Cystic fibrosis-related bone disease explored using a four step algorithm.

ABSTRACT

BACKGROUND: A suboptimal bone accrual in young individuals with cystic fibrosis (CF) may be related to the development of a premature CF-related bone disease. Dual energy X-ray absorptiometry (DXA) is the mainstream measure of bone health; however, the influence of body size and lean tissue mass (LTM) on bone data is poorly interpreted. METHODS: Total body dual-energy X-ray absorptiometry (DXA) measurements of bone mineral content (BMC) and LTM in 53 individuals with CF (7.00-17.99years) were compared to 53 sex-matched controls. BMC, height, and LTM in relation to height and BMC Z-scores were calculated and used in a 4-step algorithm. RESULTS: Pubertal females with CF had less total body BMC for age (p=0.02); pre-pubertal males (p=0.05) and pubertal females with CF (p=0.03) were shorter; and pubertal females with CF showed less total body BMC for LTM (p=0.01). CONCLUSIONS: The algorithm showed the following (1) prior to puberty lowered total body BMC was primarily due to short stature, (2) LTM was appropriate for body size, and (3) pubertal females with CF had significantly less total body BMC for their LTM. Longer controlled trials are needed to clinically interpret CF-related bone disease using DXA derived data that considers patient size and body composition.