Type 2 diabetes and polycystic ovary syndrome
2006; Elsevier BV; Volume: 86; Linguagem: Inglês
10.1016/j.fertnstert.2006.04.010
ISSN1556-5653
Autores Tópico(s)Gestational Diabetes Research and Management
ResumoWomen with polycystic ovary syndrome (PCOS) have multiple factors that contribute to increased diabetes risk, including: insulin resistance, beta-cell dysfunction, obesity, especially centripetal obesity, family history of type 2 diabetes, and personal history of gestational diabetes. Additionally there is some evidence to suggest that polycystic ovaries and chronic anovulation per se are risk factors. Identifying glucose intolerance and treating it are important aspects of the care for women with PCOS. Women with polycystic ovary syndrome (PCOS) have multiple factors that contribute to increased diabetes risk, including: insulin resistance, beta-cell dysfunction, obesity, especially centripetal obesity, family history of type 2 diabetes, and personal history of gestational diabetes. Additionally there is some evidence to suggest that polycystic ovaries and chronic anovulation per se are risk factors. Identifying glucose intolerance and treating it are important aspects of the care for women with PCOS. Studies of large cohorts of women with polycystic ovary syndrome (PCOS) in the U.S. have demonstrated that the prevalence rates of glucose intolerance are as high as 40% in PCOS women when the less stringent WHO criteria are used (1Ehrmann D.A. Barnes R.B. Rosenfield R.L. Cavaghan M.K. Imperial J. Prevalence of impaired glucose tolerance and diabetes in women with polycystic ovary syndrome.Diabetes Care. 1999; 22: 141-146Crossref PubMed Scopus (1035) Google Scholar, 2Legro R.S. Kunselman A.R. Dodson W.C. Dunaif A. Prevalence and predictors of risk for type 2 diabetes mellitus and impaired glucose tolerance in polycystic ovary syndrome a prospective, controlled study in 254 affected women.J Clin Endocrinol Metab. 1999; 84: 165-169Crossref PubMed Scopus (1516) Google Scholar, 3Ehrmann D.A. Kasza K. Azziz R. Legro R.S. Ghazzi M.N. Effects of race and family history of type 2 diabetes on metabolic status of women with polycystic ovary syndrome.J Clin Endocrinol Metab. 2005; 90: 66-71Crossref PubMed Scopus (143) Google Scholar). These studies are of interest, because they have shown nearly identical rates of impaired glucose tolerance and type 2 diabetes among a diverse cohort, both ethnically and geographically. Undiagnosed diabetes based on 2-h glucose-challenged glucose levels approaches 10% in these cohorts. The majority of affected women are in their third and fourth decade of life, but we have encountered PCOS adolescents with impaired glucose tolerance or type 2 diabetes (4Palmert M.R. Gordon C.M. Kartashov A.I. Legro R.S. Emans S.J. Dunaif A. Screening for abnormal glucose tolerance in adolescents with polycystic ovary syndrome.J Clin Endocrinol Metab. 2002; 87: 1017-1023Crossref PubMed Scopus (268) Google Scholar) as well as lean individuals (body mass index <25) with glucose intolerance (2Legro R.S. Kunselman A.R. Dodson W.C. Dunaif A. Prevalence and predictors of risk for type 2 diabetes mellitus and impaired glucose tolerance in polycystic ovary syndrome a prospective, controlled study in 254 affected women.J Clin Endocrinol Metab. 1999; 84: 165-169Crossref PubMed Scopus (1516) Google Scholar). Based on the prevalence of glucose intolerance in women in the U.S. population, it can be extrapolated that PCOS contributes to approximately 20% of impaired glucose tolerance and 40% of type 2 diabetes in reproductive-aged women. It is important to note that these series report fasting normoglycemia in the majority of women and that, while elevated fasting levels tend to predict elevated 2-h glucose-challenged levels, even women with glucose intolerance tend to have fasting glucose levels below 100 mg/dL. This would suggest that these abnormalities may represent a universal characteristic of women with PCOS, at least those diagnosed on the basis of hyperandrogenic chronic anovulation. However rates of glucose intolerance and diabetes are substantially lower in a thinner European population with PCOS (5Gambineri A. Pelusi C. Manicardi E. Vicennati V. Cacciari M. Morselli-Labate A.M. et al.Glucose intolerance in a large cohort of mediterranean women with polycystic ovary syndrome phenotype and associated factors.Diabetes. 2004; 53: 2353-2358Crossref PubMed Scopus (145) Google Scholar), suggesting again that obesity further exacerbates diabetes risk. Natural history supportive of significant worsening of glucose tolerance would support more aggressive identification and treatment of this disorder in PCOS women. In other populations, impaired glucose tolerance (IGT) is a risk factor for the development of type 2 diabetes, with an average conversion rate of 1%–5% per year . There are certainly other groups of women at higher risk for developing type 2 diabetes, such as Latina women with a history of gestational diabetes, whose cumulative conversion rates to diabetes may be as high as 50% over 5 years, or 10% per year (6Kjos S.L. Peters R.K. Xiang A. Henry O.A. Montoro M. Buchanan T.A. Predicting future diabetes in Latino women with gestational diabetes. Utility of early postpartum glucose tolerance testing.Diabetes. 1995; 44: 586-591Crossref PubMed Google Scholar). To date, there have been several small published studies of conversion rates to diabetes over time in women with PCOS, and rates, while clinically meaningful, do not approach the magnitude found in other high-risk populations, such as women with gestational diabetes. Two studies have noted worsening glucose intolerance over time (1Ehrmann D.A. Barnes R.B. Rosenfield R.L. Cavaghan M.K. Imperial J. Prevalence of impaired glucose tolerance and diabetes in women with polycystic ovary syndrome.Diabetes Care. 1999; 22: 141-146Crossref PubMed Scopus (1035) Google Scholar). Body mass index at baseline was an independent significant predictor of conversion risk (7Norman R.J. Masters L. Milner C.R. Wang J.X. Davies M.J. Relative risk of conversion from normoglycaemia to impaired glucose tolerance or noninsulin dependent diabetes mellitus in polycystic ovarian syndrome.Hum Reprod. 2001; 16: 1995-1998Crossref PubMed Scopus (283) Google Scholar). In a similar-sized but controlled study with an average follow-up of 2.5 years, women with PCOS and IGT had a similar risk, with a net conversion of 6% to type 2 diabetes over approximately 3 years, or 2% per year (8Legro R.S. Gnatuk C.L. Kunselman A.R. Dunaif A. Changes in glucose tolerance over time in women with polycystic ovary syndrome a controlled study.J Clin Endocrinol Metab. 2005; 90: 3236-3242Crossref PubMed Scopus (236) Google Scholar). Although this was less than in the other populations noted above, the effect of PCOS was more pronounced in women with normal glucose tolerance at baseline, with a 40% conversion to IGT (Fig. 1). These small studies all suggest that abnormalities in glucose metabolism tend to increase with age in women with PCOS, and women with PCOS should be rescreened periodically.
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