The Evidence

Cancer Studies

Three key studies provide the scientific basis regarding increased cancer risk from the occupation of firefighting: The LeMasters meta‐analysis; a study by the National Institute for Occupational Safety and Health (NIOSH); and a study of fire fighters in Nordic countries provide significant information about cancer risks in firefighters.

The LeMasters meta‐analysis is a widely reviewed report developed by environmental health researchers at the University of Cincinnati. This study, published in 2006, is a comprehensive investigation of cancer risks associated with firefighters using a research technique known as “meta‐analysis.” Meta‐analysis is a quantitative statistical analysis method that pools data from separate but similar experiments or studies. Using meta‐analysis, researchers are able to test the pooled data for statistical significance which is better able to detect increased risk.

LeMasters and her colleagues combined data from 32 studies of firefighters analyzing 20 cancer types. They classified the cancers into three categories: probable, possible, or unlikely. The study identified 10 cancers that have significant increases in firefighters.

• Testicular cancer (102% greater risk)
• Multiple myeloma (53% greater risk)
• Non‐Hodgkin lymphoma (51% greater risk)
• Skin cancer (39% greater risk)
• Prostate cancer (28% greater risk)
• Malignant melanoma (32% greater risk)
• Brain cancer (32% greater risk)
• Rectum (29% greater risk)
• Stomach (22% greater risk)
• Colon cancer (21% greater risk)

Note: The entries in italics are not covered by Arizona’s current fire fighter cancer presumption law.

The NIOSH study examined cancer risks in 29,993 career fire fighters from three large U.S. cities: San Francisco, Chicago, and Philadelphia (Daniels et al., 2013).The study found that firefighters have a 14% increased risk of dying from cancer compared to the general population.

The NIOSH study has several strengths: It includes a large study population. This was a pooled analysis of 30,000 career firefighters from three different geographically diverse cities. It also covered a long study period. Data was collected from 1950 through 2009.

The study found that fire fighters have a statistically significant increased risk of dying from seven different types of cancer compared to the general population:

• Mesothelioma (100% increase)
• Rectum (45% increase)
• Buccal/pharynx (40% increase)
• Esophagus (39% increase)
• Large intestine (31% increase)
• Kidney (29% increase)
• Lung (10% increase)

The Nordic study studied the likelihood of cancer risk in a cohort of 16,422 firefighters from five Nordic countries (Pukkala, et al., 2014). Cancer incidence was assessed by linking national cancer registries to census data on occupations from 1961 – 2005. It found statistically significant increased risk for developing the following cancers:

• Prostate cancer (13% increase overall, though the highest risk was found among firefighters 30-49 years old, who showed a 159% increased risk).
• Malignant melanoma (25% increase)
• Non‐melanoma skin cancer (33% increase)
• Mesothelioma in firefighters over 70 years of age (159% increase)
• Lung adenocarcinoma (29% increased risk)

For more information on the link between cancer and a career as a fire fighter, go here.

Cardiac Studies

While 37 of the 50 U.S. states have cardiac presumption legislation to protect firefighters and peace officers, such a law currently does not exist in Arizona. Heart or cardiovascular disease is the most frequent cause of duty related mortality of firefighters (Heart Disease In The Fire Service, 2013). In addition, for every fatal on-duty cardiac event, there are an estimated 17 non-fatal line of duty heart-related events in the United States (Karter and Molis, 2005).

Guidotti and Brandt-Rauf (1995) conducted an extensive literature review to study disease risk among firefighters to infer magnitude of risk. Based on the criteria for presumption of occupational risk accepted in most worker’s compensation claims, the standard mortality rate (SMR) of 200 is equal to an attributable 100% of expected claims, they concluded that fatal arrhythmia, or myocardial infarction, occurring on or soon after near-maximal stress on the job are likely to be work-related.

Kale et. al. (2003) in study entitled Firefighters and on duty deaths from coronary heart disease: a case control study, confirmed Guidotti’s findings. Moreover, the researchers concludes that other symptoms that generate cardiovascular arousal are caused by work events and are work related.

Kale et al. (2007) followed up this previous research with additional research entitled Emergency duties and deaths from heart disease among firefighters in the United States.

This research focused on several typical duties in the occupation of firefighting: fire suppression, training, alarm response, and strenuous physical activity. In each research question, statistically significant relationships were identified, which linked the occupation with fatal heart attacks. Compared with the odds of death from coronary heart disease during nonemergency duties, the odds were 12.1 to 136 times as high during fire suppression, 2.8 to 14.1 times as high during alarm response, 2.2 to 10.5 times as high during alarm return, and 2.9 to 6.6 times as high during physical training.

The research concluded that “taken together these findings suggest that fatal heart attacks suffered by fire fighters while on duty are work related”.

Numerous studies have determined that strenuous physical activity, emotional stress, and environmental pollutants exacerbate underlying cardiac problems in the general population. Moreover, firefighters demonstrate a sympathetic ‘fight or flight’ type of stress in reaction to emergency alarms (Kuorinka, 1981), have an increase link to cardiac disease due to their shift work and long hours (Steenland, 2000), and are exposed to further occupational threats to their cardiac health from use of personal protective wear and heat stress (Smith et al, 2015).

The NIOSH Alert (2007) explains that over 75% of heart events take place at an incident, during training, or traveling to or from an incident. Furthermore, “These activities are known to produce high heart rates and elevated blood pressures, which can be attributed to alarm response or performing physically demanding tasks” (NIOSH Alert, 2007, p. 14).

Additionally, research findings reported by Kale et. al. (2007) in relation to the circadian patterns of heart disease show a link that differentiates firefighters from the general population. In stark contrast to the general population, where heart events peak in the morning, over two-thirds of line of duty heart deaths occur between the hours of noon and midnight. This timing mirrors the pattern of emergency alarms and dispatches and provides strong support of the link between firefighting and cardiac events.

For more information about a career in firefighting and the increased risk of a cardiac incident, go here.