Cancer risk among firefighters

It is known that firefighters are at higher risk for some cancers – but we still know too little about the cause of this increased risk. Through this project, we try to find more of the answers.
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Background & Purpose

In 2022, the International Agency for Research on Cancer (IARC) evaluated cancer risk among firefighters. This profession is now classified as a carcinogen. That is, the exposure firefighters are exposed to in their jobs can contribute to the development of cancer. The conclusion is based on the findings made for mesothelioma and bladder cancer. IARC organized a working group of 25 international experts who evaluated the scientific literature on the topic and reached this conclusion. Project manager Kristina Kjærheim was one of the experts who contributed to the assessment, and articles from our project were included in the material evaluated.

However, we still lack knowledge about the cause of such an elevated risk and how it can best be prevented.

The Cancer Registry of Norway and the National Institute of Occupational Health are working on a project to investigate this question among Norwegian firefighters. The project has two main objectives:

  • To evaluate the association between occupational history and cancer risk among firefighters
  • To evaluate the association between specific exposures and cancer risk

Data basis

The Norwegian Fire Departments Cohort

Through the project, we established a cohort of firefighters and other employees at selected Norwegian fire departments from 1950 onwards. In total, the cohort comprises approximately 4500 employees from fifteen of the largest Norwegian cities/fire services.

For each person in the cohort, we have the name and date of birth, all positions/occupational titles of people who have worked at the fire department, including start and end dates for all employment periods. These personal data are linked to registrations from the Cancer Registry of Norway and the Cause of Death Registry. This means that we have an overview of everyone in the cohort who has received a cancer diagnosis, including the date of diagnosis and type of cancer, and everyone who has died, including date of death and cause of death. In this way, we can investigate both the incidence and mortality of cancer among firefighters and compare this with the rates in the general population.

The Directorate for Civil Protection and Emergency Planning (DSB) has provided us with an overview of the number and type of emergency responses in the municipalities where the fire services are located. By considering this in the context of cancer incidence, we can investigate whether there is a correlation between the number of fires a firefighter has participated in and cancer risk.

From each of the participating fire departments, we have collected information on a wide range of working environment conditions from 1950 onwards. By adding this to the analyses, we can investigate the association between the use of respiratory protection or other protective measures and cancer risk. Information on the number of cars, type of fuel and station architecture allows us to study the association between exposure to diesel exhaust and cancer risk.

We have annual meetings with the scientific reference group for input and discussion about the project. Read more about the reference group meeting here.

The work is carried out in accordance with applicable Norwegian and international data protection regulations and with permission from the Regional Committee for Medical Research Ethics. Read more about privacy at the Cancer Registry. 

We are seeking more fire departments to participate in the Norwegian Fire Departments Cohort!

We are now working to expand the Norwegian Fire Departments Cohort. With a larger cohort, future research will have a better starting point and statistical power to investigate both cancer risk and risk of other chronic illnesses. New research and greater knowledge is fundamental to better prevention of work related cancer and disease among firefighters.

Therefore, we wish to recruit more fire departments to contribute with the registration of current and previous employees for follow-up in this internationally renowned cohort.

If you are interested, please contact the project leader Jo Stenehjem, or the assistant project leader Niki Marjerrison.

Status

The project comprises several studies with different aims, which together contribute to an improved understanding of the association between firefighting and cancer.

One article has been produced describing the development of working conditions and the possible impact on exposure to carcinogenic substances at Norwegian fire departments between 1950 and 2018. Another article has analyzed the risk of different cancers with a known association with carcinogenic exposures that are known to occur through firefighting.

Previous research in the field has shown relatively inconsistent findings. Therefore, we have examined whether this can partly be explained by the fact that some publications have studied the risk of receiving a cancer diagnosis, while others have analyzed the risk of dying from cancer.

We have examined the association between cancer of the urinary tract and indicators of occupational exposures. The focus was particularly on exposure to PAHs (polycyclic hydrocarbons), which have a known association with bladder cancer.

We also have an ongoing sub-study examining prostate cancer among firefighters. The background for the project is that the risk of prostate cancer has generally been elevated in studies of firefighters. However, it is unclear whether this is related to occupational exposures and, if so, which exposures.

It is also possible that some of the increased incidence of prostate cancer observed among firefighters can be attributed to frequent health check-ups and Prostate Specific Antigen (PSA) testing. To elucidate the extent to which such a screening effect may have an impact, we have analyzed of the characteristics of prostate cancer in firefighters compared with prostate cancer among policemen, pilots, military personnel, and the rest of the population. Age at diagnosis, stage at diagnosis and mortality are among the variables included.

We are now continuing our work investigating the association between prostate cancer risk and indicators of firefighters’ occupational exposures, as were used in the study on urinary tract cancer.

Publications

Completed publications: 

  1. Work Conditions and Practices in Norwegian Fire Departments From 1950 Until Today: A Survey on Factors Potentially Influencing Carcinogen Exposure. Jakobsen J, Babigumira R, Danielsen M, Grimsrud TK, Olsen R, Rosting C, Veierød MB, Kjærheim K.Saf Health Work. 2020 Dec;11(4):509-516. Doi: 10.1016/j.shaw.2020.07.004. PMID: 33329918
  2. Early detection of prostate cancer in firefighters: a register-based study of prognostic factors and survival. Jakobsen J, Veierød MB, Grimsrud TK, Fosså SD, Hammarström B, Kjærheim K. Occup Environ Med. 2022 Mar;79(3):200-206. doi: 10.1136/oemed-2021-107622. PMID: 34510005
  3. Cancer incidence in sites potentially related to occupational exposures: 58 years of follow-up of firefighters in the Norwegian Fire Departments Cohort. Marjerrison N, Jakobsen J, Grimsrud TK, Hansen J, Martinsen JI, Nordby KC, Veierød MB, Kjærheim K. Scand J Work Environ Health. 2022 Apr 1;48(3):210-219. doi: 10.5271/sjweh.4009. PMID: 35015085.
  4. Comparison of cancer incidence and mortality in the Norwegian Fire Departments Cohort, 1960-2018. Marjerrison N, Jakobsen J, Demers PA, Grimsrud TK, Hansen J, Martinsen JI, Nordby KC, Veierød MB, Kjærheim K. Occup Environ Med. 2022 May 19;79(11):736-743. doi: 10.1136/oemed-2022-108331. PMID: 35589382
  5. Occupational exposures of firefighting and urinary tract cancer risk among men in the Norwegian Fire Departments Cohort. Marjerrison N, Grimsrud TK, Hansen J, Martinsen JI, Nordby KC, Olsen R, Veierød MB, Kjærheim K. Occup Environ Med. 2023 Nov 23;80(12):659-666. doi: 10.1136/oemed-2023-109003. PMID: 37863650

Planned publications:

  1. Occupational exposures of firefighting and prostate cancer risk among men in the Norwegian Fire Departments Cohort. (….) Status: In progress, March 2024.