Restrictive pulmonary dysfunction is associated with vertebral fractures and bone loss in elderly postmenopausal women

Association between lung function and bone metabolism remains controversial. We found that impaired lung function was associated with vertebral fractures and bone loss in Japanese postmenopausal women. While vertebral deformities would impair lung function, respiratory dysfunction might in turn increase fracture risk, suggesting a complex bidirectional interaction. Introduction Association between bone metabolism and pulmonary function in the general population is controversial. The aim of this study was to investigate relationship between lung and bone parameters in elderly postmenopausal women. Methods One hundred and six postmenopausal women (75.6 +/- 8.0 years old) who underwent spirometric tests were examined for prevalent vertebral fractures, bone mineral density (BMD), bone metabolic markers, and other metabolic indices such as urinary pentosidine. Results Multivariable logistic regression analyses revealed that forced vital capacity (FVC) (OR = 0.063, 95% CI: 0.011-0.352, p = 0.002) and urinary pentosidine (OR = 1.067, 95% CI: 1.020-1.117, p = 0.005) were associated with the presence of vertebral fractures after adjustment for height loss, age, and BMD at femoral neck. Moreover, vital capacity (VC) or FVC as well as body mass index and age was among independent determinants of BMD after adjustment for height loss and the number and grade of vertebral fractures in forced multiple linear regression analysis (VC: beta = 0.212, p = 0.021, FVC: beta = 0.217, p = 0.031). Urinary pentosidine was negatively correlated with pulmonary function parameters such as FVC and forced expiratory volume in 1 s (FEV1.0), although these correlations appeared dependent on age. Conclusions Diminished FVC was associated with prevalent vertebral fractures and decreased BMD in Japanese postmenopausal women without apparent pulmonary diseases. Mechanism of such association between pulmonary function and bone status remains to be determined.