Abstract
It is not clear yet whether airway hyperresponsiveness (AHR) and lung function decline can be associated with bone mineral density. We therefore retrospectively analyzed 34 asthmatic females (mean age 48.4±9.6;mean baseline FEV1%:99.4±13.1) that had performed a methacholine challenge test (10 hyperreactive subjects; median PD20:358µg, IQR:240-806) and bone density scan (mean femoral-t-score:-0.7±0.9; mean vertebral t-score:-1.3±1.4) at asthma onset. Furthermore, to investigate a link between FEV1 decline and bone density changes in time, we considered the 23 asthmatics that had repeated such exam and FEV1 measurements at least 5 years later. No significant relationships were found either between baseline femoral/vertebral-t-scores (r=0.13; r=0.03; p=n.s), and PD20 or FEV1 decline (r=-0.09; r=-0.16; p=n.s). After 7.6±1.7 years, we found a FEV1 decline of 52.9±42.7 ml/year and a mean difference of femoral-t-score 0.09 and vertebral-t-score 0.26 in the 23 asthmatics. When comparing both FEV1 decline and t-score changes in hyperreactive/normoreactive subjects, no differences were found. On the contrary, we detected a significantly positive relationship between changes of femoral-t-scores and FEV1 decline (r=0.43;p=0.04). This suggests an association between bone density impoverishment and lung function deterioration, probably due to the inhaled corticosteroids influence on bone mineral density. However, since the vitamin D level is associated both with asthma severity and osteopenia/osteoporosis, low levels of this vitamin may negatively influence both bone density loss and FEV1 decline. Therefore, when managing asthmatics with an accelerated FEV1 decline, a bone density scan and vitamin D integration should be considered.
- © 2014 ERS