Respiratory Diseases and the Fire Service - IAFF

22 Chapter 1-2 • Occupational Risks of Chest Disease in Fire Fighters
and indirect (mannitol) airway challenge tests. Asthma was considerably
under-diagnosed in fire fighters. The combination of a structured symptom
questionnaire with a bronchial challenge test identified fire fighters with
asthma. The authors conclude that these tests should routinely be used in
the assessment of active fire fighters and may be of help when evaluating
candidates for this profession. 26
FIRE FIGHTERS AND DISEASES OF THE
RESPIRATORY SYSTEM
Attempts to establish associations between fire fighters and occupational
diseases have yielded conflicting results, reflecting the challenges encountered
in studying this population. Because fire fighters are selected for their abilities
to perform strenuous tasks they should demonstrate a “healthy worker effect.”
The term “healthy worker effect” is used when a population has lower rates of
disease and death than the general population thereby, accidentally masking
exposure-response associations. To control for this, some studies rely on
comparisons of fire fighters to police officers, a group presumed to be similar
in physical abilities and socioeconomic status. Longitudinal dropout (due to
job change or early retirement) may also reduce morbidity and mortality rates.
Fire fighters who experience health problems related to their work may choose
to leave their position, creating a survivor effect of individuals more resistant to
the effects of firefighter exposures. Other issues that may influence morbidity
and mortality rates in fire fighters are differences in exposures, both makeup
and duration, between individuals and between different fire departments.
In fact, the occupational exposures experienced by fire fighters varies greatly,
influenced by the types of fires encountered, job responsibilities, and use of
personal protective equipment. A further complication is that studies rarely
account for non-occupational risk factors such as cigarette smoking due to lack
of data. Finally, mortality studies frequently rely solely on death certificates
even though it is well known that the occupation and cause of death may be
inaccurate. Despite these difficulties, many important observations about the
health of fire fighters have been made.
Overall, fire fighters have repeatedly been shown to have all-cause mortality
rates less than or equal to reference populations. Increased death rates
from non-cancer respiratory disease have not been found when the general
population was used for comparison. To reduce the presumed impact of the
“healthy worker effect”, two studies used police officers for comparison. In
both of these studies, fire fighters had increased mortality from non-cancer
27, 28
respiratory disease.
By definition, mortality studies do not identify the human cost of chronic
debilitating lung disease. Very large exposures to pulmonary toxicants can lead
to permanent lung damage and disability. At 22 months, 9.4% of fire fighters
exposed to hydrochloric acid during a large PVC fire were diagnosed with
asthma and 14.3% were told that they had bronchitis. 14 Asthma or reactive
airways dysfunction has also been shown to occur in fire fighters exposed to
WTC dust. 23, 29 Fire fighters have not been shown to be at an increased risk of
death from lung cancer, but again these studies are also confounded by the
"healthy worker effect" and longitudinal dropout.