Normal bone mineral density in cystic fibrosis

Background-Osteoporosis has been reported as a complication of cystic fibro sis (CF). Aims-To measure bone mineral density (BMD) in non-acutely ill adults and bo ne mineral content (BMC) in children with CF. Methods -We analysed data from 28 adults and 13 children with CF. Corticost eroid use was minimal for the year prior to study in both groups. Dual x ra y absorptiometry was used to measure total body and regional bone mineral d ensity in adults. In children, whole body BMC was measured. Lean tissue mas s (LTM) was also measured in all subjects. There were two control groups: A (matched for LTM and height, in addition to age and gender); and B (matche d for age and gender only). Results-There was no difference in whole body or regional BMD density betwe en adult CF patients and control A subjects. Both whole body and regional B MD were significantly lower in adult CF patients than in control B subjects . Total body BMD was correlated with body mass index, LTM, and percent fat in both CF and control subjects. There was no significant correlation betwe en total body BMD or regional BMD and either NIH clinical status scores, or pulmonary function tests in adults. There was no difference in total body BMC between CF children and control A subjects. Total body BMC was signific antly lower in CF children than in control B subjects. There was no correla tion between pulmonary function results and BMC in children. Conclusion-Osteopenia and osteoporosis in CF may be caused more by malnutri tion and chronic use of intravenous or oral corticosteroids than by a CF re lated inherent defect in BMD. Appropriate "normal" data should be selected when determining whether or not osteoporosis is present in a CF patient.