Differences* in postbronchodilator FEV1 decline for smokers and non-smokers in the non-obstructed, discordant, and obstructed categories
† for the base case population. Bars indicate 95% confidence intervals. FEV1: forced expiratory volume in 1 s; LLN: lower limit of normal. * adjusted for differences in inhaled corticosteroid use between the categories. † based on Swanney  prediction equations for FEV1/FVC.