Background and goals: Alterations in bone metabolism in primary biliary cirrhosis (PBC) are generally considered to be highly prevalent and severe, but no data are available from prospective studies with adequate control groups. The aims of this study were: (1) to measure changes in bone mineral density (BMD) over time; (2) to correlate the degree of bone loss with the severity of liver disease; and (3) to characterize bone disease in PBC patients receiving regular calcium and vitamin D supplementation.
Study: We enrolled 118 women with PBC (mean age+/-SD: 56+/-11 y; 72% postmenopausal; 43% with cirrhosis), and measured BMD (lumbar spine, DXA-Hologic) at entry and serially over the following 5 years. The controls were 472 healthy women selected from a large observational group matched for age and menopausal status (mean age+/-SD: 55+/-10 y; 73% postmenopausal).
Results: Mean BMD was 0.851+/-0.142 g/cm2 in the PBC group and 0.857+/-0.158 g/cm2 in the control group; the prevalence of osteoporosis was 28% and 29%, respectively. BMD significantly correlated with age and postmenopausal status, but not with liver cirrhosis or serum bilirubin levels. The biochemical markers of bone turnover were high in about 50% of the patients. The yearly bone loss in the PBC group was 0.008 g/cm2 (95% confidence interval: 0.014-0.003) similar to that calculated in the control group.
Conclusions: Among patients with PBC, the prevalence of osteoporosis and the yearly rate of BMD loss are similar to those observed in the general population, and are not associated with the severity of liver disease.