Pathogenesis of osteoporosis in liver cirrhosis

Osteoporosis has been recognized in patients with liver cirrhosis, although the prevalence and the exact mechanisms vary considerably in the literature. We have studied the prevalence of bone disease in cirrhotic patients, the pathogenesis and the relation to the etiology and the severity of liver failure.

The study included 83 hospitalized patients with various types of cirrhosis, where 25 healthy individuals served as controls. Patients were classified according to Child-Pugh's stages as follows: Child A: 49, Child B: 20, Child C: 14. Serum levels of iPTH, 250HD, LH, FSH, SHBG, testosterone, estradiol, IGF-I, osteocalcin and urine levels of cross-linked N-telopeptides of collagen type 1 (NTX) were measured in all patients. Bone mineral density (BMD) was measured by DEXA at the spine of both patients and controls.

The prevalence of osteoporosis was higher in patients (26/83) 31.3% than in controls (4/25) 16%. Osteopenia was positively related with the elevated levels of crosslinked N-telopeptides (p=0.048). There were no differences in BMD between the types of cirrhosis. BMD was found to be significantly lower in Child B and C male patients than in Child A (p=0.043). Patients' groups B, and C had lower testosterone levels with a trend to contribute to the low BMD (p=0.15). 250HD and IGF-1 were significantly lower in decompensated cirrhosis (p<0.002), but did not correlate with BMD.

Cirrhosis is a major cause of osteoporosis and the degree of osteopenia is related to the severity and not the etiology of the liver disease. The biochemical markers of bone remodeling suggest a high-turnover osteoporosis in cirrhosis.