RT Journal Article SR Electronic T1 PM10 is associated with an increase in day-by day inspiratory resistance variability in asthma JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society SP P4784 VO 40 IS Suppl 56 A1 Alessandro Gobbi A1 Paola Gasparini A1 Carlo Gulotta A1 Vito Brusasco A1 Antonio Pedotti A1 Riccardo Pellegrino A1 Raffaele DellacĂ  YR 2012 UL http://erj.ersjournals.com/content/40/Suppl_56/P4784.abstract AB Background: An increased variability of inspiratory resistance, measured by forced oscillations (FOT) and quantified by the coefficient of variation measured over 4 consecutive days (CVRinsp), is a typical feature of asthma and predicts acute deterioration of airway function within a week.Aim: To investigate whether air pollution increases CVRinsp and the risk of future deterioration in asthma.Methods: Between Jan and Jul 2009, CVRinsp was measured daily by a portable FOT device in 10 mild asthmatics. CVRinsp was then compared with the daily concentration of PM10.Results: In 7 subjects PM10 was linearly correlated with CVRinsp (r=0.27, p<0.05). In these individuals CVRinsp time-series were then averaged to reduce intra-individual variability (Figure) and used to estimate a linear ARMAX model, with the PM10 as input and a white noise modelling unknown effects on the variability. According to the Akaike criterion, the CVRinsp at a given day was best modelled by a weighted average of the PM10 over the past 4 days.Conclusions: The concentration of PM10 is associated with an increase in airway resistance variability in asthma, leading to a greater likelihood of future functional deterioration.