Hyperinsulinaemia, a key factor of the metabolic syndrome in postmenopausal women.

The metabolic syndrome (MetS) is a complex disorder combining obesity, hypertension, atherogenic dyslipidaemia and insulin resistance, a clustering of factors which markedly enhance the risk of developing cardiovascular disease (CVD) and type 2 diabetes. Main features of the MetS, which are found in many postmenopausal women, are increasing prevalence of insulin resistance and obesity (particularly visceral adiposity). Accordingly, a majority of postmenopausal women comply with criteria defining the MetS, and CVD is the first cause of morbidity/mortality in women, occurring even more frequently than in men. Moreover, obesity-related type 2 diabetes approaches pandemic proportions. Simultaneous occurrence of insulin resistance and obesity are most detrimental for metabolic health, and are also associated with increased oxidative stress, inflammatory and prothrombotic processes as well as with postmenopausal alterations in adipocytokine production. Hormone replacement therapy, provided the selected progestin does not antagonize estrogen action, may improve fat mass and distribution, dyslipidaemia and insulin sensitivity in postmenopausal women.