A cross-sectional study of bone mineral density in children and adolescents attending a Cystic Fibrosis Centre.

BACKGROUND

Low bone mineral density is common in adults with cystic fibrosis. Children with good lung function compared to controls matched for body size have normal bone mineralisation. There are few data in large unselected populations of children.

METHODS

All children between five and 16 years were invited to take part. Disease severity was assessed. Bone mineral measurements using a GE-Lunar Prodigy densitometer were expressed as age and gender matched Z-scores. Bone mineral apparent density for L2-L4 was estimated and data from UK Caucasian children used to create age and gender specific reference ranges for predicted values. Z-scores were calculated. Total body analysis utilised the Molgaard method. Blood was sampled for measurement of 25-hydroxyvitamin D, and parathyroid hormone levels.

RESULTS

107 children entered the study. 18 and 10 children had low areal and apparent bone mineral density respectively. Short, narrow bones were common. Fifteen children reported 22 fractures, 20 with associated trauma. The best predictors of bone status were ZBMI and percent predicted FEV(1).

CONCLUSIONS

Bone mineral density corrected for body size was normal in over 90% of children. These results are similar to previously reported results in small studies of children with well preserved respiratory function.