To determine whether bone loss in patients with chronic cholestatic liver disease is the consequence of a high or low bone turnover state, 30 female patients with biopy-proven primary biliary cirrhosis underwent iliac ciest biopsy following double tetracycline labeling. The meam trrrbecalar bone volume was decreased as a result of trukcular plate thinning in both the premenopausal (p < 0.02) and poetmenopausal (p < 0.05) patients, compared to ageand sex-matched controls. Indications that oeteoblaetic function was impaired included a signifb m t l y lower mean wall thickness (p c 0.01) and mean -i d seain width (p c 0.05). and this in association with a decreased mineral appositional rate and prolonged mineralization lag time was suggestive of a defect in matrix synthesis. Further evidence of impaired mteoblnatic activity was the significantly lower bone formation rate at both tissue (p < 0.001) and basic multicellular unit levels (p < 0.05) in the postmenopausal patients. Total resorption surfaces and fasting urinary calcium/creatinine ratios were significantly increased (p < 0.005 and 0.05, respectively) in the premenopausal patients and mean interstitial bone thickness reduced in both pre-and postmenopausal patients, suggesting that increaeed m r p t i o n may also contribute to bone loss in primary biliary cirrhosis.
In symptomatic primary biliary cirrhosis (PBC) with jaundice and steatorrhea consequent upon bile salt deficiency, malabsorption of fat-soluble vitamins, including vitamin D is likely, and sequestration of calcium by undigested fats also occurs in these patients. Because of these features, osteomalacia might be expected to occur commonly, as was reported in some early studies (1-5). More recent work, however, has suggested that osteoporosis is the metabolic bone disease most frequently found in this disorder ( 6 4 although in one recently reported study (9), another type of bone lesion was described in which bone histomorphometry showed increased bone resorption and turnover in the absence of osteoporosis and osteomalacia. In a detailed study of bone histomorphometry in PBC, we have found little evidence for osteomalacia (10). Both cortical and trabecular osteoporosis were frequently detected ( l l ) , and in the present