Osteoporosis is highly prevalent in Japanese males with chronic obstructive pulmonary disease and is associated with deteriorated pulmonary function

Osteoporosis has recently been recognized as a major comorbidity in chronic obstructive pulmonary disease (COPD). We conducted a cross-sectional study in a cohort of 136 Japanese males with COPD to evaluate the prevalence of vertebral fracture (VF) and to explore its relationship with pulmonary function parameters. VFs were present in 108 (79.4 %); multiple and severe (SQ grade 2 or 3) VFs were found in 77 (56.6 %) and 25 (18.4 %), respectively. Multivariate logistic regression analyses revealed that decrease in forced expiratory volume in one second (FEV1.0)/forced vital capacity (FVC) [odds ratio (OR) 0.963, 95 % confidence interval (CI) 0.929-998, p = 0.036] was associated with the presence of VF after adjustment for age and that FVC (OR 0.462, 95 % CI 0.220-0.968, p = 0.041) and current smoking (OR 2.992, 95 % CI 1.128-7.940, p = 0.028) were associated with VF severity (grade 2-3 vs. 1). We also found that FEV1.0 was the sole independent determinant of the number of VFs by stepwise multivariate linear regression (p < 0.001). Bone mineral density (BMD) values were available in 49 subjects. Mean T scores were -2.0 +/- 1.2 in femoral neck, -1.4 +/- 1.2 in total hip and -1.1 +/- 1.4 in lumbar spine. Nineteen patients (38.8 %) had a BMD T score less than -2.5. BMD Z scores of all the sites showed a progressive decrease as GOLD stage of COPD advanced (p < 0.05). Our results indicate a high prevalence of osteoporosis in Japanese male COPD patients and a strong inter-relationship between the two diseases, re-emphasizing the urgent need for appropriate intervention to maintain both bone and lung health.