Comparative Study of Insulin Sensitivity and Resistance and Their Correlation with Androgens in Lean and Obese Women with Polycystic Ovary Syndrome

There is a lack of consensus on the optimal screening strategy for insulin resistance (IR), particularly in lean women with polycystic ovary syndrome (PCOS). Therefore, we conducted a cross-sectional study in 80 women with PCOS (28 lean/52 obese) and 80 age- and body mass index (BMI)-matched controls. Using a 5-point 75-g oral glucose tolerance test (OGTT) (0, 30, 60, 90, 120 min), we examined glucose and insulin excursions, IR, insulin sensitivity, beta-cell function (ss F), and the effect of androgens on IR. Lean and obese women with PCOS had similar glucose but higher insulin (except fasting in lean women) and insulin AUC as compared to their respective controls (p < 0.05). Lean women with PCOS were equally insulin-resistant but more hyperinsulinemic than the obese controls (p < 0.05). Although ss F ([1st phase: 481.71 +/- 263.53 vs. 430.56 +/- 232.37], [2nd phase: 815.16 +/- 447.12 vs. 752.66 +/- 428.95]) was comparable in lean and obese women with PCOS, lean women had better insulin sensitivity (112.78 +/- 66.26 vs. 75.49 +/- 55.6) (p < 0.05). Dehydroepiandrosterone sulfate (DHEAS) and androstenedione decreased with increasing BMI in lean women, and this correlated with deteriorating insulin sensitivity and exaggerated hyperinsulinemia. In obese women with PCOS, sex hormone-binding globulin (SHBG) correlated negatively with BMI and hyperinsulinemia, and positively with insulin sensitivity. This data suggests that estimating only fasting insulin may miss IR in lean women with PCOS; hence, additional time points in OGTT will add value to screening for IR. DHEAS and androstenedione may have a beneficial effect on insulin sensitivity and may be used to screen IR in lean women, while SHBG can be used as a predictive marker for IR in obese women with PCOS.