Firefighting Duties, Including Putting Out Fires, Associated With High Risk of CHD Death

March 22, 2007

March 22, 2007 (Cambridge, MA) – While burns and smoke inhalation are well-known occupational hazards of fighting fires, less appreciated is the risk of heart disease among men and women working in this dangerous occupation. Now, the results of a new study have helped highlight the specific risk of coronary heart disease that firefighters face in various tasks, with fighting fires and responding to alarms associated with a higher risk of death from coronary heart disease than various nonemergent duties. [ 1]

"What makes this study unique is not that we described the number of deaths that were due to heart disease or even exactly what duties they occurred in," Dr Stefanos Kales (Harvard Medical School, Boston, MA) told heartwire . "Instead, this is a statistical analysis with several different models that allowed us to estimate duty-specific risks. We think we've provided the strongest evidence to date that specific firefighting activities can indeed trigger heart events in susceptible firefighters."

The results of the study are published in the March 22, 2007 issue of the New England Journal of Medicine.

Heart disease accounts for 45% of death among US firefighters

Speaking with heartwire , Kales said that the most frequent cause of death among firefighters is heart disease, a finding that is often underappreciated, especially in light of the risks these men and women undertake with their firefighting duties. Cardiovascular events, largely due to coronary heart disease, have previously been shown to account for 45% of deaths among firefighters on duty, which is significantly higher than the cardiovascular mortality of police officers, emergency workers, or those in the general workforce.

Kales said that while various biologically plausible explanations have been proposed, including smoke and chemical exposure, irregular physical exertion, handling heavy equipment, heat stress, shift work, a high prevalence of cardiovascular risk factors, and emotional stress, previous data from his group suggested that coronary events may be triggered by specific firefighting duties, including putting out fires, responding to an alarm, and physical training. As would be expected, these events usually occur in firefighters with underlying coronary heart disease, he noted.

To confirm the findings from an earlier case-control study [ 2], which showed that coronary events may be triggered by specific firefighting duties, and to further explore duty-specific risks of firefighting, Kales and colleagues performed a study of all deaths of US firefighters between 1994 and 2004, excluding deaths associated with the September 11, 2001 terrorist attacks. Estimates of the proportion of time firefighters spent performing various duties were obtained from a municipal fire department, from 17 large metropolitan fire departments, and from a national database.

Among the most active large metropolitan fire departments, the risk of death from coronary heart disease was 12 times higher for firefighters suppressing fires than the risk of death in performing nonemergent duties. If investigators looked at the national activity levels, the risk of death from coronary disease while putting out fires was more than 100 times that of nonemergent duties. Similarly, responding to alarms, returning from alarms, and physical training were all associated with an increased risk of coronary heart disease death compared with nonemergent duties in all three models.

Risk of death from coronary heart disease among firefighters in emergency duties and training compared with nonemergent duties

Duty Municipal fire department, OR (95% CI) p Large metropolitan fire departments, OR (95% CI) p National data, OR (95% CI) p
Nonemergent duties 1.0   1.0   1.0  
Fire suppression 53 (40–72) <0.001 12.1 (9.0–16.4) <0.001 136 (101–183) <0.001
Alarm response 7.4 (5.1–11) <0.001 2.8 (1.94–4.0) <0.001 14.1 (9.8–20.3) <0.001
Alarm return 5.8 (4.1–8.1) <0.001 2.2 (1.6–3.1) <0.001 10.5 (7.5–14.7) <0.001
Emergency medical services and nonfire duties 1.3 (0.9–2.0) 0.16 0.5 (0.3–0.8) <0.001 2.6 (1.8–3.9) <0.001
Physical training 5.2 (3.6–7.5) <0.001 2.9 (2.0–4.2) <0.001 6.6 (4.6–9.5) <0.001



"Nobody is really sure how much time is spent in certain duties, these are just estimates, and every firefighter is different in terms of how he or she spends his time, and every fire department is probably going to have a wide range," said Kales. "While we can't say what the exact risk is, we presented a fairly wide range of estimates so that we can be quite confident that the risk is increased. . . . Although we can't say that we were surprised by the results, we were struck by how consistent the evidence is."

Kales told heartwire that the promotion of fitness programs and wellness activities, as well as regular physicals aimed at the early treatment of risk factors before cardiovascular-disease onset, should be mandatory. In addition, physicians who care for firefighters should be cognizant of how dangerous certain firefighting activities can be and use that information to be aggressive in risk-factor reduction, he said.

When heart disease is diagnosed in a firefighter, he added, extreme caution should be exercised when returning them to the most strenuous of emergency duties. Kales' group has previously shown that 25% of deaths and 20% of nonfatal retirements were linked to firefighters with underlying disease. "I wouldn't want to say that none of them should ever go back, but a lot of caution of should be exercised and, obviously, every case should be looked at on an individual basis," he said.

Firefighters might begin their careers healthy, but . . .

In an audio supplement to the published study [ 3], Dr Linda Rosenstock (University of California, Los Angeles), who wrote an accompanying editorial with Dr Jorn Olsen (University of California, Los Angeles) [ 4], praised the authors for identifying periods of firefighting where coronary heart disease deaths are clustering.

"To the degree that we understand that and put in prevention programs, we may be able to reduce these deaths to some degree," said Rosenstock. "But we know that most of the people dying from cardiovascular deaths, including firefighters in this study, are dying with underlying cardiovascular disease."

The implications of the findings, she said, are clear. Modifiable risk factors, whether or not they are related to their occupation, should be aggressively treated.

"Firefighters are like others," said Rosenstock. "They might enter the workforce healthy, but they may, because they are not keeping up with an active physical-fitness regimen or because they have other risk-taking behaviors, such as cigarette smoking or being overweight, increase the likelihood that they're going to develop coronary disease. With that increased likelihood comes the setting, the background, to which they are more likely to have a fatal cardiac event triggered by and associated with extreme exertion."

The goal, she added, is to keep firefighters, who usually enter the workforce very healthy, as healthy as possible throughout their working life. Preplacement and annual medical examinations, including clearance for firefighters to wear self-contained breathing apparatuses, the implementation of fitness programs, and annual physical-performance evaluations should be mandatory, said Rosenstock.

  1. Kales SN, Soteriades ES, Christophi CA, Christiani DC. Emergency duties and deaths from heart disease among firefighters in the United States. New Engl J Med 2007; 356:1207-15.

  2. Kales SN, Soteriades ES, Christoudias SG, Christiani DC. Firefighters and on-duty deaths from coronary heart disease: a case control study. Environ Health 2003; 2:14.

  3. Interview with Linda Rosenstock on firefighter's risk of death from cardiovascular causes. Supplement to: Kales SN et al. Emergency duties and deaths from heart disease among firefighters in the United States. New Engl J Med 2007; 356:1207-15.

  4. Rosenstock L, Olsen J. Firefighting and death from cardiovascular causes. New Engl J Med 2007; 356:1261-63.

The complete contents of Heart wire , a professional news service of WebMD, can be found at www.theheart.org, a Web site for cardiovascular healthcare professionals.

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