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Severely obese firefighters: What the data says

When researchers studied severely obese firefighters and its effect on their health and safety, the results were alarming


By Walker S.C. Poston, et al.

Obesity is surprisingly common in the U.S. fire service and a concern for firefighters in other developed nations [1-3]. This high rate of obesity, particularly for U.S. firefighters, results in significantly reduced fitness and readiness.

It also likely contributes to the leading cause of firefighter line-of-duty deaths and sudden cardiac death [4-6]. And obesity has been linked to several other negative occupational outcomes for firefighters such as increased injury risk, lost work days and disability due to injury, cardiovascular disease and sudden cardiac death [4-12].

Even more disturbing, medical scientists have identified a growing problem of severe obesity (an individual with a body mass index of 35kg/m2 or greater) in the fire service, with preliminary data suggesting rates between 9 percent and nearly 11 percent [8,11].

While this appears to be lower than that found for adults in the general U.S. population [13], given the rigors of firefighter duties, it is concerning that one in 10 firefighters in the U.S are in one of the highest obesity categories.

Severe obesity, along with the presence of two comorbid conditions (such as hypertension or sleep apnea), qualifies a firefighter, or any adult, for obesity surgery according to the American Society for Metabolic and Bariatric Surgery. Given the debilitating nature of severe obesity, it undoubtedly interferes with firefighter readiness and increases their risk of negatively occupational outcomes [8-9,11].

Unfortunately, little has been published on the extent of severe obesity in the fire service, the accuracy of BMI for categorizing severe obesity and the health profiles of firefighters experiencing severe obesity. One health risk that firefighters with severe obesity are likely to be particularly vulnerable to is metabolic syndrome.

According to the International Diabetes Federation, metabolic syndrome is a clustering of some of the most hazardous risk factors identified for diabetes, cardiovascular disease and heart attack, all which play a role in sudden cardiac death [14-15]. Individuals with metabolic syndrome are at high risk for poor health and fitness.

Looking at the data
To better understand this situation, here is some data from health assessments of firefighters who participated in five studies.

  1. 480 male career firefighters from departments that did not have wellness programs enrolled in the Fuel-to-Fight (F2F) study [16], a national observational study on firefighter nutrition and health.
  2. 522 male career firefighters in departments with active wellness programs in the same F2F study [16].
  3. 478 male career firefighters in the Firefighter Injury Risk Evaluation study, a prospective evaluation of health behavior risk for injury among firefighters in the central U.S. [1]
  4. 735 male career firefighters in the U.K. [2]
  5. 167 male career firefighters from the Moscow region in the Russian Federation [3].

Assessments with female firefighters are not presented due to their low representation (less than 5 percent) in all of the studies. Details about the methodology for these studies are provided in the studies cited above. There are three important findings worth closer examination.

1. The prevalence of severe obesity is highest in the U.S. fire service.
Figure 1 illustrates the prevalence of severe obesity in the five study samples. Given the debilitating nature of severe obesity, it is difficult to imagine that firefighters with this level of obesity would be able to perform challenging fire suppression tasks.

The high rates of severe obesity found among firefighters is also alarming because medical scientists have convincingly shown that obese firefighters demonstrate much lower aerobic fitness levels when compared to non-obese firefighters [1,17]. In addition, studies also have documented that increasing obesity is associated with worse performance on timed occupational readiness tests for firefighters [18-20].

The fact that approximately 10 percent of operational firefighters (at least in the case of the U.S.) suffer from severe obesity raises the question of whether they are a safety risk to themselves and others by serving in operational firefighting crews.

Figure 1. Prevalence of severe obesity

2. BMI-based assessment is a remarkably accurate method to identify severe obesity.
Some question the validity of BMI-based classification of obesity for firefighters or those in other occupations requiring vigorous physical activity. The greatest concern is that fit and muscular firefighters will be mistakenly categorized as obese.

However, studies comparing BMI-based classification of obesity with waist circumference or measured body fat percentage have shown that the rates of misidentifying a fit and muscular firefighter as obese are fairly low, with rates ranging from 3 to 14 percent (methods for assessing body fat percentage varied in these studies) for body fat percentage and 7 to 10 percent for waist circumference [1,17,21].

We evaluated the number of firefighters in our five datasets who would have been categorized incorrectly by determining how many severely obese firefighters (those with BMI at or greater than 35kg/m2) were misclassified when comparing their BMI to their waist circumferences, using the standard threshold for abdominal obesity of 102cm/40 inches for males [1].

We selected this approach for three reasons.

  • The rates of false positives using the waist circumference method are less variable than those for body fat percentage.
  • Fire departments could easily include waist circumference as a body composition measure, in addition to determining BMI, to potentially correct any misclassifications.
  • Methods for determining body fat percentage vary greatly with respect to the accuracy, equipment costs and training required for personnel to administer the assessment.

In the F2F U.S. Standard Departments, only one of the 53 individuals was misclassified, but the waist circumference was less than 102cm (40 inches). Additionally, there were two firefighters in the FIRE Study Departments out of 46 who also were misclassified.

However, it is notable that all three firefighters' waist circumferences (ranging from 98cm/38.5 inches to 100cm/39.4 inches), while not technically obese, were still in the unhealthy range for males — that is, greater than 94cm/37 inches. There were no misclassifications in the F2F Wellness Departments or among firefighters in the U.K. or R.F. samples.

3. Firefighters with severe obesity exhibit significant risks for metabolic syndrome.
All five of the studies measured one or more metabolic syndrome component, but only the F2F Standard Departments had all components so that the prevalence of the metabolic syndrome could be calculated. Table 1 provides the definition of each metabolic syndrome component and the IDF definition of metabolic syndrome [22].

Table 1. Metabolic syndrome components and overall prevalence in five firefighter samples

As the table shows, the prevalence of the various metabolic syndrome components were greatly elevated for severely obese firefighters [14]. A very large percentage of severely obese firefighters, not surprisingly, were at high risk for central adiposity and high blood pressure.

Also, in the F2F Standard Departments, where all metabolic syndrome components were assessed, more than half (61.4 percent) met the definition of metabolic syndrome. This is a rate comparable to that found among U.S. males over 60 years old [22]. Given the strong link between metabolic syndrome and cardiovascular disease and diabetes [14-15], it is disturbing to see such a high prevalence among severely obese firefighters.

Indeed, the question that really should be posed is whether the fire service is doing a disservice to these firefighters by not seriously addressing the issue of severe obesity among operational firefighters.

There are well-established associations between obesity, particularly severe obesity, and a number of negative health outcome in the general adult population. Obesity results in increased risk for all-cause and cardiovascular mortality, metabolic syndrome, depression, cardiovascular disease and adverse occupational outcomes and health care costs [23-28].

In addition, there is strong evidence that obesity, in particular severe obesity, is associated with a number of negative health and occupational outcomes for firefighters [4-12].

Naming the risk
Firefighters are tactical athletes who work under the most severe environmental conditions while enduring heat stress and having to engage in physiologically taxing activities. Thus, fitness for duty is paramount to their mission success, personal safety and survival.

Therefore, the fire service should consider severe obesity as an important marker of health risk and, at the very least, identify and provide rehabilitation (and perhaps transition out of active firefighting if not successful) to firefighters who reach this level of adiposity.

There have been calls for policies to reducing sudden cardiac death among both entry-level and incumbent firefighters [4-5], but specific criteria for being deemed physically fit to serve have not been established.

Other tactical professions such as the military have set definitive guidelines for fitness requirements and performance (engaging in regular fitness training and annual fitness testing), BMI standards (upper limit of 27.5kg/m2) and estimated body fat percentage guidelines (range of 18 to 26 percent for men and 26 to 35 percent for women depending on age). Those who exceed the upper end of these standards are referred to rehabilitative programs [29].

Many fire departments require new candidates to pass a physical agility test to demonstrate fitness for firefighting and that they can perform critical duties. However, most firefighters will never again have to demonstrate that they are sufficiently fit to perform their duties.

What to do
The military performs annual body composition and fitness tests on all personnel, even those that perform primarily sedentary jobs where fitness and body composition do not likely play any role in actual job performance. They do this because they believe it is important to improve and maintain the health of military service members.

Should any less be expected or done for firefighters? It is puzzling that the fire service does not engage in regular occupational work performance testing other than for new candidates. Does fitness cease to be important after a firefighters starts the job?

It is reasonable to conclude that severe obesity is a good place to start a discussion of fitness standards in the fire service [4-12,23-28]. Is there any compelling argument against the notion that a person with severe obesity is not physically ready to perform the demanding tasks of firefighting?

Unfortunately, wellness programs are still not the norm or required in the U.S. fire service, despite having demonstrated health benefits for firefighters [5,16]. However, even among departments that have wellness programs and access to exercise equipment, many firefighters fail to maintain their fitness and healthy body composition.

Without some form of standards, similar to the requirement for passing the CPAT for entry into the fire service, the problem of obesity and low fitness among firefighters will likely worsen. Screening for obesity requires little cost for departments.

For instance, waist circumference assessment can be carried out with much less training and equipment than other methods for estimating body composition and, along with BMI, will enhance the accuracy of obesity screening and address most firefighters' concerns about incorrect classification.

It's time for the fire service to get serious about fitness and that includes body composition and fitness standards.

About the authors
Walker S.C. Poston, Ph.D., M.P.H., is deputy director of the Institute for Biobehavioral Health Research at the National Development and Research Institutes, Inc. and a senior principal investigator in the Center for Fire, Rescue, and EMS Health Research. Dr. Poston is an occupational epidemiologist whose research focuses on occupational epidemiology and health, firefighter and military health issues, and the etiology, and assessment, and management of obesity and cardiovascular disease. He is a Fellow of the American College of Epidemiology (FACE), a Fellow of The Obesity Society (FTOS) and a decorated U.S. Air Force veteran.

Konstanin Gurevich, M.D., Ph.D., Dr.Sci., is professor of public health and chairholder of UNESCO chair in Healthy Life for Sustainable Development at the Moscow State University of Medicine and Dentistry. He is a physician and scientist with a background in medicine, general pathology, biochemistry, pharmacology and public health. Dr. Gurevich's primary research interests are focused in prevention medicine.

Fehmidah Munir, Ph.D., CPsychol, AFBPsS. is a reader in health psychology in School of Sport, Exercise and Health Sciences at Loughborough University in the United Kingdom. She received her BSc psychology at Sheffield Hallam University and her Ph.D. from the University of Nottingham. Dr. Munir was a lecturer for five years at the Institute of Work, Health & Organisations at the University of Nottingham. Dr. Munir is a chartered health psychologist, Associate Fellow of the British Psychological Society and registered with the Health and Care Professions Council.

Christopher K. Haddock, Ph.D., is director of the Institute for Biobehavioral Health Research at the National Development and Research Institutes, Inc. and a senior principal investigator in the Center for Fire, Rescue, and EMS Health Research. Dr. Haddock's research focus in on health issues among tactical athletes such as individuals in the military, fire service and law enforcement. He is a National Strength and Conditioning Association Certified Personal Trainer, a Fellow of The Obesity Society, an Accredited Professional Statistician and full member of the American Statistical Association. Dr. Haddock also is a decorated U.S. Air Force veteran.

Sara A. Jahnke, Ph.D., is a principal investigator with the Institute for Biobehavioral Health Research at the National Development and Research Institutes, Inc. and the director of the Center for Fire, Rescue, and EMS Health Research. Dr. Jahnke is trained in the behavioral sciences and is very active in fire service health initiatives. She is an active member of the Safety, Health and Survival section of International Association of Fire Chiefs and wrote a white paper for the Third Life Safety Summit of the Everyone Goes Home program from the National Fallen Firefighters Foundation.

Nattinee Jitnarin, Ph.D., is a principal investigator with the Center for Fire, Rescue, and EMS Health Research within the Institute for Biobehavioral Health Research at the National Development and Research Institutes, Inc. Dr. Jitnarin is trained in nutrition, health psychology, qualitative research methods and epidemiology, and currently is the principal investigator of a grant from the American Cancer Society focused on developing an intervention for smokeless tobacco use for firefighters.

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