Bone Abstracts

Objectives: Bone disease is now well described in cystic fibrosis adult patients. CF bone disease is multifactorial but many studies suggested the crucial role of inflammation and chronic pulmonary infection. The objectives of this study were to assess the prevalence of osteoporosis in a current adult CF population and to examine its relationship with infections and inflammation.

Methods: Patients were recruited in the adult CF Lyon Centre and assessed in clinically stable period, later during a respiratory infection, and finally 14 days after the end of antibiotic therapy. At each time points, we performed a clinical evaluation, lung function tests and biochemical tests: markers of inflammation (CRP, IL6, and TNFα), serum markers of bone turnover (serum CTX), and serum RANK-L and OPG. Absorptiometry and dorso-lumbar radiographs were also performed. We enrolled 56 patients (29 men, mean age of 26). Bone mineral density (BMD) values indicated osteopenia in 41% and osteoporosis in 14% of patients. We found one or two vertebral fractures on radiographs in two patients without any history of previous fracture. After infections treated with antibiotics, serum RANK-L and OPG were increased (+24%, P=0.08 and +13%, P=0.04 respectively), with a stable ratio. This increase was delayed in comparison to the increase of inflammation markers. Serum CTX were stable during pulmonary infections. No significant correlation was found between serum inflammation markers, CTX and RANK-L.

Conclusion: In this study, bone disease among adult CF patients was less severe than previously described. We found a mild increase of serum RANK-L levels, delayed compared with the pulmonary infections, and independent from the bone resorption level.