Inverse relationship between circulating levels of leptin and bone mineral density in chronic liver disease

The pathophysiology of osteoporosis complicating chronic liver disease is unknown. Recent animal studies have found leptin to be a potent inhibitor of bone formation. The aim of this study was to investigate the relationship between serum leptin levels and bone mineral density in patients with chronic liver disease.

Fifty-eight patients, 39 females and 19 males, and age- and gender-matched controls were included. Bone mineral density was measured by using dual energy X-ray absorptiometry. Serum leptin was measured by using a radioimmunoassay.

The mean serum leptin concentration was 10.4 +/- 11.3 and 15.2 +/- 17.9 ng/mL; P=0.11, in the patients and controls, respectively. Leptin correlated positively with body mass index in patients (r=0.40; P=0.003) and in controls (r=0.55; P < 0.0001). In patients classified as Child-Pugh grade B and C, serum leptin correlated negatively with bone mineral density in females at both the lumbar spine and the femoral neck (r=-0.78; P=0.04 and r=-0.86; P=0.03, respectively). In male patients, the correlation was only significant at the lumbar spine (r=-0.99; P=0.002 and r=-0.86; P=0.06, at the lumbar spine and femoral neck, respectively). No correlation was found between serum leptin and bone mineral density in the controls.

An inverse relationship between serum leptin and bone mineral density was found in patients with advanced chronic liver disease. The reasons for these findings are uncertain, but a pathophysiological role of circulating leptin in osteoporosis in chronic liver disease is possible.