title: Differences in regional air trapping in current smokers with normal spirometry.
abstract: We investigated regional air trapping on computed tomography in current smokers with normal spirometry. It was hypothesised that presence of regional air trapping may indicate a specific manifestation of smoking-related changes.40 current smokers, 40 patients with chronic obstructive pulmonary disease (COPD), and 40 healthy never- smokers underwent computed tomography scans. Regional air trapping was assessed on end-expiratory scans and emphysema, micronodules and bronchial wall thickening on inspiratory scans. The ratio of expiratory and inspiratory mean lung attenuation (E/I) was calculated as a measure of static (fixed) air trapping.Regional air trapping was present in 63% of current smokers, in 45% of never smokers and in 8% of COPD patients (p<0.001). Current smokers with and without regional air trapping had E/I ratio of 0.81 and 0.91, respectively (p<0.001). Forced expiratory volume in 1 s (FEV1) was significantly higher and emphysema less frequent in current smokers with regional air trapping.Current smokers with regional air trapping had higher FEV1and less emphysema on computed tomography. In contrast, current smokers without regional air trapping resembled COPD. Our results highlight heterogeneity among smokers with normal spirometry and may contribute to early detection of smoking related structural changes in the lungs.
authors.affiliation: Dept of Medicine and Centre for Molecular Medicine (CMM) Respiratory Medicine Unit, Karolinska Institutet, Karolinska University Hospital Solna, Stockholm, Sweden reza.karimi@ki.se.|These authors contributed equally.
authors.forename: Reza
authors.initials: R
authors.lastname: Karimi
authors.affiliation: Dept of Medicine and Centre for Molecular Medicine (CMM) Respiratory Medicine Unit, Karolinska Institutet, Karolinska University Hospital Solna, Stockholm, Sweden.
authors.forename: Göran
authors.identifier: 0000-0002-8718-6631
authors.initials: G
authors.lastname: Tornling
authors.affiliation: Dept of Medicine and Centre for Molecular Medicine (CMM) Respiratory Medicine Unit, Karolinska Institutet, Karolinska University Hospital Solna, Stockholm, Sweden.
authors.forename: Helena
authors.initials: H
authors.lastname: Forsslund
authors.affiliation: Dept of Medicine and Centre for Molecular Medicine (CMM) Respiratory Medicine Unit, Karolinska Institutet, Karolinska University Hospital Solna, Stockholm, Sweden.
authors.forename: Mikael
authors.initials: M
authors.lastname: Mikko
authors.affiliation: Dept of Medicine and Centre for Molecular Medicine (CMM) Respiratory Medicine Unit, Karolinska Institutet, Karolinska University Hospital Solna, Stockholm, Sweden.
authors.forename: Åsa M
authors.initials: ÅM
authors.lastname: Wheelock
authors.affiliation: Dept of Molecular Medicine and Surgery, Division of Radiology, Karolinska Institutet, Karolinska University Hospital Solna, Stockholm, Sweden.|These authors contributed equally.
authors.forename: Sven
authors.initials: S
authors.lastname: Nyrén
authors.affiliation: Dept of Medicine and Centre for Molecular Medicine (CMM) Respiratory Medicine Unit, Karolinska Institutet, Karolinska University Hospital Solna, Stockholm, Sweden.|These authors contributed equally.
authors.forename: C Magnus
authors.initials: CM
authors.lastname: Sköld
mesh_terms: D000368:Aged; D000388:Air; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology; D001999:Bronchoscopy; D016022:Case-Control Studies; D005260:Female; D005541:Forced Expiratory Volume; D005652:Functional Residual Capacity; D006801:Humans; D016014:Linear Models; D008168:Lung / Q000000981:diagnostic imaging* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D015588:Observer Variation; D029424:Pulmonary Disease, Chronic Obstructive / Q000000981:diagnostic imaging* / Q000503:physiopathology; D011656:Pulmonary Emphysema / Q000000981:diagnostic imaging*; D012907:Smoking / Q000503:physiopathology*; D013147:Spirometry; D013548:Sweden; D014057:Tomography, X-Ray Computed