Correlations between leptin, body composition, bone mineral density, and bone metabolism in kidney transplant recipients

INTRODUCTION: In kidney transplant recipients leptin levels are often elevated and bone mineral density (BMD) decreased. However, to date there are no about correlations between leptin and BMD in this population. It has been suggested that leptin is a predictor of BMD in postmenopausal women. Moreover, leptin acts as a marker of fat stores. We examined the relationships between leptinemia, some markers of nutritional status, BMD, and bone metabolism in kidney transplant recipients. We also assessed whether leptin was a significant and independent predictor of BMD in this population. METHODS: BMD and fat content (global, percentage, trunk) were measured using dual-energy X-ray absorptiometry in 27 kidney allograft recipients. Markers of bone turnover and leptin were studied using commercially available kits. RESULTS: Leptin correlated with the percentage of body fat, trunk fat, lean body mass, serum creatinine, and urea. Insulin growth factor binding protein 1 was negatively related to waist-hip ratio and global and trunk fat, whereas BMD of the lumbar spine was correlated with the daily dose of prednisone, azathioprine, cyclosporine trough levels, serum calcium, as well as osteoprotegerin level. CONCLUSIONS: Leptin levels are associated with graft function and body fat in kidney allograft recipients. Leptin is not related to nutritional status, BMD, or bone metabolism in kidney allograft recipients, but is associated with the current dosage of immunosuppressants and the serum calcium.