Bone density and 25-hydroxyvitamin D level in extrahepatic biliary atresia

Biliary atresia (BA) represents a common cholestatic affliction of the gastrointestinal tract affecting infants and children. The objective of the present study was to evaluate 42 patients (20 with and 22 without jaundice) diagnosed with extrahepatic BA for bone mineral content and serum 25-hydroxyvitamin D (HVD) levels. Physical examination and anthropometric nutritional assessment were performed. The investigation included liver function tests and serum calcium (Ca), phosphate (P), magnesium (Mg), and 25-HVD levels. Dual-energy X-ray absorptiometry was used to measure the bone mineral density (BMD) of the lumbar spine (L(1)-L(4)). Our results showed that 16 jaundiced patients (80%) and only 3 nonjaundiced patients (13.6%) showed osteoporosis (P< 0.05). All patients had normal serum Ca and P levels. Only 1 nonjaundiced patient had a low serum Mg level. Serum 25-HVD levels (mean +/- SD) were 20.71 +/- 8.24, 16.12 +/- 4.3, and 9.18 +/- 5.84 ng/ml, respectively, in subjects with normal bone density (n=7), osteopenia (n=3), and osteoporosis (n=11). Bone disease represents a well-known complication among long-term survivors of BA. To date, the pathogenesis has remained unexplained. Since, as demonstrated in the present study, jaundiced patients develop osteoporosis more frequently than nonjaundiced patients, hyperbilirubinemia may have an influence. Bone-mineral deficiency can be detected earlier by means of BMD measurement (non-invasive method) than by measuring serum Ca, P, and Mg levels in these patients.