Incidence of Bronchial Hyperresponsiveness among Apprentices Exposed to Flour Dust and Hairdressing Chemicals and Changes in Exhaled Nitric Oxide

Abstract

ISEE-0063 Background and Objective: The fractional concentration of exhaled nitric oxide (FENO), a simple, non-invasive and reproducible test, has been used as a surrogate marker of airways inflammation in several studies on asthma. It is still unclear, however, how useful FENO is to investigate occupational asthma (OA) or detect bronchial hyperresponsiveness (BHR). Methods: The association between changes in FENO levels since inception of exposure among bakery, pastry-cooking and hairdressing apprentices and the incidence of BHR was studied along their two-year training programme. At months 3, 9, 15 and 18, on average, after start of the programme, a metacholine challenge and measurement of FENO were performed during a medical visit, with completion of a standardized questionnaire and skin prick tests with common and specific occupational allergens. Results: Among 441 apprentices initially included, 351 completed the study. FENO values are influenced by gender (males>females), atopy (atopics>non atopics), smoking (non smokers>smokers). Increase in FENO values since inception of exposure was associated with the incidence of BHR (OR = 2.00 [95%CI = 1.21-3.32] per unit increase in log ppb), both among atopic and non-atopic volunteers, and was unrelated to past or current smoking habits, gender or training track. Incidence of BHR was also associated with atopy among bakers and pastry cooks (OR = 2.37 [1.2-4.7]) and skin sensitization to alkaline persulfaltes among hairdressers ([OR = 4.3 [0.9-21.4]). Conclusion: We conclude that measurement of FENO is a convenient means for early detection of BHR in occupations at risk of asthma. Studies should be undertaken to assess its usefulness as an early marker of non-occupational asthma.