potential long-term health impacts of toxic smoke exposure on these first responders by analysing both the concentration of cfDNA present and specific genetic alterations in cfDNA. Using next-generation sequencing and a panel that detects pathogenic DNA variants linked to various cancers, we analysed a subset of 261 firefighters. Our findings revealed that 11 firefighters carried pathogenic DNA variants associated with cancer, but we found no association between fire smoke exposure and the presence of these variants.

Epidemiology and Risk Factors for Testicular Cancer: A Systematic Review

BACKGROUND AND OBJECTIVE

Testicular germ cell tumors (TGCTs) are globally rare, although incidence significantly varies across global geographic regions and ethnicities. Recent decades have seen an unexplained increase in incidence. This review investigates the changing epidemiology of TGCT and identifies key risk factors.

METHODS

A systematic review following the Preferred Reporting Items for Systematic Reviews and Meta-analyses 2020 statement was conducted. After screening and risk-of-bias assessment, 53 reports on significant and updated topics on TGCT epidemiology and risk factors were included for narrative synthesis. Of these, 26 were selected for quantitative synthesis.

KEY FINDINGS AND LIMITATIONS

Projections suggest a continued increase in global TGCT incidence, even in populations with historically low incidence. Genetic predisposition, particularly single-nucleotide polymorphisms, accounts for approximately 44% of TGCT heritability. In utero exposure to endocrine-disrupting chemicals, cryptorchidism, infertility, high height, behavioral factors such as marijuana consumption, and environmental or occupational exposures to potentially harmful substances are associated with higher TGCT risk, with variable strength of evidence. Meta-analyses confirmed a significant association between prenatal/early-life risk factors and TGCT incidence (odds ratio 1.44). Limitations include constrained evidence quality, heterogeneity in study types, and a limited volume of data supporting each topic.

CONCLUSIONS AND CLINICAL IMPLICATIONS

TGCT pathogenesis is influenced by genetic predisposition and exposures during early life. The rising incidence may reflect socioeconomic changes and migration patterns, which determine variation in population exposure to risk factors. TGCT epidemiology remains controversial and requires further research and the implementation of optimal screening programs considering the rising incidence and consequent impact on global health and socioeconomic systems.

Physiological responses to repeated heat exposure under equal work load conditions

Objectives. This study aimed to verify the responses of skin temperature, oxygen saturation, blood pressure, rate pressure product (RPP), heart rate (HR) and HR variability after continuous and intermittent exposure to heat from a fire, keeping the work load equal between the conditions. Methods. Sixteen men from a fire department were subjected to two experimental conditions: continuous exposure to the heat from a fire for 30 uninterrupted minutes (1 × 30 min); and intermittent exposure to the heat of the fire organized by two 15-min re-entries of exposure to the heat interspersed with 10 min of non-exposure (2 × 15 min). Results. The main finding was lower percentage changes in HR (+1.7% vs +38% vs +26%), mean normal interval (-0.97% vs -26% vs -20%), RMSSD (-5.0% vs -62% vs -48%) and RPP (+0.79% vs +38% vs 34%) in re-exposure (15-30 min) when compared for 0-30 min and 0-15 min, respectively. Conclusion. Under equal workloads, intermittent exposure to heat is an efficient strategy for fire suppression activities. In addition to skin temperature and HR, RPP constitutes another variable to monitor firefighter health between re-entries, as it is easy to administer, inexpensive and reflects cardiac overload.

Examination of Firefighting as an Occupational Exposure Criteria for Lung Cancer Screening

PURPOSE

Firefighting is known to be carcinogenic to humans. However, current lung cancer screening guidelines do not account for occupational exposure. We hypothesize that firefighting is an independent risk factor associated with the development of high-risk lung nodules on low-dose CT (LDCT).

METHODS

Members of a firefighter's union underwent LDCT at a single institution between April 2022 and June 2023 within a lung cancer screening program. Results were interpreted by designated chest radiologists and reported using the Lung-RADS scoring system. Demographic and radiographic data were recorded, and summary statistics are reported.

RESULTS

1347 individuals underwent lung cancer screening, with a median age of 51 years (IQR 42-58), including 56 (4.2%) females. Overall, 899 (66.7%) were never smokers, 345 (25.6%) were former smokers, and 103 (7.7%) were current smokers. There were 41 firefighters (3.0%) who had high-risk (Lung-RADS 3 or 4) nodules requiring intervention or surveillance, of which 21 (1.5%) were Lung-RADS 3 and 20 (1.5%) that were Lung-RADS 4. Of the firefighters with high-risk nodules, only 6 (14.6%) were eligible for LDCT based on current screening guidelines. There were 7 high-risk nodules (0.5%) that required procedural intervention, 6 (85.7%) of which were from the non-screening eligible cohort. There were also 20 never-smoking firefighters (57.1%) with high-risk nodules that were non-screening eligible.

CONCLUSION

Firefighting, even in the absence of smoking history, may be associated with the development of high-risk lung nodules on LDCT. Carefully selected occupational exposures should be considered in the development of future lung cancer screening guidelines.

Perceptions of Preventable Cancer Burden Among US-Based Firefighters: A Mixed Methods Cross-Sectional Study

OBJECTIVE

Characterize experiences with cancer and perceptions of the preventable cancer burden attributable to diet among firefighters.

DESIGN

A cross-sectional survey was distributed to assess cancer history and perceptions of cancer.

SETTING

US.

PARTICIPANTS

US-based firefighters.

MAIN OUTCOME MEASURE(S)

History of cancer, perceptions of cancer, and perceptions of diet as a means to prevent cancer.

ANALYSIS

Descriptive statistics and use of the Behaviour Change Technique Taxonomy v1 (BCTTv1) to evaluate qualitative responses.

RESULTS

A total of 471 firefighters participated. Nearly half (48.4%) voiced they strongly agreed that they were at risk for cancer, whereas 44.6% agreed that changing diet could decrease cancer risk. The most common BCTTv1 codes focused on types of education, including "Instruction on how to perform the behavior" (45.1%, n = 189), followed by those centered on behavior execution (eg, "Action planning" [24.8%, n = 104]). Qualitatively, many were concerned about misinformation.

CONCLUSIONS AND IMPLICATIONS

Firefighters acknowledge the role of diet in cancer risk and have a desire for knowledge and behavioral support (eg, goal setting) that includes an emphasis on evidence and tackling misinformation. This information should serve as the basis of future interventions that target diet.

Parental occupations at birth and risk of adult testicular germ cell tumors in offspring: a French nationwide case-control study

Background

Testicular germ cell tumors (TGCT) are the most frequent cancer in young men in developed countries. Parental occupational exposures during early-life periods are suspected to increase TGCT risk. The objective was to estimate the association between parental occupations at birth and adult TGCT.

Methods

A case-control study was conducted, including 454 TGCT cases aged 18-45 from 20 French university hospitals, matched to 670 controls based on region and year of birth. Data collected from participants included parental jobs at birth coded according to the International Standard Classification of Occupation-1968 and the French nomenclature of activities-1999. Odds ratios (OR) for TGCT and 95% confidence intervals (CI) were estimated using conditional logistic regression, adjusting for TGCT risk factors.

Results

Paternal jobs at birth as service workers (OR = 1.98, CI 1.18-3.30), protective service workers (OR = 2.40, CI 1.20-4.81), transport equipment operators (OR = 1.96, CI 1.14-3.37), specialized farmers (OR = 2.66, CI 1.03-6.90), and maternal jobs as secondary education teachers (OR = 2.27, CI 1.09-4.76) or in secondary education (OR = 2.35, CI 1.13-4.88) were significantly associated with adult TGCT. The risk of seminoma was increased for the above-mentioned paternal jobs and that of non-seminomas for public administration and defence; compulsory social security (OR = 1.99, CI 1.09-3.65); general, economic, and social administration (OR = 3.21, CI 1.23-8.39) for fathers; and secondary education teacher (OR = 4.67, CI 1.87-11.67) and secondary education (OR = 3.50, CI 1.36-9.01) for mothers.

Conclusion

Some paternal jobs, such as service workers, transport equipment operators, or specialized farmers, and maternal jobs in secondary education seem to be associated with an increased risk of TGCT with specific features depending on the histological type. These data allow hypotheses to be put forward for further studies as to the involvement of occupational exposures in the risk of developing TGCT, such as exposure to pesticides, solvents, or heavy metals.

Risk factors for glioblastoma are shared by other brain tumor types

The reported risk factors for glioblastoma (GBM), i.e., ionizing radiation, Li-Fraumeni syndrome, Neurofibromatosis I, and Turcot syndrome, also increase the risk of other brain tumor types. Risk factors for human GBM are associated with different oncogenic mutation profiles. Pedigreed domestic dogs with a shorter nose and flatter face (brachycephalic dogs) display relatively high rates of glioma formation. The genetic profiles of canine gliomas are also idiosyncratic. The association of putatively different mutational patterns in humans and canines with GBM suggests that different oncogenic pathways can result in GBM formation. Strong epidemiological evidence for an association between exposure to chemical carcinogens and an increased risk for development of GBM is currently lacking. Ionizing radiation induces point mutations, frameshift mutations, double-strand breaks, and chromosomal insertions or deletions. Mutational profiles associated with chemical exposures overlap with the broad mutational patterns seen with ionizing radiation. Weak statistical associations between chemical exposures and GBM reported in epidemiology studies are biologically plausible. Molecular approaches comparing reproducible patterns seen in spontaneous GBM with analogous patterns found in GBMs resected from patients with known significant exposures to potentially carcinogenic chemicals can address difficulties presented by traditional exposure assessment.

Air pollution inside fire stations: State-of-the-art and future challenges

Firefighters are frequently exposed to products of combustion and pyrolysis. Exposure to these substances occurs not only during fires but also at fire stations, particularly where fire equipment and fire uniforms are stored after firefighting operations. The aims of this study were to review the research on the concentrations of various air pollutants in fire stations, identify the limitations and strengths of such research, identify research gaps and related future challenges, and highlight potential solutions for reducing firefighter exposure to air pollution at fire stations. A total of 32 articles published in international journals during 1987-2023 were selected for analysis. The most frequently studied pollutants in fire stations were polycyclic aromatic hydrocarbons, particulate matter, and diesel particulate matter. Research was most often conducted on changing rooms and garages. Firefighting equipment, personal protective equipment, fire trucks, and combustion tools were identified as the main sources of pollution at fire stations. Recommendations aimed at reducing the concentration of pollutants in fire stations were mainly concerned with the systematic decontamination of equipment and the introduction of ventilation solutions that would remove exhaust fumes from garages. This in-depth literature review indicates a lack of comprehensive research on the state and quality of air at fire stations. It also highlights the emerging need for more knowledge on the concentrations of air pollutants in fire stations, health exposure related to these substances, and an analysis of the effectiveness of the proposed solutions.

Toward the future of firefighter gear: Assessing fluorinated and non-fluorinated outer shells following simulated on-the-job exposures

In 2022, the occupation of firefighting was categorized as a "Group 1" carcinogen, meaning it is known to be carcinogenic to humans. The personal protective equipment that structural firefighters wear is designed to safeguard them from thermal, physical, and chemical hazards while maintaining thermo-physiological comfort. Typically, the outer layer of structural turnout gear is finished with a durable water and oil-repellent (DWR) based on per- and polyfluoroalkyl substances (PFAS) that helps limit exposure to water and hazardous liquids. The PFAS-based aqueous emulsion typically used in DWR finishes is highly persistent and can cause various health problems if absorbed into the body through ingestion, inhalation, and/or dermal absorption. In response, the U.S. Fire Service has begun using non-PFAS water repellants in firefighter turnout gear. This study aims to evaluate the performance of both traditional PFAS-based and alternative non-PFAS outer shell materials. The study involved exposing both PFAS-based and non-PFAS DWR outer shell materials in turnout composites to simulated job exposures (i.e., weathering, thermal exposure, and laundering) that artificially aged the materials. After exposures, samples were evaluated for repellency, durability, thermal protection, and surface chemistry analysis to determine any potential performance trade-offs that may exist. Non-PFAS outer shell fabrics were found not to be diesel/oil-repellent, posing a potential flammability hazard if exposed to diesel and subsequent flame on an emergency response. Both PFAS-based and non-PFAS sets of fabrics performed similarly in terms of thermal protective performance, tearing strength, and water repellency. The surface analysis suggests that both PFAS and non-PFAS chemistries can degrade and shed from fabrics during the aging process. The study indicates that firefighters should be educated and trained regarding the potential performance trade-offs, such as oil absorption and flammability concerns when transitioning to non-PFAS outer shell materials.

Testicular germ cell tumour risk by occupation and industry: a French case-control study - TESTIS

OBJECTIVE

Testicular germ cell tumours (TGCT) are the most common cancer in men of working age and its incidence has increased notably over the past 40 years. Several occupations have been identified as potentially associated with TGCT risk. The aim of this study was to further explore the relationship between occupations, industries and TGCT risk in men aged 18-45 years.

METHODS

The TESTIS study is a multicenter case-control study conducted between January 2015 and April 2018 in 20 of 23 university hospital centers in metropolitan France. A total of 454 TGCT cases and 670 controls were included. Full job histories were collected. Occupations were coded according to the International Standard Classification of Occupation 1968 version (ISCO-1968) and industry according to the 1999 version of Nomenclature d'Activités Française (NAF-1999). For each job held, ORs and 95% CIs were estimated using conditional logistic regression.

RESULTS

A positive association was observed between TGCT and occupation as agricultural, animal husbandry worker (ISCO: 6-2; OR 1.71; 95% CI (1.02 to 2.82)), as well as salesman (ISCO: 4-51; OR 1.84; 95% CI (1.20 to 2.82)). An increased risk was further observed among electrical fitters and related, electrical and electronics workers employed for 2 years or more (ISCO: 8-5; OR≥2 years 1.83; 95% CI (1.01 to 3.32)). Analyses by industry supported these findings.

CONCLUSIONS

Our findings suggest that agricultural, electrical and electronics workers, and salesmen workers experience an increased risk of TGCT. Further research is needed to identify the agents or chemicals in these high-risk occupations which are relevant in the TGCT development.

TRIAL REGISTRATION NUMBER

NCT02109926.

Military occupation and testicular germ cell tumour risk among US Air Force servicemen

OBJECTIVES

Testicular germ cell tumours (TGCTs) are the most commonly diagnosed malignancy among active duty US military servicemen. Occupational risk factors may play a role in TGCT aetiology, although the evidence is inconclusive. The objective of our study was to investigate associations between military occupations and TGCT risk among US Air Force (USAF) servicemen.

METHODS

This nested case-control study among active duty USAF servicemen obtained information on military occupations for 530 histologically confirmed TGCT cases diagnosed during 1990-2018 and 530 individually matched controls. We determined military occupations using Air Force Specialty Codes ascertained at two time points: at case diagnosis and at a time point on average 6 years earlier. We computed adjusted ORs and 95% CIs from conditional logistic regression models to evaluate associations between occupations and TGCT risk.

RESULTS

The mean age at TGCT diagnosis was 30 years. Increased TGCT risk was observed for pilots (OR=2.84, 95% CI: 1.20-6.74) and servicemen with aircraft maintenance jobs (OR=1.85, 95% CI: 1.03-3.31) who held those jobs at both time points. Fighter pilots (n=18) and servicemen with firefighting jobs (n=18) at the time of case diagnosis had suggestively elevated TGCT odds (OR=2.73, 95% CI: 0.96-7.72 and OR=1.94, 95% CI: 0.72-5.20, respectively).

CONCLUSIONS

In this matched, nested case-control study of young active duty USAF servicemen, we found that pilots and men with aircraft maintenance jobs had elevated TGCT risk. Further research is needed to elucidate specific occupational exposures underlying these associations.

Firefighting and Cancer: A Meta-analysis of Cohort Studies in the Context of Cancer Hazard Identification

Objective

We performed a meta-analysis of epidemiological results for the association between occupational exposure as a firefighter and cancer as part of the broader evidence synthesis work of the IARCMonographs program.

Methods

A systematic literature search was conducted to identify cohort studies of firefighters followed for cancer incidence and mortality. Studies were evaluated for the influence of key biases on results. Random-effects meta-analysis models were used to estimate the association between ever-employment and duration of employment as a firefighter and risk of 12 selected cancers. The impact of bias was explored in sensitivity analyses.

Results

Among the 16 included cancer incidence studies, the estimated meta-rate ratio, 95% confidence interval (CI), and heterogeneity statistic (I2) for ever-employment as a career firefighter compared mostly to general populations were 1.58 (1.14-2.20, 8%) for mesothelioma, 1.16 (1.08-1.26, 0%) for bladder cancer, 1.21 (1.12-1.32, 81%) for prostate cancer, 1.37 (1.03-1.82, 56%) for testicular cancer, 1.19 (1.07-1.32, 37%) for colon cancer, 1.36 (1.15-1.62, 83%) for melanoma, 1.12 (1.01-1.25, 0%) for non-Hodgkin lymphoma, 1.28 (1.02-1.61, 40%) for thyroid cancer, and 1.09 (0.92-1.29, 55%) for kidney cancer. Ever-employment as a firefighter was not positively associated with lung, nervous system, or stomach cancer. Results for mesothelioma and bladder cancer exhibited low heterogeneity and were largely robust across sensitivity analyses.

Conclusions

There is epidemiological evidence to support a causal relationship between occupational exposure as a firefighter and certain cancers. Challenges persist in the body of evidence related to the quality of exposure assessment, confounding, and medical surveillance bias.

Cancer risk and mortality among firefighters: a meta-analytic review

Background

Firefighting is a hazardous occupation that is associated with an increased risk of select cancers. The number of studies has grown in recent years allowing for a synthesis of findings.

Methods

Following PRISMA guidelines, multiple electronic databases were searched to identify studies on firefighter cancer risk and mortality. We computed pooled standardized incidence risk (SIRE) and standardized mortality estimates (SMRE), tested for publication bias, and conducted moderator analyses.

Results

Thirty-eight studies published between 1978 and March 2022 were included for final meta-analysis. Overall, cancer incidence and mortality were significantly lower for firefighters (SIRE = 0.93; 95% CI: 0.91-0.95; SMRE = 0.93; 95% CI: 0.92 - 0.95) compared to the general population. Incident cancer risks were significantly higher for skin melanoma (SIRE = 1.14; 95% CI:1.08 - 1.21), other skin cancers (SIRE = 1.24; 95% CI:1.16-1.32), and prostate cancer (SIRE = 1.09; 95% CI: 1.04-1.14). Firefighters showed higher mortality for rectum (SMRE = 1.18; 95% CI: 1.02-1.36), testis (SMRE = 1.64; 95% CI: 1.00-2.67), and non-Hodgkin lymphoma (SMRE = 1.20; 95% CI: 1.02-1.40). There was evidence of publication bias for SIRE and SMRE estimates. Some moderators explained variations in study effects, including study quality scores.

Conclusion

Firefighters are at higher risk for several cancers; to the extent that some (e.g., melanoma and prostate) are screening amenable, more study into firefighter-specific recommendations for cancer surveillance is needed. Moreover, longitudinal studies with more detailed data on the specific length and types of exposures are necessary, as well as on unstudied subtypes of cancers (e.g., subtypes of brain cancer and leukemias) are needed.

Cancer and Potential Prevention with Lifestyle among Career Firefighters: A Narrative Review

Career firefighters are at considerable risk for chronic diseases, including an increased risk of various cancers, compared to the general population. Over the last two decades, several systematic reviews and large cohort studies have demonstrated that firefighters have statistically significant increases in overall and site-specific cancer incidence and site-specific cancer mortality compared to the general population. Exposure assessment and other studies have documented exposures to a variety of carcinogens in fire smoke and within the fire station. Other occupational factors such as shift work, sedentary behavior, and the fire service food culture may also contribute to this working population's increased cancer risk. Furthermore, obesity and other lifestyle behaviors such as tobacco use, excessive alcohol consumption, poor diet, inadequate physical activity, and short sleep duration have also been associated with an increased risk of certain firefighting-associated cancers. Putative prevention strategies are proposed based on suspected occupational and lifestyle risk factors.

Risk Factors for Testicular Cancer: Environment, Genes and Infections-Is It All?

The incidence of testicular cancer is steadily increasing over the past several decades in different developed countries. If on one side better diagnosis and treatment have shone a light on this disease, on the other side, differently from other malignant diseases, few risk factors have been identified. The reasons for the increase in testicular cancer are however unknown while risk factors are still poorly understood. Several studies have suggested that exposure to various factors in adolescence as well as in adulthood could be linked to the development of testicular cancer. Nevertheless, the role of environment, infections, and occupational exposure are undoubtedly associated with an increase or a decrease in this risk. The aim of this narrative review is to summarize the most recent evidence regarding the risk factors associated with testicular cancer, starting from the most commonly evaluated (cryptorchidism, family history, infections) to the newer identified and hypothesized risk factors.

Firefighters' exposure to per-and polyfluoroalkyl substances (PFAS) as an occupational hazard: A review

The term "firefighter" and "cancer" have become so intertwined in the past decade that they are now nearly inseparable. Occupational exposure of firefighters to carcinogenic chemicals may increase their risk of developing different types of cancer. PFAS are one of the major classes of carcinogenic chemicals that firefighters are exposed to as occupational hazard. Elevated levels of PFAS have been observed in firefighters' blood serum in recent studies. Possible sources of occupational exposure to PFAS include turnout gear, aqueous film-forming foam, and air and dust at both the fire scene and fire station. Preliminary discussion on PFAS includes definition, classification, and chemical structure. The review is then followed by identifying the sources of PFAS that firefighters may encounter as an occupational hazard. The structural properties of the PFAS used in identified sources, their degradation, and exposure pathways are reviewed. The elevated level of PFAS in the blood serum and how this might associate with an increased risk of cancer is discussed. Our review shows a significant amount of PFAS on turnout gear and their migration to untreated layers, and how turnout gear itself might be a potential source of PFAS exposure. PFAS from aqueous film-forming foams (AFFF), air, and dust of fire stations have been already established as potential exposure sources. Studies on firefighters' cancer suggest that firefighters have a higher cancer risk compared to the general population. This review suggests that increased exposure to PFAS as an occupational hazard could be a potential cancer risk for firefighters.

Longitudinal lung function in urban firefighters: A group-based multi-trajectory modelling approach

BACKGROUND AND OBJECTIVE

Urban firefighters are routinely exposed to both physical and chemical hazards that can negatively impact lung health, but it is unclear if firefighters experience accelerated decline in spirometry parameters due to chronic exposure and acute insults. This study aimed to describe sub-groups of firefighters with differing spirometry trajectories and examine the relationship between the identified trajectories and demographic, lifestyle and occupational characteristics.

METHODS

Data from six waves of the Respiratory Function Measurement and Surveillance for South Australian Metropolitan Fire Service Study (2007-2019) were used to identify spirometry parameter z-score trajectories, using group-based multi-trajectory modelling (GBMTM). Analysis of variance and chi-square statistics were used to assess trajectory group differences in baseline self-reported demographic, lifestyle and occupational characteristics.

RESULTS

In the 669 included firefighters, we identified five trajectories for the combination of Forced Expiratory Volume in the first second z-score (FEV₁ z), Forced Vital Capacity z-score (FVCz) and the ratio of FEV₁ and FVC z-score (FEV₁ /FVCz). There were three stable trajectories of low, average and very high lung function and two declining trajectories of average and high lung function. Analysis of subgroup characteristics revealed no significant differences between expected and actual group proportions for the occupational characteristics of years of service and respiratory protection use. Significant differences were seen in respiratory health and body mass index.

CONCLUSION

GBMTM defined distinct, plausible spirometry trajectory sub-groups. Firefighter longitudinal spirometry trajectory group membership was associated with BMI and respiratory disease or symptoms but not with self-reported smoking history or occupational factors.

Scottish Firefighters Occupational Cancer and Disease Mortality Rates: 2000-2020

BACKGROUND

Increased mortality from cancers and other diseases has been reported in USA, Canadian, and Nordic firefighters. However, UK firefighters are understudied.

AIMS

To determine whether UK firefighters suffer increased mortality from cancers and other diseases when compared with the general population.

METHODS

Mortality from cancer and other diseases in Scottish male firefighters between 2000 and 2020 was compared with the general Scottish male population and expressed as standardized mortality ratios (SMRs) (with 95% confidence intervals, CI).

RESULTS

Significant overall excess cancer mortality was found for Scottish firefighters compared with the general population (SMR 1.61, CI 1.42-1.81). Scottish firefighters were nearly three times more likely to die of malignant neoplasms (unspecified sites) (SMR 2.71, CI 1.71-4.00). Excess cancer mortality was also found for several site-specific cancers, including prostate (SMR 3.80, CI 2.56-5.29), myeloid leukaemia (SMR 3.17, CI 1.44-5.58), oesophagus (SMR 2.42, CI 1.69-3.29) and urinary system (kidney and bladder) (SMR 1.94, CI 1.16-2.91). Mortality from neoplasms of unknown behaviour was over six times greater in Scottish firefighters (SMR 6.37, CI 2.29-12.49). Additionally, significantly higher mortality was found for: acute ischaemic heart diseases (SMR 5.27, CI 1.90-10.33), stroke (SMR 2.69, CI 1.46-4.28), interstitial pulmonary diseases (SMR 3.04, CI 1.45-5.22), renal failure (SMR 3.28, CI 1.18-6.44) and musculoskeletal system diseases (SMR 5.64, CI 1.06-13.83).

CONCLUSIONS

UK firefighters suffer significant excess mortality from cancer and other diseases when compared with the general population. Preventative health monitoring and presumptive legislation are urgently required to protect UK firefighters' health.

Cancer in female firefighters: The clinicobiological, psychological, and social perspectives

Objectives

This study explored how demographic characteristics, life experiences, and firefighting exposures have an impact on cancer among female firefighters, and described the types and biologic characteristics of cancers as reported by women in the fire service.

Methods

The online survey was available from June 2019 to July 2020. Questions related to demographic characteristics, lifestyle factors, firefighting exposures, and cancer diagnoses. Descriptive analyses characterized variables by the presence or absence of cancer. Qualitative data provided insight into both firefighting and cancer experiences among women.

Results

There were 1,344 female firefighter respondents from 12 different countries, 256 of whom provided information on their cancer diagnosis. North American respondents made up 92% of the total. Those with cancer were older, had been in the fire service longer, had more career fires and toxic exposures, and were less likely to still be in active service. They also reported more tobacco use, and more full-term pregnancies. There were no differences in family history of cancer between the two groups. The average age at diagnosis was 39.0 years. The major types of cancer reported included breast (25.4%), cervical (21.1%), melanoma (20.7%), base cell/skin (16.4%), and uterine (14.8%). The cancer was detected when seeking medical attention for symptoms (42.1%), during routine health screening (29.8%), and during specific cancer screening (28.1%). The stage of cancer was reported by 44.5%, and 30.9% included the histopathological grade. Treatments included surgery (72.7%), chemotherapy (14.8%), radiotherapy (13.7%), and observation (13.7%). Challenges associated with cancer included psychosocial (33.2%), financial (18.8%), physical (6.6%), and spiritual (6.3%). Concerns about reporting a cancer experience to their employer included the desire to keep health information private (11.3%), a feeling of vulnerability (7.4%), and being perceived as weak (7.0%). Lack of support from their employer or insurer was also noted.

Conclusion

Female firefighters experienced a wide variety of different types of cancers which may come earlier than similar cancers in the public. These findings can help inform resource allocation, the development of new policies, and the need for broader presumptive coverage to support female firefighters diagnosed with cancer.

Non-cancer health risks in firefighters: a systematic review

osFirefighters are occupationally exposed to hazardous factors that may increase their risk of disease. However, non-cancer disease risk in firefighters has not been systematically examined. This systematic review aimed to identify non-cancer disease risk in firefighters and determine whether the risk differs according to job characteristics. We searched the Cochrane Library, Embase, PubMed, and KoreaMed databases using relevant keywords from their inception to April 30, 2021. The Risk of Bias Assessment Tool for Non-randomized Studies version 2.0 was used to assess the quality of evidence. Due to study heterogeneity, a narrative synthesis was presented. The systematic literature search yielded 2,491 studies, of which 66 met the selection and quality criteria. We confirmed that the healthy worker effect is strong in firefighters as compared to the general population. We also identified a significant increase in the incidence of lumbar disc herniation, lower back pain, angina pectoris, acute myocardial infarction, and post-traumatic stress disorder (PTSD) in firefighters compared to other occupational groups. Contradictory results for the risk of PTSD and anxiety disorders related to rank were reported. Sufficient evidence for increased risk of lumbar disc herniation, lower back pain, angina pectoris, acute myocardial infarction, and PTSD was available. The risk of non-cancer diseases varied depending on job type, years of service, and rank. However, caution should be exercised when interpreting the results because the classification criteria for firefighters' jobs and ranks differ by country.

Lifestyle and environmental factors may induce airway and systemic inflammation in firefighters

Health status depends on multiple genetic and non-genetic factors. Nonheritable factors (such as lifestyle and environmental factors) have stronger impact on immune responses than genetic factors. Firefighters work is associated with exposure to air pollution and heat stress, as well as: extreme physical effort, mental stress, or a changed circadian rhythm, among others. All these factors can contribute to both, short-term and long-term impairment of the physical and mental health of firefighters. Increased levels of some inflammatory markers, such as pro-inflammatory cytokines or C-reactive protein (CRP) have been observed in firefighters, which can lead to local, acute inflammation that promotes a systemic inflammatory response. It is worth emphasizing that inflammation is one of the main hallmarks of cancer and also plays a key role in the development of cardiovascular and respiratory diseases. This article presents possible causes of the development of an inflammatory reaction in firefighters, with particular emphasis on airway inflammation caused by smoke exposure.

Hierarchy of contamination control in the fire service: Review of exposure control options to reduce cancer risk

The international fire service community is actively engaged in a wide range of activities focused on development, testing, and implementation of effective approaches to reduce exposure to contaminants and the related cancer risk. However, these activities are often viewed independent of each other and in the absence of the larger overall effort of occupational health risk mitigation. This narrative review synthesizes the current research on fire service contamination control in the context of the National Institute for Occupational Safety and Health (NIOSH) Hierarchy of Controls, a framework that supports decision making around implementing feasible and effective control solutions in occupational settings. Using this approach, we identify evidence-based measures that have been investigated and that can be implemented to protect firefighters during an emergency response, in the fire apparatus and at the fire station, and identify several knowledge gaps that remain. While a great deal of research and development has been focused on improving personal protective equipment for the various risks faced by the fire service, these measures are considered less effective. Administrative and engineering controls that can be used during and after the firefight have also received increased research interest in recent years. However, less research and development have been focused on higher level control measures such as engineering, substitution, and elimination, which may be the most effective, but are challenging to implement. A comprehensive approach that considers each level of control and how it can be implemented, and that is mindful of the need to balance contamination risk reduction against the fire service mission to save lives and protect property, is likely to be the most effective.

Reply to Guidotti, T. Comment on "Laroche, E.; L'Espérance, S. Cancer Incidence and Mortality among Firefighters: An Overview of Epidemiologic Systematic Reviews. Int. J. Environ. Res. Public Health 2021, 18, 2519"

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Assessment of Volatile Compound Transference through Firefighter Turnout Gear

There is high concern about the exposure of firefighters to toxic products or carcinogens resulting from combustion during fire interventions. Firefighter turnout gear is designed to protect against immediate fire hazards but not against chemical agents. Additionally, the decontamination of firefighter personal protective equipment remains unresolved. This study evaluated the feasibility of a screening method based on headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS) in combination with chemometrics (cluster analysis, principal component analysis, and linear discriminant analysis) for the assessment of the transference of volatile compounds through turnout gear. To achieve this, firefighter turnout gears exposed to two different fire scenes (with different combustion materials) were directly analyzed. We obtained a spectral fingerprint for turnout gears that were both exposed and non-exposed to fire scenes. The results showed that (i): the contamination of the turnout gears is different depending on the type of fire loading; and (ii) it is possible to determine if the turnout gear is free of volatile compounds. Based on the latest results, we concluded that HS-GC-IMS can be applied as a screening technique to assess the quality of turnout gear prior to a new fire intervention.

Temporal Aspects of the Association between Exposure to the World Trade Center Disaster and Risk of Cutaneous Melanoma

Rescue/recovery workers who responded to the World Trade Center (WTC) attacks were exposed to known/suspected carcinogens. Studies have identified a trend toward an elevated risk of cutaneous melanoma in this population; however, few found significant increases. Furthermore, temporal aspects of the association have not been investigated. A total of 44,540 non-Hispanic White workers from the WTC Combined Rescue/Recovery Cohort were studied between March 12, 2002 and December 31, 2015. Cancer data were obtained through linkages with 13 state registries. Poisson regression was used to estimate hazard ratios and 95% confidence intervals using the New York State population as the reference; change points in hazard ratios were estimated using profile likelihood. We observed 247 incident cases of melanoma. No increase in incidence was detected during 2002-2004. From 2005 to 2015, the hazard ratio was 1.34 (95% confidence interval = 1.18-1.52). A dose‒response relationship was observed by arrival time at the WTC site. Risk was elevated just over 3 years after the attacks. Whereas WTC-related exposures to UVR or other agents might have contributed to this result, exposures other than those at the WTC site, enhanced medical surveillance, and lack of a control group with a similar proportion of rescue/recovery workers cannot be discounted. Our results support continued study of this population for melanoma.