Association entre pollution particulaire et inflammation des bronches : effet modulateur de l'asthme et de l'atopie

The aim of the present study was to investigate, using exhaled nitric oxide (FeNO) as a marker of bronchial inflammation, the inflammatory effects of air-borne particles in children in the general population and to examine the role of asthma and atopy on any observed associations. FeNO was measured in 149 children at school in central Clemont-Ferrand participating in the Six Cities Study. Exposure to particles with a dimension of less than 2.5 micrometres (PM2.5) was evaluated with a pump placed for one week in the classes and in the playground used by the children. Heavy exposure to PM2.5 was associated with a greater amount of exhaled FeNO in both asthmatic and non-asthmatic children. The non-asthmatic children who were heavily exposed in class exhaled 18.3 ppb (95 % CI 14.5-23.2), against 11.3 ppb (95 % CI 10.0-12.2) for those weakly exposed. In this same population, the difference in the FeNO between the non-atopic children weakly exposed and those heavily exposed (8.9 ppb vs. 12.9 ppb) was significantly less than it was between the weakly and the heavily exposed atopic children (11.1 ppb vs. 27.4 ppb). Our study confirms the inflammatory effect of air-borne particles on children with respiratory allergies, not only in asthmatic children but equally in those without pre-existing bronchial inflammation. The results obtained in non-asthmatic atopics confirm the existence of the known adjuvant effect of certain PM2.5 components on the intensity of the allergic inflammatory response.