RT Journal Article
SR Electronic
T1 Airway hyperresponsiveness and risk of chest symptoms in an occupational model
JF Thorax
JO Thorax
FD BMJ Publishing Group Ltd and British Thoracic Society
SP 260
OP 264
DO 10.1136/thx.2005.056333
VO 62
IS 3
A1 K Boutet
A1 J-L Malo
A1 H Ghezzo
A1 D Gautrin
YR 2007
UL http://thorax.bmj.com/content/62/3/260.abstract
AB Background: The clinical outcome of asymptomatic airway hyperresponsiveness (AHR) remains unclear. A study was undertaken to evaluate the incidence of respiratory symptoms in a cohort of asymptomatic subjects with AHR at baseline.Methods: A 3 year prospective study involving methacholine challenge tests and serially administered questionnaires was undertaken in 769 apprentices exposed to high molecular weight allergens. Analyses were performed on 428 initially asymptomatic subjects.Results: Thirty eight subjects (8.9%) were airway hyperresponsive (PC20 ⩽8 mg/ml) and asymptomatic at the start of the study. Forty four apprentices (10.3%) developed two or more respiratory symptoms unrelated to work, 13 (34.2%) in the AHR group and 31 (7.9%) in the non-AHR group (risk ratio (RR) 7.88 (95% CI 2.53 to 24.55) among subjects with AHR). The RR of developing two or more respiratory symptoms increased as the degree of PC20 decreased with a significant trend (p<0.001). In a multivariate analysis, AHR (RR 8.33, 95% CI 2.65 to 26.16) and self-reported rhinitis on exposure to pollen through an interaction with a family history of asthma (RR 6.3, 95% CI 1.29 to 31.89) were associated with the incidence of two or more respiratory symptoms; atopy was not a significant covariate.Conclusion: AHR in asymptomatic subjects is an important determinant for the development of respiratory symptoms outside the workplace among apprentices exposed to high molecular weight allergens in their training environment.