Serum sex hormone-binding globulin levels show too much variability to be used effectively as a screening marker for insulin resistance in women with polycystic ovary syndrome.
OBJECTIVE: To evaluate the relationship between serum sex hormone-binding globulin (SHBG) and parameters of insulin sensitivity in women with polycystic ovary syndrome (PCOS) and controls, and determine the feasibility of using SHBG levels to predict insulin resistance. DESIGN: Evaluation of a prospectively collected database. SETTING: University reproductive center. PATIENT(S): A total of 21 women with PCOS and 17 controls. INTERVENTION(S): Oral glucose tolerance test. MAIN OUTCOME MEASURE(S): Correlations of serum SHBG and parameters of insulin sensitivity. RESULT(S): [1] Among all participants, SHBG levels indicated a correlation between the fasting glucose-to-insulin (GI) ratio and the quantitative insulin sensitivity check index (QUICKI). Participants with PCOS demonstrated significant correlations of SHBG and fasting GI ratio, 1-hour postglucola insulin levels, and random 17-hydroxyprogesterone (17ohP4) levels. Among controls, SHBG and fasting serum glucose and 2-hour postglucola serum glucose levels were associated. [2] Participants with PCOS and lean controls exhibited different glucose and insulin responses to 75 g of glucose at 1 and 2 hours postchallenge, resulting in paradoxically similar GI ratios. CONCLUSION(S): [1] Although certain parameters of insulin status and serum SHBG demonstrated statistically significant correlation coefficients, these relationships are weak and SHBG cannot be used as a predictor of insulin resistance. [2] The post-glucose load GI ratio cannot be used to determine the magnitude of insulin resistance.