Lack of osteomalacia in chronic cholestatic liver disease.

Assessment of osteomalacia using rigorous histologic definition was carried out in 36 unselected patients with chronic cholestatic liver disease, 33 with primary biliary cirrhosis, and 3 with primary sclerosing cholangitis. Disease duration varied from 1 to 11 years. The mean values for total trabecular bone volume, osteoid volume, osteoid surface, and mineralization appositional rate were all decreased when compared to age-matched and sex-matched controls. There was a highly significant decrease in the mean osteoid seam width in both females (P = 0.001) and males (P = 0.02), and a significant prolongation of the mineralization lag time was found in females (P = 0.05), but failed to reach significance in males. These results excluded osteomalacia but were more indicative of osteoporosis. Biochemical evidence of osteomalacia was also absent, with serum calcium, serum phosphorus, and mean 25-hydroxyvitamin D levels not significantly different from control values, although there was a nonsignificant decrease in the mean value of 25-hydroxyvitamin D in patients with elevated serum bilirubin levels, and all patients with levels below 20 nmol/L had avoided sunlight exposure. The present results suggest that osteoporosis is the major type of metabolic bone disease in patients with chronic cholestatic liver disease.