Increase in exhaled nitric oxide is associated with bronchial hyperresponsiveness among apprentices.
BACKGROUND
Airway inflammation is a hallmark of asthma. Several studies have validated the use of the fractional concentration of exhaled nitric oxide (Fe(NO)) as a surrogate marker of airway inflammation in asthma.


OBJECTIVE
We examined how the change in Fe(NO) levels, since the beginning of occupational exposure, could be associated with the incidence of bronchial hyperresponsiveness (BHR) among baker, pastry maker, and hairdresser apprentices during their 2-year training.


METHODS
A standardized questionnaire was administered; skin prick tests for common and specific occupational allergens were done; methacholine challenge and measurement of Fe(NO) were performed 6, 12, and 15 months after the first examination.


RESULTS
Of 441 apprentices initially included, 351 completed the study. The increase in Fe(NO), since the beginning of exposure, was associated with the incidence of BHR (odds ratio, 2.00 [95% confidence interval, 1.21-3.32] per unit increase in log parts per billion) both in atopic and nonatopic subjects. The average increase in Fe(NO) was similar in atopic and nonatopic subjects and was unrelated to past or current smoking habits, sex, or training track. Atopy in bakers/pastry makers and sensitization to alkaline persulfates in hairdressers were also independently associated with the incidence of BHR. BHR occurred sooner among bakers/pastry makers than among hairdressers, but its incidence leveled off later.


CONCLUSIONS
Our results suggest that measurement of Fe(NO), a simple and reproducible test, could be useful in the screening of BHR in workers newly exposed to agents known to cause occupational asthma.
Institut National de Santé et de Recherche Médicale U954, School of Medicine, Vandoeuvre-lès-Nancy, France.
Paul
P
Tossa
Christophe
C
Paris
Denis
D
Zmirou-Navier
Valérie
V
Demange
Dovi-Stéphanie
DS
Acouetey
Jean-Pierre
JP
Michaely
Abraham
A
Bohadana
D000293:Adolescent; D001249:Asthma / Q000503:physiopathology; D001505:Beauty Culture; D015415:Biomarkers / Q000097:blood; D001944:Breath Tests / Q000379:methods; D016535:Bronchial Hyperreactivity / Q000175:diagnosis* / Q000453:epidemiology; D016085:Bronchoconstrictor Agents; D045853:Exhalation; D005260:Female; D005500:Follow-Up Studies; D005525:Food-Processing Industry; D006801:Humans; D015994:Incidence; D007249:Inflammation / Q000209:etiology; D019570:Inhalation Exposure / Q000009:adverse effects; D008297:Male; D016210:Methacholine Chloride; D009569:Nitric Oxide / Q000032:analysis / Q000378:metabolism*; D009784:Occupational Diseases / Q000175:diagnosis* / Q000453:epidemiology; D016273:Occupational Exposure / Q000009:adverse effects*; D011795:Surveys and Questionnaires
D015415:Biomarkers; D016085:Bronchoconstrictor Agents; D016210:Methacholine Chloride; D009569:Nitric Oxide