Relationship between changes of bone mineral content and twelve-minute walking distance in men with chronic...

Cross-sectional studies have revealed that bone mass is reduced in patients with chronic obstructive pulmonary disease (COPD). To elucidate the factors influencing bone mass in COPD, we measured whole body bone mineral content (BMC) by dual energy X-ray absorptiometry (DXA), pulmonary function, and twelve-minute walking distance (TMD) in men with COPD, who had been monitored for at least one year. We studied the body composition in 22 male patients with COPD and 19 age-matched male controls (age 72.6 +/- 7.2 vs 67.5 +/- 10.1 years, mean +/- SD). COPD patients showed a significantly lower body weight (49.3 +/- 5.7 vs 57.9 +/- 3.5 kg, respectively), body mass index (18.9 +/- 2.1 vs 22.1 +/- 1.3 kg/m2) and BMC (1.9 +/- 0.4 vs 2.2 +/- 0.4 kg) than controls. The changes in BMC were significantly correlated with TMD (r=0.53, p<0.02). These results demonstrate that decreased exercise capacity, at least in part, accounts for acceleration of bone mass loss in COPD patients.