Bone density in children and adolescents with cystic fibrosis

Abstract

OBJECTIVE: To assess bone mineralization in children and adolescents with cystic fibrosis. DESIGN: A cross-sectional, observational study of bone mineral density (BMD) in the lumbar vertebrae and the proximal femur of 62 patients aged 4.9 to 17.8 years (mean, 10.7 years). The age-normalized BMD findings ( z scores) were correlated with multiple variables, including measures of pulmonary disease, nutritional status and growth, genotype, calcium intake, and serum 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D levels. RESULTS: The mean BMD zscore was –1.03 ± 0.14 (±SE) in the lumbar vertebrae and –0.71 ± 0.17 in the proximal femur. The BMD in this age range declined relative to normal values at a rapid rate of roughly 1 SD every 6 to 8 years. The BMD z scores correlated well with multiple measures of disease severity, particularly weight and forced expiratory volume in 1 second. CONCLUSIONS: Significant osteoporosis in adults with CF results at least in part from a failure to accumulate bone mineral at a normal rate during skeletal growth and development. The cause of this is likely multifactorial. With increasing longevity, the skeletal consequences of CF become an important consideration. (J P EDIATR 1996;128:28-34)