In children with end-stage liver disease, little is known regarding the long-term effects of liver transplantation on bone. In this 2-year prospective study, we evaluated the effects of liver transplantation on bone mineral density (BMD) and on other parameters of bone metabolism in 30 consecutive children with biliary atresia who underwent liver transplantation after failed Kasai operation. Tacrolimus and steroids were used as immunosuppressants. BMD of the first through fourth lumbar spine (L1-4) was measured by dual-energy radiographic absorptiometry (QDR-2000, Hologic) and expressed in Z-values. Before transplantation, Z-values of BMD, height, and weight were low in all patients (-3.4 +/- 0.34, -2.0 +/- 0.28, and -1.67 +/- O.16 [mean +/- SEM], respectively). Low BMD states were associated with low levels of serum 25-hydroxyvitamin D and serum levels of insulin-like growth factor-I (IGF-I), one of the most potent anabolic skeletal growth factors. Liver transplantation resulted in marked improvement in BMD values as well as in height and body weight: 24 months after transplantation, recovery was achieved in each parameter (0.16 +/- 0.30, -0.29 +/- 0.23, and 0.42 +/- 0.18, respectively). BMD recovery first was observed 3 months after transplantation. Moreover, these favorable effects of transplantation were accompanied by increases in serum levels of 25-hydroxyvitamin D and IGF-I. We conclude that liver transplantation effectively reverses the low bone mass status and growth retardation of children with end-stage liver disease.