Osteoporosis in chronic liver disease.

Osteoporosis is a frequent complication in patients with chronic liver disease, especially in end-stages and in chronic cholestasis, in addition to non-alcoholic fatty liver disease, haemochromatosis and alcoholism. Mechanisms underlying osteoporosis are poorly understood, but osteoporosis mainly results from low bone formation. In this setting, sclerostin, a key regulator of the Wnt/β-catenin signalling pathway which regulates bone formation, in addition to the effects of the retained substances of cholestasis such as bilirubin and bile acids on osteoblastic cells, may influence the decreased bone formation in chronic cholestasis. Similarly, the damaging effects of iron and alcohol on osteoblastic cells may partially explain bone disease in haemochromatosis and alcoholism. A role for proinflammatory cytokines has been proposed in different conditions. Increased bone resorption may occur in cholestatic women with advanced disease. Low vitamin D, poor nutrition and hypogonadism, may be contributing factors to the full picture of bone disorders in chronic liver disease.