International Journal of COPD (Jun 2016)
Smokers with emphysema and small airway disease on computed tomography have lower bone density
Abstract
Esther Pompe,1 Pim A de Jong,2 Eva M van Rikxoort,3 Leticia Gallardo Estrella,3 Werner U de Jong,2 Rozemarijn Vliegenthart,4,5 Matthijs Oudkerk,5 Carlijn M van der Aalst,6 Bram van Ginneken,3 Jan-Willem J Lammers,1 Firdaus AA Mohamed Hoesein2 1Department of Pulmonology, 2Department of Radiology, University Medical Center Utrecht, Utrecht, 3Department of Radiology, Radboud University Medical Center, Nijmegen, 4Center for Medical Imaging-North East Netherlands, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands; 5Department of Radiology, University of Groningen, University Medical Center Groningen, Groningen, 6Department of Public Health, Erasmus Medical Center, Rotterdam, the Netherlands Abstract: Osteoporosis is more common in patients with COPD and in smokers. The aim of this study was to assess whether measures of emphysema and airway disease on computed tomography (CT) were associated with lower bone density or vertebral fractures in smokers with and without COPD. For this purpose, we included participants from the NELSON lung cancer screening trial. Bone density was measured as Hounsfield Units in the first lumbar vertebra, and vertebral fractures were assessed semiquantitatively. The 15th percentile method (Perc15) was used to assess emphysema, and the airway lumen perimeter (Pi10) was used for airway wall thickness. Expiratory/inspiratory-ratiomean lung density (E/I-ratioMLD) was used as a measure for air trapping and tracheal index to assess tracheal deformity. Linear regression models and logistic regression models were used to assess associations between CT biomarkers, bone density, and presence of fractures. Exactly 1,093 male participants were eligible for analysis. Lower Perc15 and higher E/I-ratioMLD were significantly associated with lower bone density (b=-1.27, P=0.02 and b=-0.37, P=0.02, respectively). Pi10 and tracheal index were not associated with bone density changes. CT-derived biomarkers were not associated with fracture prevalence. Bone density is lower with increasing extent of emphysema and small airway disease but is not associated with large airway disease and tracheal deformity. This may indicate the necessity to measure bone density early in smokers with emphysema and air trapping to prevent vertebral fractures. Keywords: phenotyping, computed tomography, air trapping, emphysema, COPD, bone density
