Firefighting and death from cardiovascular causes.

Among the approximately 1.1 million firefighters in the United States (of whom about 70% are volunteers and 30% are paid career personnel), about 100 die each year in the line of duty.1 With the exception of 2001, when 344 firefighters died as a result of the events of September 11 at the World Trade Center in New York City, the number of deaths per year has stayed relatively steady, even though the number of structural fires in the United States has been steadily decreasing. Nearly half of the deaths that occur while firefighters are on duty are related to cardiovascular events, and, in this issue of the Journal, Kales et al.2 describe an innovative approach to improving our understanding of this risk. Their findings shed light on sudden cardiac events and their prevention, not just for this vital and revered profession, but also for those who may encounter some of the same risks at work or elsewhere. Firefighting is a high-hazard job, and the work is at times extremely physically demanding. It involves heavy lifting and maneuvering in sometimes awkward and unstable positions while wearing heavy clothing and protective gear in a hot environment.3 In addition, exposure to carbon monoxide and particulate matter in the air is routine, and there is a highly variable risk of exposure to a broad array of other toxic chemicals generated from the smoke of burning materials. It is not surprising that firefighters face an increased risk of illness and death due to cardiovascular disease during periods of intense physical and even psychological stress at work. However, numerous mortality studies, some of which have shown evidence of an increased risk of some cancers (e.g., brain tumors and leukemia) and nonmalignant respiratory diseases, have not shown any consistent evidence of an increased risk of death from cardiovascular disease.3-5 Why not? First, firefighters as a group quintessentially show a “healthy worker effect.” That is, by the very nature of their generally high levels of fitness and health (mandated for all entry-level career firefighters and sometimes required for volunteers), they would be expected to have a lower risk of death (particularly due to cardiac events) than the general population. And they do — on average, a firefighter’s risk of dying from coronary heart disease is about 90% (standardized mortality ratio, 0.9) that of others in the general population. Thus, firefighters overall may not have an excess risk of dying from heart disease, or if they do, the excess risk is small. There is some suggestion of the latter, since many working industrial populations have an even lower risk of dying from coronary heart disease (standardized mortality ratio, 0.8) than firefighters as compared with the general population. One would expect firefighters to fare at least as well. Second, the overall mortality remains a definitive but crude measure of the relationship between exposure hazards and health, and most importantly, of the benefits of prevention. So, even if firefighters have little or no excess risk of death due to cardiovascular disease, there are reasons to both understand and try to prevent the cardiovascular events that do occur, including those that occur on the job. Kales and colleagues build on the observation that cardiovascular events that occur while firefighters are on duty appear to cluster around specific activities (e.g., fire suppression and emergency response) and on their own earlier case– control study suggesting that specific duties are associated with deaths due to coronary heart disease.6 In this study, they reviewed data on all deaths that occurred while firefighters were on