Relationship between Serum Leptin and Bone Density in Young and Older Women

Abstract

Leptin is involved in the regulation of body weight and energy homeostasis. Recently, it has been linked to bone metabolism with decreased leptin levels being associated with a loss of bone mass. PURPOSE: We examined the relationship between serum leptin levels and bone mineral density (BMD) in sedentary women, ages 18–75 years (n=81). METHODS: Healthy premenopausal (Y; 18–30 yrs; n=32) and postmenopausal (O; 60–75 yrs; n=49) women were recruited for this study. Total body, AP spine, and left proximal femur BMD sites were assessed by DXA (GE Lunar Prodigy, software version 8.80.001). Body composition variables were obtained from the total body scan analysis. Venous blood samples were obtained after an overnight fast, centrifuged and the serum frozen at −84o C until the assays were performed. Serum leptin levels were measured in duplicate using a IRMA kit (Diagnostics Systems Laboratory, Webster TX). RESULTS: Postmenopausal women had significantly lower (p<.01) BMD at the femoral neck, trochanter and total hip sites. Serum leptin levels and percent body fat variables were significantly higher (p<.05) in postmenopausal women than in premenopausal women. There were no significant (p>.05) correlations between serum leptin levels and bone density variables across menopausal status. However, leptin was positively related (p<.05) to regional and total measures of percent body fat (r =.64-.72) and fat mass (r =.60-.73). CONCLUSION: Serum leptin levels were not related to bone mineral density or bone mass in sedentary women. The findings of this study confirmed the positive relationship between leptin levels and body fat.