Introduction: Adipocytokines have been proposed as new mediators of the protective effects of fat mass on the skeleton. The aim of this study was to test the relationship between adiponectin, leptin, and bone mineral density (BMD), independently of body composition, insulin resistance, and other factors known to affect bone metabolism.
Methods: Thirty-six post-menopausal non-diabetic elderly women, with ages ranging from 66 to 77 yr took part in the study. In all subjects we evaluated body weight, height, body mass index (BMI), waist circumference, adiponectin, leptin, insulin, DHEAS, and homeostasis model assessment of insulin resistance (HOMA), as well as yr since menopause. Total body fat mass (FM) and BMD at whole body and femoral level were measured with Dual energy X-ray Absorptiometry (DXA). Volumetric BMD was defined as the ratio between total body BMD and height.
Results: Leptin was positively and adiponectin negatively related with whole body and femoral BMD. Positive associations between insulin, HOMA, DHEAS, and BMD measures were also found. After adjusting for FM, only adiponectin maintained a significant relation with whole body and femoral BMD; the strength of this association was reduced after adjustment for insulin resistance, estimated by HOMA. In stepwise multiple linear regression analyses adiponectin explained 11.7% of total BMD variance, 17.4% of femoral neck BMD variance, and 30.7% of volumetric BMD variance, independently of BMI, FM, leptin, HOMA, and DHEAS.
Conclusions: The present study may suggest possible involvement of adiponectin in bone metabolism, independently of FM and insulin resistance even in elderly post-menopausal women.