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This cross-sectional study of 193 aircraft rescue and firefighting (ARFF) personnel from six U.S. airport fire departments measured nine serum PFAS compounds and compared them with national reference data, finding that several PFAS—particularly PFHxS, PFOS isomers, and PFUnDA—were significantly elevated in firefighters, consistent with occupational exposure from aqueous film-forming foam (AFFF) and related sources. Regression analyses indicated that factors such as prior firefighting employment, age, and contaminated water were associated with higher PFAS levels, while recent changes in workplace practices, along with certain demographic variables, were linked to lower levels. Overall, the findings highlight that ARFF firefighters experience elevated PFAS exposure relative to the general population and suggest that modifications in firefighting practices may help reduce this occupational burden, though further research is needed to confirm effective mitigation strategies.
This study comprised of 303 U.S. firefighters explored whether exposure to per- and polyfluoroalkyl substances (PFAS)—chemicals often found in firefighting foams—could affect levels of small RNA molecules (miRNAs) linked to health outcomes. The researchers measured nine types of PFAS in the firefighters’ blood and compared them to their miRNA levels. They found that higher amounts of certain PFAS—especially the linear form of PFOS—were associated with changes in specific miRNAs that are known to regulate cancer‑related, immune system, thyroid, and neurological pathways. These findings suggest that PFAS exposure in firefighters may influence biological processes tied to long‑term disease risk.
This study compared serum PFAS (per- and polyfluoroalkyl substances) concentrations between incumbent and recruit firefighters and tracked changes over time in the recruit firefighters. It found that incumbent firefighters had lower levels of certain PFAS, like n-PFOA and PFNA, compared to recruits. Among recruits, most PFAS levels decreased over time, and no significant connection was found between fireground exposure and change in PFAS concentrations over time.
This study explored the connection between firefighting, PFAS exposure, and DNA methylation related to prostate cancer risk. Firefighters have a higher rate of prostate cancer compared to the general population, possibly due to occupational exposure to numerous toxicants including PFAS. DNA methylation is a regulator that turns genes on and off; its normal patterns can be disrupted by exposures and cumulative changes can contribute to development of diseases including cancers. In this study, we analyzed DNA methylation at specific genomic sites previously linked to prostate cancer, in 444 male firefighters. Results showed that firefighting experience was associated with changes in DNA methylation at several sites, but limited links were found between PFAS specifically and methylation at the sites measured. The findings suggest that cumulative exposures from firefighting may influence DNA methylation in prostate cancer risk areas.
This study examined the levels of per- and polyfluoroalkyl substances (PFAS) in the blood of firefighters from four U.S. fire departments. PFAS are man-made chemicals found in various products, including firefighting foams, and are known to persist in the environment and human body. The research revealed that firefighters had higher concentrations of certain PFAS compared to the general population, suggesting occupational exposure as a contributing factor. These findings highlight the need for further investigation into PFAS exposure sources and potential health effects among firefighters.
This study examined the levels of per- and polyfluoroalkyl substances (PFAS) in the blood of members of a suburban U.S. volunteer fire department. PFAS are synthetic chemicals used in various products, including firefighting foams, and have been linked to health problems. The study found that certain PFAS, such as perfluorododecanoic acid (PFDoA), were detected more frequently and at higher levels in firefighters compared to the general population. Additionally, the amount of PFDoA and perfluorodecanoic acid (PFDA) in the blood was higher in firefighters with more years of service. These results suggest that volunteer firefighters may be exposed to PFAS through their work, highlighting the need for further research and protective measures to reduce exposure.
This study explored how firefighters’ exposure to toxic chemicals, specifically per- and polyfluoroalkyl substances (PFAS), might affect their health at a molecular level. PFAS are chemicals commonly found in firefighting foam and equipment and consumer products. Often called ‘forever chemicals’, PFAS do not break down easily. PFAS accumulate in the body where they can adversely affect health. The researchers measured epigenetic marks – DNA methylation – which regulates how genes are turned on and off. They used the DNA methylation data to approximate biological age (called “epigenetic age”) and also to assess the status of all genes. The study found that firefighters with greater PFAS levels in their blood had greater epigenetic age –meaning their biological age looks older than their true age. PFAS levels were also linked to differences in DNA methylation patterns at specific genes, including genes linked to cancers and immune function. These molecular findings could help explain why people exposed to PFAS, over time, have a higher risk of developing health issues, including cancer and other chronic diseases. The study highlights potential biological processes behind the long-term health impacts of PFAS.
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In February 2023, a train transporting hazardous chemicals, including vinyl chloride and benzene, derailed and caught fire in East Palestine, Ohio, exposing over 350 firefighters – primarily volunteers - to a mixture of toxic chemicals. This study sought to determine whether responding to this incident changed microRNA expression. MicroRNA are small molecules that regulate gene expression and can serve as early biological indicators of disease long before a diagnosis occurs. Seventeen microRNAs were significantly altered in the blood of 62 firefighters who responded to the derailment compared to a group of 26 firefighters from the same region who did not. These specific markers are associated with health conditions including neurodegenerative diseases and cancers. Further research is needed to determine whether these molecular changes persist long term and contribute to disease.
This study looked at the health impacts of wildland-urban interface (WUI) firefighting, which happens when firefighters work in areas where forests and human development meet. These firefighters are exposed to dangerous smoke, burning materials, and toxic chemicals without always having proper protective gear. Since fires at the WUI can last a long time—days to weeks—the researchers wanted to see how this type of exposure might affect firefighters’ bodies, specifically by looking at changes in their genes. The study focused on epigenetics, which are modifications on top of DNA that influence gene expression without altering the underlying DNA code. Specifically, they looked at microRNAs (small molecules that turn off certain genes) and DNA methylation (a process that can turn genes on or off). The researchers took blood samples from 99 firefighters in Southern California at enrollment and again 10 months later. Between the baseline and follow-up, most of the firefighters had responded to at least one WUI fire. They found that 50 different microRNAs showed noticeable changes at the follow-up, indicating that exposures from WUI fires could alter how some genes are regulated. One of the microRNAs, hsa-miR-518c-3p, with a function known to protect against tumors, was associated with responding to WUI fires. However, the study did not find major changes in DNA methylation over time. In conclusion, the exposure to WUI fires seemed to change how some microRNAs were expressed but did not have a strong effect on DNA methylation. We do not know if there changes in gene regulation will contribute to adverse health outcomes later on.
This study comprised of 303 U.S. firefighters explored whether exposure to per- and polyfluoroalkyl substances (PFAS)—chemicals often found in firefighting foams—could affect levels of small RNA molecules (miRNAs) linked to health outcomes. The researchers measured nine types of PFAS in the firefighters’ blood and compared them to their miRNA levels. They found that higher amounts of certain PFAS—especially the linear form of PFOS—were associated with changes in specific miRNAs that are known to regulate cancer‑related, immune system, thyroid, and neurological pathways. These findings suggest that PFAS exposure in firefighters may influence biological processes tied to long‑term disease risk.
This study explored the relationship between epigenetic age acceleration (EAA) and microRNAs (miRNAs), which could serve as biomarkers for health, especially for aging and certain diseases. EAA is the difference between a person's biological age (as measured by epigenetic clocks) and their chronological age. The study analyzed DNA methylation and miRNA profiles from 332 firefighters, identifying 183 miRNAs associated with EAA. These miRNAs were linked to various aging-related conditions, such as metabolic and cardiovascular diseases, and several cancers. The research found that different epigenetic clocks, were associated with distinct miRNAs, with GrimAge and Horvath clocks showing stronger connections to disease-related pathways. The findings suggest that understanding the role of miRNAs in EAA could offer insights into the molecular causes of aging and related diseases.
This study examined the relationship between years of service and epigenetic aging among U.S. firefighters. Epigenetic age, which reflects biological aging, was assessed using DNA methylation markers in blood samples from 150 firefighters. The results indicated that longer service was associated with accelerated epigenetic aging, suggesting that the demanding nature of firefighting may contribute to faster biological aging. These findings highlight the importance of reducing firefighters’ occupational exposures and the need to identify treatments to reduce epigenetic age among firefighters.
Repeat measures of DNA methylation in an inception cohort of firefighters. (Goodrich et al., 2022)
This study investigated how exposure to firefighting activities might affect DNA methylation, a gene regulator, of firefighters over time. Firefighters face a higher risk of developing cancers and other health issues due to the hazardous environments they work in, which includes exposures to smoke and chemicals. One way these hazards might influence health is through changes in DNA methylation, which is a process that can turn genes on or off without altering the DNA code itself. The researchers looked at firefighters' DNA methylation at two points in time: before they started live fire training and again after they had worked for a period of 20 to 37 months. They wanted to see if their DNA methylation patterns changed after they began working as firefighters and if these changes were related to the number of fires they responded to. The study found that DNA methylation patterns did change at many genes, which might help explain how firefighting exposures can alter processes in the body that may eventually contribute to health problems like cancer. This research helps us understand how the body responds to firefighter exposures and provides clues for preventing health issues in the future.
Firefighters are at increased risk for multiple cancers. One major goal of the FFCCS is to identify exposures that are contributing to this risk and the biological mechanisms that they are working through. Among the general population and firefighters specifically, risks for some cancers vary according to race and ethnicity. The exposures and biological differences that contribute to these differences are not known. DNA methylation is one process in the body that controls whether genes or turned on or off. Importantly, DNA methylation is responsive to exposures, can differ by race/ethnicity, and widespread changes to DNA methylation are part of the development of cancers. Because of this, DNA methylation has the potential to serve as a marker of the impact of exposures and a predictor of disease risk. Researchers profiled DNA methylation in blood samples from Hispanic firefighters and firefighters from non-Hispanic backgrounds working in the same departments. The study found that DNA methylation patterns were different between firefighters from the two ethnicity groups. Based on the design of our study, we do not yet know whether these genes directly contribute to cancer risks in Hispanic firefighters. These findings could help us better understand how ethnicity and occupation may influence health risks and lead to more targeted health interventions that will protect all firefighters.
MicroRNA Changes in Firefighters. (Jeong et al., 2018)
This study compared microRNA (miRNA) expression between incumbent firefighters and new recruits to explore potential mechanisms linking firefighting to increased cancer risk. The study found that nine miRNAs had significantly different expression levels between the two groups. Six of these miRNAs, which were less expressed in incumbent firefighters, are known for their tumor-suppressing properties or association with cancer survival. The remaining three miRNAs, more expressed in incumbent firefighters, are linked to cancer promotion or neurological diseases. These findings suggest that firefighting may lead to epigenetic changes that could increase cancer risk.
DNA methylation among firefighters. (Zhou et al., 2019)
This study investigated DNA methylation patterns in firefighters to understand potential links to increased cancer risk. Researchers analyzed blood samples from 45 incumbent firefighters and 41 new recruits, identifying specific DNA methylation changes associated with years of service. Additional analyses revealed that these changes were related to cancer-related pathways, such as p53 signaling. These findings suggest that occupational exposures in firefighting may lead to epigenetic modifications contributing to elevated cancer risk, highlighting the importance of monitoring and mitigating such exposures to protect firefighters' health.
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Differential Metabolic Profiles by Training Fire Exposure in Female Firefighters (Liu, et al., 2026)
Female firefighters have higher risks for certain cancers and reproductive health problems, but it is not clear how fire exposure affects the body at a chemical level. This study looked at changes in metabolites in urine before and after live-fire training to better understand how training fires impact the body. Researchers compared pre- and post-fire samples while accounting for age and background factors. After training fires, many metabolites changed, showing that fire exposure affects normal body processes. The biggest changes were linked to metabolic pathways that are important for cell membranes and energy use. These pathways are also involved in inflammation, oxidative stress, and cell damage. These changes may help explain how repeated fire exposure could increase long-term health risks. Understanding these effects can support better training practices and firefighter health protections.
In January 2025, there were large fires in the Los Angeles area. Firefighters who responded to these fires were part of a study to see how their bodies changed after being exposed to smoke and other hazards. Scientists collected blood samples from 42 firefighters before and after the fires. They looked at the proteins in the blood, which can show how the body reacts to stress and injury.
After the fires, 60 different proteins had changed. These changes were linked to how the body handles energy, repairs damage, fights infection, and responds to stress. Some of the changes were also connected to processes that can affect cancer risk and inflammation.
This study shows that fighting large urban fires can quickly affect firefighters’ bodies at a molecular level, even within days. Researchers hope this information will help protect firefighters’ health in the future.
This study comprised of 100 male Tucson firefighters (19 Hispanic and 81 non‑Hispanic) compared their urine chemical profiles before and a few hours after fighting fires, using advanced metabolomics methods. The researchers found hundreds of urinary chemical differences between Hispanic and non‑Hispanic firefighters, especially in substances related to galactose (a type of sugar) and tryptophan (an amino acid) metabolism pathways. These metabolic differences were consistent both before and after fire exposure, meaning they weren’t caused by the firefighting event itself. The altered patterns suggest that dietary or environmental factors tied to ethnicity may help explain why Hispanic firefighters seem to face higher risks for certain cancers than non‑Hispanic firefighters
Evaluating changes in firefighter urinary metabolomes after structural fires. (Furlong et al., 2023)
This study examined how firefighting affects firefighters' urine composition, focusing on changes that might relate to increased cancer risks. Researchers analyzed urine samples from 100 male firefighters before and after responding to fires. They found significant changes in certain metabolites, including amino acids and substances linked to kidney function and hormone activity. These alterations suggest that exposure to fire-related chemicals may impact metabolic pathways associated with cancer development. The study highlights the need for further research to understand how firefighting influences cancer risk and to develop strategies to protect firefighters' health.
This study investigated firefighters' exposure to harmful chemicals during firefighting activities using the PAH CALUX bioassay, a test that measures the presence of toxic compounds. Researchers collected skin wipe samples from firefighters before and after controlled fires and found increased levels of polycyclic aromatic hydrocarbons (PAHs) on the neck and calf areas post-fire. Additionally, using baby wipes to clean the face and neck during rehabilitation helped reduce PAH levels. These findings highlight the importance of proper decontamination practices to minimize firefighters' exposure to toxic substances
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Evaluation of interventions to reduce firefighter exposures. (Burgess et al., 2020)
This study evaluated methods to reduce firefighters' exposure to harmful substances during fire responses. Researchers implemented several interventions, including engineers using self-contained breathing apparatus (SCBA) during operations, washing down entry teams after firefighting, isolating contaminated equipment, and ensuring personnel showered and cleaned their gear upon returning to the station. The results showed significant reductions in harmful chemical levels in engineers and firefighters, indicating these measures effectively decrease exposure risks. However, the study found no significant changes for captains, suggesting their exposure sources may differ. Additionally, the use of infrared saunas after fire responses showed potential in reducing chemical levels, but further research is needed to confirm its effectiveness.
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A study of nearly 570 U.S. volunteer firefighters from 41 departments assessed associations between cardiorespiratory fitness (CRF) and both firefighter-level (e.g., years of service, firefighting calls, and firefighter rank) and department-level (e.g., department characteristics and fitness infrastructure). Findings included that 80% of the enrolled firefighters did not meet the recommended CRF level, which is important for safely doing firefighting work. The findings also included that less than 60% of the fire departments offered routine physical exams, and only about 40% offered other fitness resources. These findings highlight individual and structural challenges for physical fitness in the volunteer fire service, underscoring the need for targeted fitness support to protect firefighter health and community safety.
This study looked at volunteer firefighters in the U.S. to find out how many have personal habits that raise their cancer risk. The researchers found that compared to career firefighters, a higher proportion of volunteer firefighters reported health behaviors linked to cancers — like tobacco use, being overweight, lower levels of physical activity, and being overweight or obese. The findings suggest that besides the known risks of exposure to smoke and chemicals in firefighting, lifestyle factors may also play a big role in cancer risk. The findings of this study support the need to provide volunteer firefighters with overall and targeted health promotion and cancer prevention programs.
This study examined volunteer firefighters' perspectives on firefighter- and department-level barriers and promoters of physical activity and fitness. Through interviews with 28 volunteers across different experience levels, it identified five key themes: the importance of fitness for health and job performance; time constraints and availability; departmental responsibility to support fitness; use of training drills as functional exercise; and existing department-level fitness initiatives. While views varied by years of service, overall participants agreed that embedding fitness discussions into meetings and training—and appointing fitness advocates within departments—could help overcome barriers and foster physical activity and fitness among volunteer firefighters.
This study looked at colon and prostate cancer screening among volunteer firefighters in the U.S., who make up two-thirds of the fire service. The research found that the screening rates for colon and prostate cancer were about 52% and 49%, respectively, for those eligible based on national guidelines. Older firefighters and those with some college education were more likely to get screened, while fire service experience and cancer risk perception were not linked to screening rates. The study highlights gaps in cancer prevention efforts for volunteer firefighters and suggests that increased education and screening opportunities from fire departments, healthcare professionals, and public health groups could improve cancer prevention in this group.
This study examined skin cancer screening among U.S. volunteer firefighters, a group at higher risk for melanoma. It found that only 26% of volunteer firefighters received skin cancer screenings. Firefighters who used sunscreen, perceived their skin as likely to burn, were older, had some college education, or had a family history of skin cancer were more likely to be screened. Additionally, those with more firefighting experience were more likely to undergo screening. The study highlights gaps in skin cancer prevention within the volunteer fire service and suggests that increased focus on prevention and screening practices could help improve protection for these firefighters.
This study examined the levels of per- and polyfluoroalkyl substances (PFAS) in the blood of members of a suburban U.S. volunteer fire department. PFAS are synthetic chemicals used in various products, including firefighting foams, and have been linked to health problems. The study found that certain PFAS, such as perfluorododecanoic acid (PFDoA), were detected more frequently and at higher levels in firefighters compared to the general population. Additionally, the amount of PFDoA and perfluorodecanoic acid (PFDA) in the blood was higher in firefighters with more years of service. These results suggest that volunteer firefighters may be exposed to PFAS through their work, highlighting the need for further research and protective measures to reduce exposure.
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Differential Metabolic Profiles by Training Fire Exposure in Female Firefighters (Liu, et al., 2026)
Female firefighters have higher risks for certain cancers and reproductive health problems, but it is not clear how fire exposure affects the body at a chemical level. This study looked at changes in metabolites in urine before and after live-fire training to better understand how training fires impact the body. Researchers compared pre- and post-fire samples while accounting for age and background factors. After training fires, many metabolites changed, showing that fire exposure affects normal body processes. The biggest changes were linked to metabolic pathways that are important for cell membranes and energy use. These pathways are also involved in inflammation, oxidative stress, and cell damage. These changes may help explain how repeated fire exposure could increase long-term health risks. Understanding these effects can support better training practices and firefighter health protections.
Examination of Stress Among Recruit and Incumbent Women Firefighters (Hollerbach et al., 2024)
This study examines the mental health challenges faced by women firefighters, highlighting issues like anxiety, depression, PTSD, and workplace discrimination. It found that while new recruits were more likely to report anxiety, experienced firefighters faced higher rates of PTSD and were more likely to experience sex discrimination and harassment. Those with higher stress levels also reported worse mental health and job satisfaction. The study stresses the need for a comprehensive approach to support women in the fire service, involving fire departments, mental health professionals, and advocacy groups, to address these mental health concerns and improve workplace conditions.
This study examined the relationship between mental health conditions and ovarian reserve in female firefighters. Researchers analyzed data from 372 participants, focusing on self-reported diagnoses of depression, anxiety, and post-traumatic stress disorder (PTSD), and measured their anti-Müllerian hormone (AMH) levels, an indicator of ovarian reserve. The findings revealed that women with anxiety had AMH levels 33% lower, and those with PTSD had levels 66% lower than those without these conditions. No significant association was found between depression and AMH levels.
Firefighter occupational factors and the risk of preterm birth: results from a survey of women firefighters in the USA. (Jung et al., 2023) (FFCCS Affiliated Study)
Anti-Müllerian hormone levels among female firefighters. (Davidson et al., 2022) (FFCCS Affiliated Study)
This study examined ovarian reserve in female firefighters by measuring anti-Müllerian hormone (AMH) levels, a marker of fertility. The research found that female firefighters had, on average, 33% lower AMH levels compared to non-firefighting women, suggesting potential occupational impacts on reproductive health. However, the study did not find a clear link between the number of years in firefighting and AMH levels. These findings highlight the need for further research to understand how firefighting may affect fertility in women.
Occupational factors and miscarriages in the US fire service: a cross-sectional analysis of women firefighters (Jung et al, 2021) (FFCCS Affiliated Study)
This study examined the risk of miscarriage among women firefighters compared to non-firefighters and explored occupational factors that may contribute to this risk. Using data from the Health and Wellness of Women Firefighters Study, the researchers found that female firefighters had a miscarriage rate 2.33 times higher than U.S. nurses. Volunteer firefighters were found to have a greater risk of miscarriage, with those in wildland or wildland-urban-interface roles having the highest risk. The study suggests that role and employment type within the fire service may influence the risk of miscarriage, and further research is needed to better understand these associations and inform policies to protect women's health in the fire service.
This study explored the health concerns of female firefighters. Through focus group discussions with 49 female firefighters, researchers identified two main themes: exposure to hazardous materials and women's health issues, including cancer, pregnancy, and breastfeeding challenges. The participants expressed a need for more resources and guidelines tailored to their specific health and safety needs. These findings highlight the importance of addressing the occupational health concerns of female firefighters to ensure their well-being.
Injury correlates among a national sample of women in the US fire service. (Hollerbach et al., 2020) (FFCCS Affiliated Study)
This study examines occupational injuries among career women firefighters, revealing that nearly a third (31.7%) reported at least one injury in the past year, with dislocations, sprains, and strains being the most common. Factors like race, health, exercise habits, mental health, and job dissatisfaction were linked to higher injury rates. Almost 43% of injuries caused missed work, and 25% of women experienced chronic injuries. The findings highlight the need for strategies to reduce injuries and better protect women in the fire service.
Maternal and child health among female firefighters in the US. (Jahnke et al., 2018) (FFCCS Affiliated Study)
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Firefighters are exposed to many hazardous chemicals and face an increased risk of cancer. This study compared the health impacts of two types of fires: Wildland-Urban Interface (WUI) fires, which burn both vegetation and structures, and Municipal Structure Fires (MSF). This study profiled metabolites in urine samples from firefighters before and after firefighting to see how their metabolic profiles changed. A metabolic profile is like a chemical snapshot of the body. It measures small molecules (metabolites) in a fluid, like urine, which reflects how the body's cells are working. Changes in these metabolites can show how the body is responding to stress, toxins, or physical exertion. The study found that both WUI fires and MSF caused significant changes in firefighters' metabolic profiles, indicating the body was under stress. MSF caused a larger number of metabolic changes (652 metabolites) compared to WUI fires (176 metabolites), suggesting a potentially broader biological impact. Both fire types disrupted processes related to energy production and amino acid metabolism, which are also seen in cancer development, highlighting a potential link between fire exposure and increased cancer risk.
This study looked at the health impacts of wildland-urban interface (WUI) firefighting, which happens when firefighters work in areas where forests and human development meet. These firefighters are exposed to dangerous smoke, burning materials, and toxic chemicals without always having proper protective gear. Since fires at the WUI can last a long time—days to weeks—the researchers wanted to see how this type of exposure might affect firefighters’ bodies, specifically by looking at changes in their genes. The study focused on epigenetics, which are modifications on top of DNA that influence gene expression without altering the underlying DNA code. Specifically, they looked at microRNAs (small molecules that turn off certain genes) and DNA methylation (a process that can turn genes on or off). The researchers took blood samples from 99 firefighters in Southern California at enrollment and again 10 months later. Between the baseline and follow-up, most of the firefighters had responded to at least one WUI fire. They found that 50 different microRNAs showed noticeable changes at the follow-up, indicating that exposures from WUI fires could alter how some genes are regulated. One of the microRNAs, hsa-miR-518c-3p, with a function known to protect against tumors, was associated with responding to WUI fires. However, the study did not find major changes in DNA methylation over time. In conclusion, the exposure to WUI fires seemed to change how some microRNAs were expressed but did not have a strong effect on DNA methylation. We do not know if there changes in gene regulation will contribute to adverse health outcomes later on.
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This article describes the Fire Fighter Cancer Cohort Study, outlining how researchers track firefighters over time to study their risk of developing cancer and related health conditions due to their work. It explains how the study collects detailed data—such as occupational history, exposures, biological samples, and health information—from both incumbent and new firefighters. The study aims to identify patterns in cancer development and potential links to firefighting exposures, helping scientists understand long-term risks and inform prevention strategies. The goal is to build a reliable foundation for reducing health hazards within the firefighting community.
In collaboration with fire service leadership in Arizona, the Firefighter Collaborative Research Project (FCRP) was established to evaluate the effectiveness of 3 interventions in a randomized controlled trial design to reduce serum PFAS levels, reduce cancer and cardiovascular risk, and improve overall health and wellness in US firefighters. This article describes the study protocol.
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This study looked at volunteer firefighters in the U.S. to find out how many have personal habits that raise their cancer risk. The researchers found that compared to career firefighters, a higher proportion of volunteer firefighters reported health behaviors linked to cancers — like tobacco use, being overweight, lower levels of physical activity, and being overweight or obese. The findings suggest that besides the known risks of exposure to smoke and chemicals in firefighting, lifestyle factors may also play a big role in cancer risk. The findings of this study support the need to provide volunteer firefighters with overall and targeted health promotion and cancer prevention programs.
This study examined volunteer firefighters' perspectives on firefighter- and department-level barriers and promoters of physical activity and fitness. Through interviews with 28 volunteers across different experience levels, it identified five key themes: the importance of fitness for health and job performance; time constraints and availability; departmental responsibility to support fitness; use of training drills as functional exercise; and existing department-level fitness initiatives. While views varied by years of service, overall participants agreed that embedding fitness discussions into meetings and training—and appointing fitness advocates within departments—could help overcome barriers and foster physical activity and fitness among volunteer firefighters.
This study examined the relationship between mental health conditions and ovarian reserve in female firefighters. Researchers analyzed data from 372 participants, focusing on self-reported diagnoses of depression, anxiety, and post-traumatic stress disorder (PTSD), and measured their anti-Müllerian hormone (AMH) levels, an indicator of ovarian reserve. The findings revealed that women with anxiety had AMH levels 33% lower, and those with PTSD had levels 66% lower than those without these conditions. No significant association was found between depression and AMH levels.
Examination of Stress Among Recruit and Incumbent Women Firefighters. (Hollerbach et al., 2024)
This study examines the mental health challenges faced by women firefighters, highlighting issues like anxiety, depression, PTSD, and workplace discrimination. It found that while new recruits were more likely to report anxiety, experienced firefighters faced higher rates of PTSD and were more likely to experience sex discrimination and harassment. Those with higher stress levels also reported worse mental health and job satisfaction. The study stresses the need for a comprehensive approach to support women in the fire service, involving fire departments, mental health professionals, and advocacy groups, to address these mental health concerns and improve workplace conditions.
This study looked at colon and prostate cancer screening among volunteer firefighters in the U.S., who make up two-thirds of the fire service. The research found that the screening rates for colon and prostate cancer were about 52% and 49%, respectively, for those eligible based on national guidelines. Older firefighters and those with some college education were more likely to get screened, while fire service experience and cancer risk perception were not linked to screening rates. The study highlights gaps in cancer prevention efforts for volunteer firefighters and suggests that increased education and screening opportunities from fire departments, healthcare professionals, and public health groups could improve cancer prevention in this group.
This study compared serum PFAS (per- and polyfluoroalkyl substances) concentrations between incumbent and recruit firefighters and tracked changes over time in the recruit firefighters. It found that incumbent firefighters had lower levels of certain PFAS, like n-PFOA and PFNA, compared to recruits. Among recruits, most PFAS levels decreased over time, and no significant connection was found between fireground exposure and change in PFAS concentrations over time.
This study explored the connection between firefighting, PFAS exposure, and DNA methylation related to prostate cancer risk. Firefighters have a higher rate of prostate cancer compared to the general population, possibly due to occupational exposure to numerous toxicants including PFAS. DNA methylation is a regulator that turns genes on and off; its normal patterns can be disrupted by exposures and cumulative changes can contribute to development of diseases including cancers. In this study, we analyzed DNA methylation at specific genomic sites previously linked to prostate cancer, in 444 male firefighters. Results showed that firefighting experience was associated with changes in DNA methylation at several sites, but limited links were found between PFAS specifically and methylation at the sites measured. The findings suggest that cumulative exposures from firefighting may influence DNA methylation in prostate cancer risk areas.
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Firefighter occupational factors and the risk of preterm birth: results from a survey of women firefighters in the USA. (Jung et al., 2023) (FFCCS Affiliated Study)
This study examined the risk of miscarriage among women firefighters compared to non-firefighters and explored occupational factors that may contribute to this risk. Using data from the Health and Wellness of Women Firefighters Study, the researchers found that female firefighters had a miscarriage rate 2.33 times higher than U.S. nurses. Volunteer firefighters were found to have a greater risk of miscarriage, with those in wildland or wildland-urban-interface roles having the highest risk. The study suggests that role and employment type within the fire service may influence the risk of miscarriage, and further research is needed to better understand these associations and inform policies to protect women's health in the fire service.
This study examined how firefighting affects firefighters' urine composition, focusing on changes that might relate to increased cancer risks. Researchers analyzed urine samples from 100 male firefighters before and after responding to fires. They found significant changes in certain metabolites, including amino acids and substances linked to kidney function and hormone activity. These alterations suggest that exposure to fire-related chemicals may impact metabolic pathways associated with cancer development. The study highlights the need for further research to understand how firefighting influences cancer risk and to develop strategies to protect firefighters' health.
This study explored the relationship between epigenetic age acceleration (EAA) and microRNAs (miRNAs), which could serve as biomarkers for health, especially for aging and certain diseases. EAA is the difference between a person's biological age (as measured by epigenetic clocks) and their chronological age. The study analyzed DNA methylation and miRNA profiles from 332 firefighters, identifying 183 miRNAs associated with EAA. These miRNAs were linked to various aging-related conditions, such as metabolic and cardiovascular diseases, and several cancers. The research found that different epigenetic clocks, were associated with distinct miRNAs, with GrimAge and Horvath clocks showing stronger connections to disease-related pathways. The findings suggest that understanding the role of miRNAs in EAA could offer insights into the molecular causes of aging and related diseases.
This study examined skin cancer screening among U.S. volunteer firefighters, a group at higher risk for melanoma. It found that only 26% of volunteer firefighters received skin cancer screenings. Firefighters who used sunscreen, perceived their skin as likely to burn, were older, had some college education, or had a family history of skin cancer were more likely to be screened. Additionally, those with more firefighting experience were more likely to undergo screening. The study highlights gaps in skin cancer prevention within the volunteer fire service and suggests that increased focus on prevention and screening practices could help improve protection for these firefighters.
This study examined the relationship between years of service and epigenetic aging among U.S. firefighters. Epigenetic age, which reflects biological aging, was assessed using DNA methylation markers in blood samples from 150 firefighters. The results indicated that longer service was associated with accelerated epigenetic aging, suggesting that the demanding nature of firefighting may contribute to faster biological aging. These findings highlight the importance of reducing firefighters’ occupational exposures and the need to identify treatments to reduce epigenetic age among firefighters.
This study examined the levels of per- and polyfluoroalkyl substances (PFAS) in the blood of firefighters from four U.S. fire departments. PFAS are man-made chemicals found in various products, including firefighting foams, and are known to persist in the environment and human body. The research revealed that firefighters had higher concentrations of certain PFAS compared to the general population, suggesting occupational exposure as a contributing factor. These findings highlight the need for further investigation into PFAS exposure sources and potential health effects among firefighters.
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Anti-Müllerian hormone levels among female firefighters. (Davidson et al., 2022)
This study examined ovarian reserve in female firefighters by measuring anti-Müllerian hormone (AMH) levels, a marker of fertility. The research found that female firefighters had, on average, 33% lower AMH levels compared to non-firefighting women, suggesting potential occupational impacts on reproductive health. However, the study did not find a clear link between the number of years in firefighting and AMH levels. These findings highlight the need for further research to understand how firefighting may affect fertility in women.
Repeat measures of DNA methylation in an inception cohort of firefighters. (Goodrich et al., 2022)
This study investigated how exposure to firefighting activities might affect DNA methylation, a gene regulator, of firefighters over time. Firefighters face a higher risk of developing cancers and other health issues due to the hazardous environments they work in, which includes exposures to smoke and chemicals. One way these hazards might influence health is through changes in DNA methylation, which is a process that can turn genes on or off without altering the DNA code itself. The researchers looked at firefighters' DNA methylation at two points in time: before they started live fire training and again after they had worked for a period of 20 to 37 months. They wanted to see if their DNA methylation patterns changed after they began working as firefighters and if these changes were related to the number of fires they responded to. The study found that DNA methylation patterns did change at many genes, which might help explain how firefighting exposures can alter processes in the body that may eventually contribute to health problems like cancer. This research helps us understand how the body responds to firefighter exposures and provides clues for preventing health issues in the future.
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Maternal and child health among female firefighters in the US. (Jahnke et al., 2018) (FFCCS Affiliated Study)
Injury correlates among a national sample of women in the US fire service. (Hollerbach et al., 2020) (FFCCS Affiliated Study)
This study examines occupational injuries among career women firefighters, revealing that nearly a third (31.7%) reported at least one injury in the past year, with dislocations, sprains, and strains being the most common. Factors like race, health, exercise habits, mental health, and job dissatisfaction were linked to higher injury rates. Almost 43% of injuries caused missed work, and 25% of women experienced chronic injuries. The findings highlight the need for strategies to reduce injuries and better protect women in the fire service.
Occupational factors and miscarriages in the US fire service: a cross-sectional analysis of women firefighters (Jung et al, 2021) (FFCCS Affiliated Study)
This study examined the risk of miscarriage among women firefighters compared to non-firefighters and explored occupational factors that may contribute to this risk. Using data from the Health and Wellness of Women Firefighters Study, the researchers found that female firefighters had a miscarriage rate 2.33 times higher than U.S. nurses. Volunteer firefighters were found to have a greater risk of miscarriage, with those in wildland or wildland-urban-interface roles having the highest risk. The study suggests that role and employment type within the fire service may influence the risk of miscarriage, and further research is needed to better understand these associations and inform policies to protect women's health in the fire service.
Anti-Müllerian hormone levels among female firefighters. (Davidson et al., 2022) (FFCCS Affiliated Study)
This study examined ovarian reserve in female firefighters by measuring anti-Müllerian hormone (AMH) levels, a marker of fertility. The research found that female firefighters had, on average, 33% lower AMH levels compared to non-firefighting women, suggesting potential occupational impacts on reproductive health. However, the study did not find a clear link between the number of years in firefighting and AMH levels. These findings highlight the need for further research to understand how firefighting may affect fertility in women.
This study explored the health concerns of female firefighters, focusing on their perceptions of cancer risks and occupational hazards. Through focus group discussions with 49 female firefighters, researchers identified two main themes: exposure to hazardous materials and women's health issues, including cancer, pregnancy, and breastfeeding challenges. The participants expressed a need for more resources and guidelines tailored to their specific health and safety needs. These findings highlight the importance of addressing the unique occupational health concerns of female firefighters to ensure their well-being.
This study explored how firefighters’ exposure to toxic chemicals, specifically per- and polyfluoroalkyl substances (PFAS), might affect their health at a molecular level. PFAS are chemicals commonly found in firefighting foam and equipment and consumer products. Often called ‘forever chemicals’, PFAS do not break down easily. PFAS accumulate in the body where they can adversely affect health. The researchers measured epigenetic marks – DNA methylation – which regulates how genes are turned on and off. They used the DNA methylation data to approximate biological age (called “epigenetic age”) and also to assess the status of all genes. The study found that firefighters with greater PFAS levels in their blood had greater epigenetic age –meaning their biological age looks older than their true age. PFAS levels were also linked to differences in DNA methylation patterns at specific genes, including genes linked to cancers and immune function. These molecular findings could help explain why people exposed to PFAS, over time, have a higher risk of developing health issues, including cancer and other chronic diseases. The study highlights potential biological processes behind the long-term health impacts of PFAS.
Longitudinal evaluation of whole blood miRNA expression in firefighters. (Jung et al., 2021)
This study investigated whether changes in microRNA (miRNA) expression in firefighters are linked to occupational exposures. The researchers analyzed whole blood miRNA from 52 new recruits before and 20-37 months after live-fire training. They found that certain miRNAs were associated with employment duration, cumulative fire exposure, and time since the most recent fire. Specifically, tumor-suppressive miRNAs tended to decrease, while oncogenic miRNAs increased with exposure. These findings suggest that changes in miRNA expression could be a potential biomarker for fire-related cancer risk, providing insight into the molecular mechanisms behind increased cancer risk in firefighters.
This study examined the levels of per- and polyfluoroalkyl substances (PFAS) in the blood of members of a suburban U.S. volunteer fire department. PFAS are synthetic chemicals used in various products, including firefighting foams, and have been linked to health problems. The study found that certain PFAS, such as perfluorododecanoic acid (PFDoA), were detected more frequently and at higher levels in firefighters compared to the general population. Additionally, the amount of PFDoA and perfluorodecanoic acid (PFDA) in the blood was higher in firefighters with more years of service. These results suggest that volunteer firefighters may be exposed to PFAS through their work, highlighting the need for further research and protective measures to reduce exposure.
Firefighters are at increased risk for multiple cancers. One major goal of the FFCCS is to identify exposures that are contributing to this risk and the biological mechanisms that they are working through. Among the general population and firefighters specifically, risks for some cancers vary according to race and ethnicity. The exposures and biological differences that contribute to these differences are not known. DNA methylation is one process in the body that controls whether genes or turned on or off. Importantly, DNA methylation is responsive to exposures, can differ by race/ethnicity, and widespread changes to DNA methylation are part of the development of cancers. Because of this, DNA methylation has the potential to serve as a marker of the impact of exposures and a predictor of disease risk. Researchers profiled DNA methylation in blood samples from Hispanic firefighters and firefighters from non-Hispanic backgrounds working in the same departments. The study found that DNA methylation patterns were different between firefighters from the two ethnicity groups. Based on the design of our study, we do not yet know whether these genes directly contribute to cancer risks in Hispanic firefighters. These findings could help us better understand how ethnicity and occupation may influence health risks and lead to more targeted health interventions that will protect all firefighters.
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Injury correlates among a national sample of women in the US fire service. (Hollerbach et al., 2020) (FFCCS Affiliated Study)
This study examines occupational injuries among career women firefighters, revealing that nearly a third (31.7%) reported at least one injury in the past year, with dislocations, sprains, and strains being the most common. Factors like race, health, exercise habits, mental health, and job dissatisfaction were linked to higher injury rates. Almost 43% of injuries caused missed work, and 25% of women experienced chronic injuries. The findings highlight the need for strategies to reduce injuries and better protect women in the fire service.
Evaluation of interventions to reduce firefighter exposures. (Burgess et al., 2020)
This study evaluated methods to reduce firefighters' exposure to harmful substances during fire responses. Researchers implemented several interventions, including engineers using self-contained breathing apparatus (SCBA) during operations, washing down entry teams after firefighting, isolating contaminated equipment, and ensuring personnel showered and cleaned their gear upon returning to the station. The results showed significant reductions in harmful chemical levels in engineers and firefighters, indicating these measures effectively decrease exposure risks. However, the study found no significant changes for captains, suggesting their exposure sources may differ. Additionally, the use of infrared saunas after fire responses showed potential in reducing chemical levels, but further research is needed to confirm its effectiveness.
This study investigated firefighters' exposure to harmful chemicals during firefighting activities using the PAH CALUX bioassay, a test that measures the presence of toxic compounds. Researchers collected skin wipe samples from firefighters before and after controlled fires and found increased levels of polycyclic aromatic hydrocarbons (PAHs) on the neck and calf areas post-fire. Additionally, using baby wipes to clean the face and neck during rehabilitation helped reduce PAH levels. These findings highlight the importance of proper decontamination practices to minimize firefighters' exposure to toxic substances.
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DNA methylation among firefighters. (Zhou et al., 2019)
This study investigated DNA methylation patterns in firefighters to understand potential links to increased cancer risk. Researchers analyzed blood samples from 45 incumbent firefighters and 41 new recruits, identifying specific DNA methylation changes associated with years of service. Additional analyses revealed that these changes were related to cancer-related pathways, such as p53 signaling. These findings suggest that occupational exposures in firefighting may lead to epigenetic modifications contributing to elevated cancer risk, highlighting the importance of monitoring and mitigating such exposures to protect firefighters' health.
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Maternal and child health among female firefighters in the US. (Jahnke et al., 2018)
MicroRNA Changes in Firefighters. (Jeong et al., 2018)
This study compared microRNA (miRNA) expression between incumbent firefighters and new recruits to explore potential mechanisms linking firefighting to increased cancer risk. The study found that nine miRNAs had significantly different expression levels between the two groups. Six of these miRNAs, which were less expressed in incumbent firefighters, are known for their tumor-suppressing properties or association with cancer survival. The remaining three miRNAs, more expressed in incumbent firefighters, are linked to cancer promotion or neurological diseases. These findings suggest that firefighting may lead to epigenetic changes that could increase cancer risk.