1010 Bone mineral density (BMD) in cystic fibrosis (CF)

Improvements in management of CF over the past 2-3 decades have impacted positively on health status, quality of life and life expectancy. However, since there is currently no cure for the condition, the onus remains on health practitioners to monitor and manage patients, particularly during transitional periods such as childhood to adolescence, and adolescence to adulthood which, if nothing else, may involve transitioning from one set of health care providers to another. Bone health has been identified as an area for monitoring: osteopaenia is not uncommon in adult CF patients and may be associated with fragility fractures and spinal deformity, the latter potentially affecting lung mechanics and respiratory status. Possible reasons for reduction in BMD include poor nutrition, small bone size, pancreatic insufficiency, calcium and vitamin D malabsorption, reduced physical activity, steroid treatment, delayed puberty, chronic lung infection, and elevated levels of osteoclast activating cytokines. Overall the picture is one of failure to accrete bone rather than bone loss. While some more-recent studies have reported on normal BMD in well-nourished CF patients, reports are still mixed. In this regard, an Italian study involving 82 CF patients and a similar number of matched controls has shown that 54.8% had reduced bone density (40.2% mild reduction and 14.6% severe, with mild being lumbar spine Z-score -1.0 to -2.0, and severe being lower than -2.0). One-third of the patients were between 5 and onset of puberty, slightly over half were between puberty and 18, and about 12% were young adults. All were on high caloric diets, took multivitamin preparations (without calcium), and all were receiving inhaled steroids. BMD was inversely related to the Shwachman-Kulczycki disease-severity score, the Crispin-Norman radiological score, and to FEV1. There were also positive correlations with BMI, lean mass and total fat mass. The authors conclude that significant BMD abnormalities may be found in CF patients, even in pre-adolescents, and that this may mostly relate to nutrition. Careful monitoring and follow-up are required to avoid later bone disease and fractures.

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BMC Pediatrics 2009,9:61 doi:10.1186/1471-2431-9-61
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