Inflammatory related changes in bone mineral content in adults with cystic fibrosis
- 1Department of Medicine, University of Manchester, Manchester Royal Infirmary, Manchester M13 9WL, UK
- 2Adult Cystic Fibrosis Centre, South ManchesterUniversity Hospitals NHS Trust, Wythenshawe Hospital, ManchesterM23 9LT, UK
- 3Belfast Adult Cystic Fibrosis Centre, Belfast City Hospital, Belfast, UK
- 4MRC Biostatistics Unit and Research and Development Unit, Papworth Hospital, Cambridge CB3 8RE, UK
- 5Clinical Radiology, Imaging Science and Biomedical Engineering, University of Manchester, Manchester M13 9PT, UK
- Correspondence to:
Dr C S Haworth
Adult Cystic Fibrosis Centre, Papworth Hospital, Papworth Everard, Cambridge, CB3 8RE, UK;
- Received 26 June 2003
- Accepted 16 March 2004
Background: Proinflammatory cytokines stimulate osteoclast activity and this could lead to increased bone resorption in patients with cystic fibrosis. The aim of this study was to determine whether markers of systemic inflammation are related to changes in bone mineral content (BMC) in adults with cystic fibrosis.
Methods: Total body BMC was assessed by dual energy x ray absorptiometry in 100 patients (54 male) of mean (SD) age 25.6 (7.1) years and forced expiratory volume in 1 second (FEV1) 61.8 (24.1)% predicted on recruitment to the study and 1 year later. Blood was also taken at these time points to measure markers of systemic inflammation.
Results: After 1 year BMC had reduced by 16.1 (62.1) g, p = 0.01; (0.6 (2.8)%). The change in BMC was related to mean levels of interleukin (IL)-6 (rs = −0.39, p<0.001) and C reactive protein (rs = −0.34, p = 0.002), intravenous antibiotic use (rs = −0.27, p = 0.006) and oral corticosteroid use (rs = −0.20, p = 0.045). Urinary markers of osteoclast activity were also related to IL-6 (rs = 0.27, p = 0.02). Multiple linear regression revealed that IL-6 (coefficient –2.2 (95% CI –3.4 to –1.0) per pg/ml, p = 0.001), colonisation with Burkholderia cepacia (coefficient –46.8 (95% CI –75.5 to –18.1), p = 0.002), and annual change in BMI (coefficient 15.4 (95% CI 3.6 to 27.2) per kg/m2, p = 0.011) were independently significant predictors of annual change in BMC.
Conclusions: These data suggest a pathophysiological mechanism by which chronic pulmonary infection results in bone loss in patients with cystic fibrosis.
- BMC, bone mineral content
- BMD, bone mineral density
- BMI, body mass index
- BSAP, bone specific alkaline phosphatase
- CRP, Creactive protein
- FEV1, forced expiratory volume in 1 second
- IL-6, interleukin 6
This study was funded by the Cystic Fibrosis Trust.