Abstract
Chronic obstructive pulmonary disease (COPD) is associated with osteoporosis and fragility fractures. The objectives of this study were to assess static and dynamic indices of cancellous and cortical bone structure in postmenopausal women with COPD. Twenty women with COPD who had not received chronic oral glucocorticoids underwent bone biopsies after double tetracycline labeling. Biopsies were analyzed by histomorphometry and Β΅CT and compared with ageβmatched controls. Distribution of the patients according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) was: Type I (15%), Type II (40%), Type III (30%), and Type IV (15%). Mean (Β±SD) cancellous bone volume (15.20βΒ±β5.91 versus 21.34βΒ±β5.53%, pβ=β.01), trabecular number (1.31 βΒ±β 0.26 versus 1.77βΒ±β0.51/mm, pβ=β.003), and trabecular thickness (141βΒ±β23 versus 174βΒ±β36 Β΅m, pβ=β.006) were lower in patients than in controls. Connectivity density was lower in COPD (5.56βΒ±β2.78 versus 7.94βΒ±β3.08/mm, pβ=β.04), and correlated negatively with smoking (rβ=ββ0.67; pβ=β.0005). Trabecular separation (785βΒ±β183 versus 614βΒ±β136 Β΅m, pβ=β.01) and cortical porosity (4.11βΒ±β1.02 versus 2.32βΒ±β0.94 voids/mm^2^; pβ<β.0001) were higher in COPD while cortical width (458βΒ±β214 versus 762βΒ±β240 Β΅m; p<β.0001) was lower. Dynamic parameters showed significantly lower mineral apposition rate in COPD (0.56βΒ±β0.16 versus 0.66βΒ±β0.12 Β΅m/day; pβ=β.01). Patients with more severe disease, GOLD III and IV, presented lower bone formation rate than GOLD I and II (0.028βΒ±β0.009 versus 0.016β+β0.011 Β΅m^3^/Β΅m^2^/day; pβ=β04). This is the first evaluation of bone microstructure and remodeling in COPD. The skeletal abnormalities seen in cancellous and cortical bone provide an explanation for the high prevalence of vertebral fractures in this disease. Β© 2010 American Society for Bone and Mineral Research