Metabolic bone disease is common in patients with cholestatic liver disease. The importance of vitamin D status and calcium malabsorption in the pathogenesis of bone disease in these patients remains undefined. We have measured intestinal calcium absorption in relation to vitamin D status in 14 patients with chronic cholestatic liver disease including 11 with primary biliary cirrhosis. Fractional calcium absorption was determined from radioactive counts in the right forearm after separate oral and intravenous doses of 47CaC12 in the fasting state. Eight of 14 patients (57%) had a decreased calcium absorption compared to controls. A significant correlation was observed between serum 25-hydroxyvitamin D levels and fractional calcium absorption (r = 0.623, p < 0.02). Treatment with oral 25-hydroxyvitamin D3 in three patients with low serum 25-hydroxyvitamin D levels resulted in correction of serum 25-hydroxyvitamin D levels and improvement in fractional calcium absorption. No correlation was found between serum 1725-dihydroxyvitamin D levels and fractional calcium absorption (r = 0.22 1). Calcium malabsorption was common in this series of patients, and serum 25-hydroxyvitamin D levels were useful in predicting fractional calcium absorption. Treatment with oral 25-hydroxyvitamin Ds was accompanied by improved calcium absorption.
Bone disease is a cause of significant morbidity in patients with primary biliary cirrhosis and other chronic cholestatic liver diseases (1, 2). Osteoporosis appears to be the most common form of bone pathology (3-5); osteomalacia also occurs in some patients (6-8). Vitamin D deficiency is well documented in many patients with primary biliary cirrhosis (5,6,(8)(9)(10)(11), although in others normal serum levels of 25-hydroxyvitamin D [25(OH)D] and 1,25-hydroxyvitamin D [ 1,25(OH)2D] are reported (4, 12). Intestinal calcium malabsorption has been demonstrated in some patients with primary biliary cirrhosis but the relationship between vitamin D status and intestinal calcium malabsorption in these patients remains uncertain (4, 5,9).
Our objective was to study intestinal calcium absorption and its relation to vitamin D status in a group of patients with primary biliary cirrhosis and other chronic