BOSTON — Firefighters face a much higher risk of death from heart attack when battling a blaze — up to 100 times the normal rate — and are more likely to be struck even when they're doing less-strenuous tasks, according to a Harvard study to be published Thursday.
Heart attacks — not burns or smoke — have long been known to be the most frequent cause of firefighter deaths on the job. But the Harvard study, published in the New England Journal of Medicine, establishes the strongest link yet between coronary disease and firefighting duties by examining what firefighters were doing when they were stricken.
Looking at firefighter heart attack deaths nationwide over a decade, the researchers found that the risk of heart attack is highest when firefighters are working at a fire scene — with increased odds ranging from 10 to 100 times the normal risk of heart attack. Although firefighters spend only 1 to 5 percent of their time putting out fires, 32 percent of firefighter deaths from heart attacks occur at fire scenes, the study found.
But the chances of a heart attack also are significantly increased when firefighters are responding to an alarm, returning from an alarm, or engaging in physical training, according to the researchers from the Harvard School of Public Health, who studied 449 deaths. (See sidebar: Justice Department denies benefits claims for heart attacks .)
The study does not identify the specific causes of these job-related attacks or whether firefighters have an overall greater risk of dying from heart problems than the rest of the population, but does note the unique hazards of the profession. Not only do firefighters deal with extreme heat and exertion, they also are exposed to toxic substances and psychological stress.
Stress, conditioning seen as factors
The authors hypothesize that the risk of dying from heart disease may increase during fire suppression because of the effects of strenuous exertion on firefighters who have underlying coronary heart disease. Also, many firefighters are overweight and lack adequate physical fitness, which may be contributing risk factors, they said.
"We hope that our study will reinforce efforts in the firefighting community to improve their health and wellness programs," said Stefanos Kales, the study's lead author and assistant professor in the Department of Environmental Health at the Harvard School of Public Health.
A 2005 study by the National Fire Protection Association showed that more than 70 percent of fire departments lacked fitness and health programs. Kales' team has published previous research documenting a high prevalence of obesity among firefighters. The majority of the nation's firefighters — about 75 percent — are volunteers.
Kales also said that the researchers are hopeful that “these striking results will make physicians who care for firefighters … more cognizant of the demanding nature of this occupation and get them to be more aggressive with regard to cardiovascular risk reduction."
Earlier studies looked at heart disease rates to see whether firefighters have a greater lifetime risk of heart death than the general population. But because roughly one-third of firefighters and one-third of the general population in developed countries die of cardiovascular disease, those studies were inconclusive.
Deaths correlated with duties
The Harvard researchers took a different tack: Looking at how much time firefighters spend on various duties. If heart attacks were caused by pre-existing conditions — not by on-the-job activities — then deaths during any firefighting duty would be proportional to the amount of time spent on that duty. But the researchers found more-than-expected deaths during firefighting as well as the other activities.
The team, led by Kales and David Christiani, a professor of occupational medicine and epidemiology in the Departments of Environmental Health and Epidemiology at Harvard, studied all on-duty firefighter deaths from 1994 through 2004, using a memorial database maintained by the U.S. Fire Administration. The researchers excluded deaths resulting from the terrorist attacks of Sept. 11, 2001, as well as those caused by medical conditions other than coronary heart disease. That left them with 449 deaths.
The researchers also estimated the average proportion of time firefighters spend on specific job duties using data from several sources, including 17 large metropolitan fire departments. That is the least-precise information in the study, the researchers said, leading to the wide range of estimates for the increased risk for each activity. Still, even using the most conservative figures, the researchers said, the increased risk is "remarkably high."
Heart attacks fell more firefighters
About 100 firefighters die on the job each year, and heart attacks cause about 45 percent of these deaths, a much higher percentage than for other public safety occupations — 22 percent of the on-the-job deaths among police officers, and 11 percent for emergency medical workers. Overall, heart attacks account for 15 percent of all deaths that occur on the job.
The Harvard study was supported by grants from the National Institute for Occupational Safety and Health and the Massachusetts Public Employees Retirement Administration Commission.
The fire service has begun several campaigns to raise awareness among fire chiefs and firefighters to health issues, including the Heart-Healthy Firefighter Program set up by the National Volunteer Fire Council, and a joint Wellness-Fitness Task Force created by the firefighters union and chiefs association. The National Fallen Firefighters Foundation, which previously focused on the needs of surviving families, also is now involved in prevention.
"From medical evaluations to fitness programs to diet, we are in the process of slowly impacting the incident and fatality numbers," said Deputy Chief Billy Goldfeder of Loveland-Symmes, Ohio, who is vice chairman of the safety, health and survival section of the International Association of Fire Chiefs.
“Firefighters generally love what we do — the longer we can live healthy, the longer we can continue to do the job we love."
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