Association between circulating levels of adiponectin and indices of bone mass and bone metabolism in middle-aged post-menopausal women

Background: Adiponectin, a fat derived cytokine, is a potential independent contributor to bone mineral density (BMD); however, its action on bone metabolism in humans is still unclear. Aim: The aim of this study was to investigate the relationship of adiponectin with bone mass indices and bone metabolic markers in middle-aged post-menopausal women without diabetes. Subjects and methods: A random sample consisted of 81 post-menopausal women (age range 45-61 yr, osteopenic/osteoporotic no.=43) was studied. Lumbar-spine BMD (BMDL2-L4) and total-body bone mineral content (TBBMC) were measured with dual X-ray ab-sorptiometry. Plasma levels of total and high-molecular weight (HMW) adiponectin, osteoprotegerin (OPG), soluble receptor activator of nuclear factor-kappa B ligand (sRANKL) and IGF-I were determined. Results: No association was observed between total or HMW adiponectin and BMDL2-L4 or TBBMC. On the contrary, adiponectin levels were positively associated with OPG levels (partial r=0.276, p=0.015) and negatively with IGF-I (partial r=-0.438, p<0.001), in multiple regression models after adjustment for potential confounders. HMW adiponectin showed a negative association with IGF-I (partial r=-0.266, p=0.049) in the multiple regression models but not with OPG, TBBMC or BMDL2-L4. Conclusions: Although we failed to show statistically significant association between circulating adiponectin levels and indices of bone mass in women during the postmenopausal period, we showed significant associations with OPG and IGF-I levels, suggesting an anabolic role of adiponectin, which may contribute in the understanding of the interplay between adipose tissue-derived hormones and bone metabolism. (J. Endocrinol. Invest. 35: 306-311, 2012) (C)2012, Editrice Kurtis