Prevalence and Predictors of Per- and Polyfluoroalkyl Substances (PFAS) Serum Levels among Members of a Suburban US Volunteer Fire Department. (Graber et al., 2021)

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.

Per- and polyfluoroalkyl substances, epigenetic age and DNA methylation: a cross-sectional study of firefighters. Epigenomics. (Goodrich et al., 2021)

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.

Serum per- and polyfluoroalkyl substance concentrations in four municipal US fire departments. (Burgess et al, 2023)

Comparison of Serum Per- and Polyfluoroalkyl Substances Concentrations in Incumbent and Recruit Firefighters and Longitudinal Assessment in Recruits. (Nematollahi et al., 2024)

Firefighting, per- and polyfluoroalkyl substances, and DNA methylation of genes associated with prostate cancer risk. (Quaid et al., 2024)

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.

Per- and polyfluoroalkyl substances (PFAS) and microRNA: An epigenome-wide association study in firefighters (Furlong et al., 2025)

MicroRNA Changes in Firefighters. (Burgess et al., 2018)

DNA methylation among firefighters. (Zhou, 2019)

Differential DNA Methylation by Hispanic Ethnicity Among Firefighters in the United States (Goodrich et al., 2021)

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.

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.

Associations Between Epigenetic Age Acceleration and microRNA Expression Among U.S. Firefighters. (Jung et al., 2023)

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.

Occupational Years of Service and Leukocyte Epigenetic Aging: Relationships in United States Firefighters. (Nwanaji-Enwerem et al., 2023)

Epigenetic Modifications Associated With Wildland–Urban Interface (WUI) Firefighting (Goodrich et al., 2025)'

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.

Evaluating changes in firefighter urinary metabolomes after structural fires. (Furlong et al., 2023)

Assessment of the toxicity of firefighter exposures using the PAH CALUX bioassay. (Beitel et al., 2020)

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.

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.

Prevalence and Predictors of Per- and Polyfluoroalkyl Substances (PFAS) Serum Levels among Members of a Suburban US Volunteer Fire Department. (Graber et al., 2021)

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. 

Firefighter- and Fire Department–Level Barriers and Promoters of Physical Activity and Fitness Among Volunteer Firefighters: A Qualitative Study Using Semistructured Interviews

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.

Prevalence and predictors of colon and prostate cancer screening among volunteer firefighters: The United States Firefighter Cancer Assessment and Prevention Study. (Shah et al., 2024)

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.

Firefighter- and Fire Department–Level Barriers and Promoters of Physical Activity and Fitness Among Volunteer Firefighters: A Qualitative Study Using Semistructured Interviews (Shah et al., 2024)

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.

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)

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)

Perceptions of Work-Related Health and Cancer Risks Among Women Firefighters: A Qualitative Study. (Solle et al., 2021)

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.

Evaluating the Effect of Depression, Anxiety, and Post-Traumatic Stress Disorder on Anti-Müllerian Hormone Levels Among Women Firefighters (Valenti et al., 2024)

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.

Epigenetic Modifications Associated With Wildland–Urban Interface (WUI) Firefighting (Goodrich et al., 2025)

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.

The Fire Fighter Cancer Cohort Study: Protocol for a Longitudinal Occupational Cohort Study (Burgess et. al, 2025)

Interventions to Reduce Serum Per- and Poly-Fluoroalkyl Substances Levels, Improve Cardiovascular Risk Profiles, and Improve Epigenetic Age Acceleration in US Firefighters: Protocol for Randomized Controlled Trial (Conner et al., 2025) (FFCCS Affiliated Study)