Objective To understand the associations between osteoporosis and COPD. Methods The alterations of calcaneal broadband ultrasound attenuation (BUA), sound of speed (SOS) and calcaneal bone mineral content (BMC) and bone mineral density (BMD) and blood partial pressure were measured in thirty old male patients with COPD and in thirty controls. Results The measurement of calcaneal BUA, SOS, and BMD, BMC of the femoral neck, the ward's triangle and the trochanter in the COPD group were significantly lower t...