The transition to menopause reinforces adiponectin production and its contribution to improvement of insulin-resistant state

Objective: To evaluate the influence of menopausal status on the serum adiponectin concentration and investigate whether the contribution of adiponectin to insulin resistance is modified by menopausal status. Subjects: We conducted a population-based, cross-sectional study of 207 premenopausal and 206 postmenopausal Japanese women. Measurements: Data on anthropometric characteristics, fasting serum adiponectin, glucose and insulin concentrations were used. Insulin resistance (homeostasis model assessment of insulin resistance: HOMA-IR) was calculated. Results: Postmenopausal women had significantly higher HOMA-IRs than premenopausal women [1.50 (1.42, 1.59) vs 1.18 (1.12, 1.24), geometric mean (1 standard error range), P = 0.005]. Paradoxically, adiponectin levels in postmenopausal women were also significantly higher than those in premenopausal women [10.3 (9.95, 10.7) vs 9.04 (8.71, 9.39), P = 0.028]. Multiple regression analysis showed that body mass index (BMI) was the only significantly independent predictor [standardized partial regression coefficients (sβ) = 0.319, P < 0.001] for HOMA-IR among premenopausal women, whereas both BMI and adiponectin were the significant predictors among postmenopausal (sβ = 0.334 and -0.141, P < 0.001 and < 0.05, respectively). When the subjects were restricted to those without metabolic disorders including high blood pressure, hypertriglyceridaemia, hypo-HDL cholesterolaemia and high fasting glucose, adiponectin (sβ = -0.249, P < 0.05) was the only significant predictor for HOMA-IR among postmenopausal women but BMI was not significant (sβ = 0.223, P = 0.075). Conclusions: The transition to menopause increases serum adiponectin concentrations. And the significant and negative association between adiponectin and HOMA-IR was observed only after menopause. Therefore, adiponectin may play a role in the improvement of an incipient insulin-resistant state after, rather than before, menopause.