Role of adiponectin in mediating the association of osteocalcin with insulin resistance and type 2 diabetes: a cross sectional study in pre- and post-menopausal women

Objective: To analyse the association of osteocalcin with insulin resistance and type 2 diabetes and assess the role of adiponectin in these relationships. Methods: This study comprised 98 newly diagnosed type 2 diabetic women (51 pre-menopausal and 47 post-menopausal) and 102 age and BMI matched controls (53 pre-menopausal and 49 post-menopausal). Insulin resistance was calculated by homeostasis model assessment-insulin resistance (HOMA-IR). Results: Osteocalcin was significantly positively correlated with adiponectin in both pre-menopausal (p = 0.0026) and post-menopausal diabetic women (p = 0.0357). Significant negative association between osteocalcin and HOMA-IR was observed only in pre-menopausal diabetic women (p = 0.0019), but the association was partially reduced (p = 0.0219) after additional adjustment for adiponectin. Adiponectin slightly attenuated the inverse association between osteocalcin and presence of type 2 diabetes in both pre- and post-menopausal women. Conclusion: The protective action of osteocalcin against the development of insulin resistance and type 2 diabetes in women may be partially mediated through up-regulation of adiponectin secretion.