Is significant cystic fibrosis-related liver disease a risk factor in the development of bone mineralization abnormalities?

In order to assess the effects of significant cystic fibrosis-related liver disease (CFLD) on bone health, we compared the bone mineral status of older children and adolescents with CFLD to those with cystic fibrosis (CF) alone. Thirteen children (age range, 10-19 years) from our clinical CF services were identified with significant CFLD (9 of these 13 patients had clinical and radiological evidence of portal hypertension). This cohort was then matched by age, gender, and anthropometric measurements with equal numbers of patients with CF alone. All patients had a dual-energy X-ray absorptiometry (DEXA) scan to determine bone mineral content (BMC), bone area (BA), bone mineral density (BMD), and bone mineral apparent density (BMAD) in the region of the lumbar spine. Blood was drawn to determine serum vitamin A, D, E, and K status and liver function tests. The best forced expired volume in 1 sec (FEV1) for each patient in the 12 months around the time of the scan was also documented. Patients with CFLD had slightly worse FEV1 (82 +/- 20% vs. 91 +/- 16%, P = 0.05) and significantly higher alanine aminotransferase (65.5 +/- 35 IU/l vs. 30 +/- 20 IU/l, P = 0.01) than those with CF alone. The mean lumbar spine BA, BMC, BMD, and BMAD were not different between children with CFLD and CF. In conclusion, the presence of significant liver disease in children with CF does not appear to be an additional risk factor for the development of abnormal bone mineralization.