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O3A.3 Do airway inflammation and airway responsiveness markers at start of apprenticeship predict their evolution during initial training? A longitudinal study

The natural history of airway inflammation and symptoms in occupations at risk of asthma is still not fully understood. We aimed to study the evolution during apprenticeship of inflammation markers, bronchial hyperresponsiveness (BHR) and symptoms in at-risk subgroups as defined from measurements of markers made shortly after the start of training. Respiratory symptoms, FEV1 and airway resistance post-bronchial challenge (MBC) test results, fractional exhaled nitric oxide (FeNO) measurements, and eosinophils in nasal lavage fluid were longitudinally investigated in apprentice bakers, pastry-makers and hairdressers. Four baseline risk groups were defined, based on, (i) a high level of FeNO (NO), (ii) eosinophils>1% (Eosino), (iii) a≥15% decrease in FEV1 during the MBC test (HR), and (iv) a≥50% increase in the resistance (Resist). The statistical analysis relied on mixed models. At baseline, the inflammation markers were related to the MBC markers. There was no evidence to suggest that the baseline risk groups predict a differential evolution of the airway inflammation and bronchial responsiveness markers, or the asthma-like symptoms considered. The baseline risk groups defined from MBC test predicted the levels of MBC markers. Similarly, the baseline risk groups based on eosinophilic inflammation predicted the levels of markers for eosinophilia. Twelve possible new asthma cases were identified, only the HR risk group predicted their occurrence. Among this young population, at-risk groups based on initial high levels of inflammation markers did not experience any worsening during the follow-up. Initial BHR predicted consistently high levels of all markers considered and occurrence of possible asthma. These results have been published in BMC Pulmonary Medicine (Demange et al. BMC Pulm Med. 2018 July 11;18(1):113).