Degree of structural CT changes (emphysema. airway wall thickening and gas trapping) for the total population and stratified by classification of airflow limitation.

Univariate analysis with the group FEV1/FVC >70% as reference. # p<0.001. Log950% =  log-transformed percentage of voxels below HU -950. E/I-ratio%  =  expiratory mean lung density in HU divided by the inspiratory mean lung density in HU expressed as a percentage. Pi10 =  the square root of wall area for a theoretical airway with 10mm lumen perimeter.