Type 2 diabetes and the polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a common endocrine disorder, affecting women in reproductive age, characterized by chronic anovulation and hyperandrogenism. The etiology of PCOS is still unknown. However, several studies have suggested that insulin resistance plays an important role in the pathogenesis of the syndrome. As a consequence of insulin-resistance, women affected by PCOS often present abnormalities of glucose metabolism and lipid profile, and have an increased risk of type 2 diabetes and cardiovascular disease over-time. Besides insulin-resistance, it has been demonstrated that some of these women also have alterations in beta-cell-function. Both disorders (insulin-resistance and beta-cell-dysfunction) are recognized as major risk factors for the development of type 2 diabetes. Long-term studies, evaluating the glucose-insulin system in women affected by PCOS, have shown a higher incidence of glucose intolerance, including both impaired glucose tolerance and type 2 diabetes, compared to age and weight matched control populations. The risk of glucose intolerance among PCOS subjects seems to be approximately 5 to 10 fold higher than normal and appears not limited to a single ethnic group. Moreover, the onset of glucose intolerance in PCOS women has been reported to occur at an earlier age than in the normal population (approximately by the 3rd-4th decade of life). However, other risk factors such as obesity, a positive family history of type 2 diabetes and hyperandrogenism may contribute to increasing the diabetes risk in PCOS.