Early markers of airways inflammation and occupational asthma: rationale, study design and follow-up rates among bakery, pastry and hairdressing apprentices.
BACKGROUND
Occupational asthma is a common type of asthma caused by a specific agent in the workplace. The basic alteration of occupational asthma is airways inflammation. Although most patients with occupational asthma are mature adults, there is evidence that airways inflammation starts soon after inception of exposure, including during apprenticeship. Airways hyper responsiveness to methacholine is a valid surrogate marker of airways inflammation, which has proved useful in occupational epidemiology. But it is time-consuming, requires active subject's cooperation and is not readily feasible. Other non-invasive and potentially more useful tests include the forced oscillation technique, measurement of fraction exhaled nitric oxide, and eosinophils count in nasal lavage fluid.


METHODS
This study aims to investigate early development of airways inflammation and asthma-like symptoms in apprentice bakers, pastry-makers and hairdressers, three populations at risk of occupational asthma whose work-related exposures involve agents of different nature. The objectives are to (i) examine the performance of the non-invasive tests cited above in detecting early airways inflammation that might eventually develop into occupational asthma; and (ii) evaluate whether, and how, constitutional (e.g. atopy) and behavioural (e.g. smoking) risk factors for occupational asthma modulate the effects of allergenic and/or irritative substances involved in these occupations. This paper presents the study rationale and detailed protocol.


CONCLUSIONS
Among 441 volunteers included at the first visit, 354 attended the fourth one. Drop outs were investigated and showed unrelated to the study outcome. Sample size and follow-up participation rates suggest that the data collected in this study will allow it to meet its objectives.
Tossa
Paul
P
INSERM U954, School of Medicine, Vandoeuvre-Les-Nancy, France. Paul.Tossa@nancy.inserm.fr
Bohadana
Abraham
A
Demange
Valérie
V
Wild
Pascal
P
Michaely
Jean-Pierre
JP
Hannhart
Bernard
B
Paris
Christophe
C
Zmirou-Navier
Denis
D
D000293:Adolescent; D000395:Air Pollutants, Occupational / Q000276:immunology / Q000506:poisoning*; D001249:Asthma / Q000175:diagnosis / Q000209:etiology / Q000276:immunology*; D001505:Beauty Culture; D005260:Female; D005500:Follow-Up Studies; D005525:Food-Processing Industry; D006801:Humans; D007249:Inflammation / Q000209:etiology / Q000276:immunology; D018836:Inflammation Mediators / Q000276:immunology*; D019570:Inhalation Exposure / Q000009:adverse effects; D008297:Male; D017817:Nasal Lavage Fluid / Q000166:cytology / Q000276:immunology; D009784:Occupational Diseases / Q000209:etiology / Q000276:immunology*; D016273:Occupational Exposure / Q000009:adverse effects*; D012129:Respiratory Function Tests; D012137:Respiratory System / Q000187:drug effects / Q000276:immunology; D012307:Risk Factors; D012882:Skin Tests; D012907:Smoking
D000395:Air Pollutants, Occupational; D018836:Inflammation Mediators