Adiponectin and bone mass density: The InCHIANTI study

Introduction: Adiponectin serum concentration has been reported to be inversely correlated with bone mineral density (BMD) in humans. The data on this issue, however, are biased by small study sample size and lack of controlling for body composition. Methods: We used data from the third follow-up of the InCHIANTI study, which included measurements of BMD using quantitative CT of the tibia and of body composition using bioimpedenziometry. Serum adiponectin was measured using radioimmunoassay. We excluded participants with diabetes, hyperthyroidism, using hormone replacement or corticosteroid therapy. We evaluated the correlation of adiponectin with total, trabecular, and cortical BMD using Pearson's coefficient, and linear regression models to estimate the association between adiponectin and BMD controlling for potential confounders (age, body mass index, alcohol intake, fat mass, smoking). Results: Our sample was made up of 320 men (mean age: 67. years, SD: 15.8, range: 29-97. years) and 271 postmenopausal women (mean age: 76. years, SD: 8.2, range: 42-97. years). In men, serum adiponectin was not independently associated with BMD. In women, after correction for potential confounders, adiponectin was associated with total (β= -0.626, P<0.001), trabecular (β= -0.696, P<0.001), and cortical (β= -1.076, P= 0.001) BMD. Conclusion: Our results show that adiponectin is inversely associated with bone mass in women. Further studies are needed to confirm these findings prospectively and then to clarify the explanatory mechanisms.