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(Vol. 30, Number 3)
Firefighters present more respiratory symptoms in the course of their work than the general population, and are more prone to allergies. So finds a study in the forthcoming issue of the European
Respiratory Journal (ERJ), the scientific publication of the
European Respiratory Society (ERS). Bronchial hyperreactivity also affects firefighters twice as often as the general population.
The cause could be pollutants breathed in during their work.
Firefighters are in the front line for many dangers, and their lungs are bombarded with pollutants and irritants. Although there is increasingly sophisticated protective equipment, such as self-contained breathing apparatus (SCBA), repeated exposure to toxins can be very harmful for their airways.
Studies of American municipal fire brigades have found a rise in respiratory symptoms and a temporary decline in spirometric test performance immediately following firefighting work.
For example, the firefighters who were deployed at the World Trade Centre on September
11, 2001 suffered a reduction in respiratory capacity and persistent bronchial hyperreactivity in proportion to the intensity of their exposure to toxins.
Firefighters increasingly exposed
While there have been several isolated studies, the data on firefighters' respiratory health remain very patchy. Their level of sensitisation to airborne allergens or general degree of susceptibility to allergies (atopy) have not really been explored, although this occupational group, in addition to undertaking strenuous physical work, is increasingly exposed to various toxic products of combustion.
The need for such data inspired David Miedinger and his colleagues, of the respiratory medicine department of Basle University Hospital in Switzerland, to launch the original study published in September's ERJ.

In an extension of the well-known SAPALDIA project (Swiss Study on Air Pollution And
Lung Diseases In Adults), almost all of Basle's professional firefighters (101 out of 107) were studied and compared with a control group of 735 men living in the same area. The subjects had an average age of 41 years and the firefighters had been working in the job for an average of 16 years.
All of the subjects completed a questionnaire and underwent spirometric testing, skin-prick tests for allergies and a methacholine test for non-specific bronchial hyperreactivity.
Symptoms more frequent during work
While the two groups had comparable levels of subjects presenting classical respiratory symptoms, as well as a similar percentage of medically diagnosed asthma (6-8%), a considerably higher proportion of firefighters complained of various symptoms that arose in the course of their work. These included: a runny nose (19% of firefighters compared with
2% of the control group); irritation of the throat (26% compared with 3%); a burning sensation in the eyes (21% compared with 3%); a cough (28% compared with 3%); headache
(25% compared with 3%); and breathlessness (7% compared with 2%).
These findings are somewhat surprising, since firefighters are generally considered to be fitter than the general population and they undergo various medical examinations and physical endurance tests during recruitment and at regular intervals throughout their career.
Miedinger notes in this connection that "the general questionnaires on respiratory symptoms used in epidemiological studies are probably not appropriate for assessing firefighters' respiratory symptoms."
Indeed, in addition to the workplace symptoms reported by firefighters, the ERJ article reveals that 51% of them are atopic, i.e. susceptible to allergies, a much higher proportion than in the control group (32%).
And 16% of firefighters have a positive response to methacholine testing for bronchial hyperreactivity, almost double the 9% seen in the general population.
Pollutants' role
"Firefighters' high level of atopy could be caused by pollutant exposure at the fire station or during fires," the ERJ article's authors comment.
In this context, Miedinger notes that protective devices such as breathing apparatus, recommended for all interventions, are not always used in practice: firefighters tend to leave them off when there are no visible smoke or flames.
Air pollution is known to facilitate allergen sensitisation, in particular by damaging the mucous membranes in the airways, thus allowing allergens to penetrate. This could be one explanation for the higher atopy rates among older firefighters (aged forty to fifty years), who have suffered more exposure to toxic fumes than their younger colleagues.
The authors believe other studies are now needed to clarify the impact of firefighting work on respiratory allergens and bronchial hyperreactivity. The latter condition would need to be confirmed in firefighters with less exposure and in other countries, Miedinger adds.
There is also a need to assess the impact of respiratory problems on performance at work and on rates of early retirement for medical reasons.
Finally, the authors emphasise that "respiratory protection should be more widely used, even when the air appears to be clean."

Title of the original article:
Respiratory symptoms, atopy and bronchial hyperreactivity in professional firefighters