Firefighting Increases Risk Of Death From Heart Disease New Study Says

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Main Category: Cardiovascular / Cardiology
Also Included In: Rehabilitation / Physical Therapy
Article Date: 22 Mar 2007 - 1:00 PST

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A new study suggests that of the various duties performed by US firefighters, the act of firefighting increases their risk of death from coronary heart disease by up to 100 times compared to non emergency duties.

The study is published in the New England Journal of Medicine (NEJM).

The research team, comprising US and Greek scientists, already knew from previous studies that heart disease accounts for 45 per cent of deaths among US firefighters while they are on duty. What they did in this study was to establish which duties carry the most and the least risk in the daily work of the firefighter.

To establish the incidence of heart disease related deaths, they looked at 11 years of records provided by the Federal Emergency Management Agency of all deaths on duty of firefighters between 1994 and 2004, leaving out those linked to the 2001 September 11 terrorist attacks.

They then estimated the amount of time firefighters spent on different duties by analyzing records from three sources: a municipal fire department, 17 large metropolitan fire departments, and a national database.

Using non emergency duties as the reference category, they then calculated the risks (using odds ratio and 95 per cent confidence intervals) of death from coronary heart disease for a range of specific duties.

The results showed that compared with non emergency duties, some emergency duties and physical training were linked with firefighters having an increased risk of death from coronary heart disease.

The team had conducted an earlier smaller study on retirement due to cardiac events with similar results.

Fire suppression takes up between 1 and 5 per cent of the time that a firefighter spends on the job. But it accounted for 32 per cent of deaths from coronary heart disease and compared with non emergency duties carried 10 to 100 times the risk of death from the disease.

The researchers suggest that the reason is the increased demands that fire suppression places on the firefighter's cardiovascular system. The smoke, the chemicals, carbon monoxide, the physical effort and the psychological stress come together to create an effect that lasts for 24 hours, the duration of the elevated risk period.

However, in discussing the results, they also suggest that the risk of coronary heart disease events during the act of putting out a fire could be higher because many firefighters are not physically fit, have an existing elevated cardiovascular risk, and subclinical or clinical coronary heart disease.

They refer to studies that show new recruits are often overweight and have lower aerobic fitness and this is made worse during the working life of the firefighter because more than 70 per cent of fire departments do not have fitness and health programmes.

Also, most fire departments do not require firefighters to exercise, have medical exams, or be evaluated when they go back to work after major illness.

They say many studies have highlighted the increased cardiovascular disease risk factors for firefighters, linked with lower than expected levels of physical fitness.

They mention two studies of firefighters who became ill or died on duty because of coronary heart disease where around 20 per cent of them had previously been diagnosed with a cardiovascular related condition, while the rest were more likely to be smokers, have high blood pressure or be diabetic compared to the other active firefighters.

Like other studies, this study found that the risk of death from coronary heart disease went up with age for all types of duty, with those over 60 having the highest risk and those older than 20 and younger than 40 having the lowest.

However, unlike other studies, the researchers found that professional and volunteer firefighters had different risk factors for death from coronary heart disease and this varied according to type of duty, but both groups had fire suppression as the highest risk factor.

The researchers also found that physical training significantly increased the risk of death from coronary heart disease. This is consistent with other studies that suggest intense physical activity is a strong trigger, especially among those who are physically inactive.

The idea of a triggering event may also explain why these findings, consistent with other studies, put risk of death from coronary heart disease associated with alarm response and alarm return at roughly five to seven times higher than that associated with non emergency duties.

The researchers also found work that reflects a lower level of exposure to physically demanding emergencies, such as emergency medical service and other non fire emergency responses, was not linked with significant increased risk of death from coronary heart disease, which is consistent with the lower fatality rate from heart disease among emergency medical workers who are not firefighters.

In an editorial accompanying the article, scientists from the School of Public Health at UCLA in Los Angeles pointed out that it was not the stress of putting out fires on its own that was causing the deaths because in the vast majority of cases the firefighter had an existing heart condition. The stress was secondary, they said.

In November last year, scientists at the University of Cincinnati, looking at studies covering 110,000 mostly full time firefighters, showed that they are significantly more likely to develop four different types of cancer than workers in other fields.

They found, for example, that firefighters are twice as likely to develop testicular cancer and have significantly higher rates of non-Hodgkin's lymphoma and prostate cancer than non-firefighters. The researchers also confirmed previous findings that firefighters are at greater risk for multiple myeloma, a type of bone marrow cancer.

"Emergency Duties and Deaths from Heart Disease among Firefighters in the United States."
Stefanos N. Kales, Elpidoforos S. Soteriades, Costas A. Christophi, and David C. Christiani.
NEJM Volume 356:1207-1215.
March 22, 2007, Number 12.

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Written by: Catharine Paddock
Writer: Medical News Today
Copyright: Medical News Today
Not to be reproduced without permission of Medical News Today

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