A comparative study of bone mineral density among patients with obstructive lung diseases in Korea

Decreased bone mineral density (BMD) in patients with obstructive lung disease (OLD) is well known. However, the relationship between BMD and asthma and chronic obstructive pulmonary disease (COPD) overlap syndrome (ACOS) is not yet known.To determine the relationship between ACOS and decreased BMD.We evaluated the relationship between OLD phenotypes and decreased BMD in subjects from the Korean National Health and Nutrition Survey IV and V (2008-2011). Data on 979 subjects who underwent spirometry and dual-energy X-ray absorptiometry were included in the study.Patients with ACOS had lower femur, femur neck and lumbar T-scores than those with COPD (P = 0.048, P = 0.001 and P = 0.002, respectively). On multivariate logistic regression analysis, the ACOS group had a two-fold higher risk of developing osteopenia and low BMD compared to the COPD group (OR 1.960, 95%CI 1.011-3.800, P = 0.046; OR 1.974, 95%CI 1.019-3.824, P = 0.044).The rate of bone loss differed among subjects with the asthma, COPD and ACOS OLD phenotypes. In particular, patients with ACOS had a higher risk of developing osteopenia and low BMD than those with COPD.