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

SHBG Levels Do Not Correlate with Insulin Levels in PCOS with Appropriate Fasting Insulin Sensitivity

Introduction: There are several phenotypes of polycystic ovarian syndrome (PCOS), and the different phenotypes may differ metabolically. Methods: In the present retrospective study, women with PCOS having normal fasting insulin sensitivity (n = 88) were compared with women with PCOS showing impaired insulin sensitivity (n = 46) using the HPCOS (Hungarian Polycystic ovarian syndrome) database. Results: The impaired insulin sensitivity group has significantly higher body mass index (BMI) and HOMA index than the normal fasting insulin sensitivity group (BMI (kg/m2): 22.0 vs. 28.1, p < 0.0001, HOMA index: 0.96 vs. 2.38, p < 0.0001). The sex hormone binding globulin (SHBG) level was significantly lower, and the free androgen index proved itself significantly higher in the impaired insulin sensitivity group (p < 0.05). Linear regression analysis showed a negative association of BMI with SHBG levels in both groups, while BMI had a positive correlation with insulin concentrations in both groups. However, the SHBG levels were negatively associated with insulin concentrations in the impaired insulin sensitivity group, but this inverse association could not be observed in the normal fasting insulin sensitivity group. Conclusions: The inverse linear correlation of SHBG with HOMA index and serum insulin level is not evident in all PCO syndrome phenotypes, thus SHBG has limited applicability for characterizing carbohydrate metabolism and serum insulin sensitivity.

Evaluation of the Efficacy of Sex Hormone-Binding Globulin in Insulin Resistance Assessment Based on HOMA-IR in Patients with PCOS

This study aimed to evaluate the efficacy of SHBG in predicting insulin resistance (IR) in newly diagnosed, untreated patients with polycystic ovary syndrome (PCOS). Hundred newly diagnosed, untreated patients with PCOS and 61 subjects without PCOS (41 healthy volunteers with normal BMI and 20 subjects with overweight/obese) were included in the study. Receiver-operating characteristic (ROC) analysis was used to assess the effectiveness of SHBG in predicting IR in overweight/obese and non-overweight PCOS patients and the optimal cut-off values of SHBG. The results showed negative correlations between log-SHBG and log-I₀ (r = - 0.372, P < 0.001) and log-SHBG and log-Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) (r = - 0.393, P < 0.001) after adjusting for blood pressure, serum lipid, age, and body mass index (BMI) in all of the PCOS patients. In patients with IR (defined as HOMA-IR ≥2.29), the area under the ROC curves (AUCs) of the SHBG for ROC analysis in the non-overweight group, overweight/obese group, and all PCOS patients were 0.774 (P = 0.0001), 0.922 (P = 0.0001), and 0.885 (P = 0.0001), respectively. The optimal cut-off value of SHBG was 37 nmol/L with a sensitivity of 97.62% and specificity of 80.85% in the overweight group. In patients with IR (HOMA-IR ≥2.5), the AUCs of SHBG for ROC analysis in the non-overweight group, overweight/obese group, and all PCOS patients were 0.741 (P = 0.0003), 0.928 (P = 0.0001), and 0.880 (P = 0.0001), respectively. The optimal cut-off value of SHBG was 30.2 nmol/L with a sensitivity of 97.44% and specificity of 82.69% in the overweight/obese group. In conclusion, this study observed a negative correlation between SHBG and HOMA-IR in PCOS patients after adjustment of confounding factors. SHBG was an independent influential factor of HOMA-IR and can be used as a positive predictive marker for IR in PCOS patients, especially in those who are overweight/obese.

Sex-specific Associations of Sex Hormone Binding Globulin with CKD and Kidney Function: A Univariable and Multivariable Mendelian Randomization Study in the UK Biobank

BACKGROUND

Kidney function declines faster in men. Testosterone levels may mediate the sex disparity. Correspondingly, levels of sex hormone binding globulin (SHBG), which modulates sex hormones, might also be relevant to the lower kidney function in men. The sex-specific role of SHBG is unclear.

METHODS

A sex-specific, Mendelian randomization (MR) study provided unconfounded estimates of SHBG levels among the United Kingdom Biobank population. Univariable MR applied 357 single nucleotide polymorphisms (SNPs) in men and 359 SNPs in women. These published SNPs strongly (P<5×10^-8) predict SHBG level. They were profiled in 179,916 white British men (6016 patients with CKD) and 212,079 white British women (5958 patients with CKD), to obtain the effect of SHBG on CKD, albuminuria, and eGFR. Multivariable MR controlling for testosterone was used to assess the effect of SHBG on CKD and kidney function independent of testosterone in men.

RESULTS

Genetically predicted higher SHBG was associated with a lower risk of CKD in men (odds ratio [OR], 0.78 per SD; 95% confidence interval [95% CI], 0.65 to 0.93) but had no benefit in women. The effect in men remained in multivariable MR, allowing for testosterone (OR, 0.61; 95% CI, 0.45 to 0.82).

CONCLUSIONS

Genetically predicted higher SHBG was associated with a lower risk of CKD and better kidney function in men, but not in women, suggesting that SHBG may play a role in CKD specifically in men. Identifying drivers of SHBG and the underlying pathways could provide new insights into CKD prevention and treatment.

Efficacy of sex hormone-binding globulin on predicting metabolic syndrome in newly diagnosed and untreated patients with polycystic ovary syndrome

PURPOSE

The aims of this study were to investigate the correlation of sex hormone-binding globulin (SHBG) and the components of metabolic syndrome (MetS) and explore the ability of SHBG to predict MetS in newly diagnosed and untreated patients with polycystic ovary syndrome (PCOS).

METHODS

Ninety-eight newly diagnosed and untreated patients with PCOS and 37 healthy volunteers were recruited. A receiver operating characteristic (ROC) curve was used to explore the best cutoff values of SHBG for predicting that the patients with PCOS would fulfill at least one abnormal index of MetS components, at least two abnormal indexes of MetS components, or MetS.

RESULTS

The numbers of patients with PCOS who fulfilled none, one, or two of the MetS criteria items and MetS were 33, 31, 19, and 15, respectively. SHBG was negatively correlated with BMI (r = - 0.615, P < 0.001), systolic blood pressure (SBP) (r = - 0371, P < 0.001), diastolic blood pressure (DBP) (r = - 0.285, P = 0.004), triglycerides (TG) (r = - 0.431, P < 0.001), fasting serum insulin (I₀) (r = - 0.549, P < 0.001), HOMA-IR (r = - 0.557, P < 0.001), and plasma glucose 2 h after glucose load (G₁₂₀) (r = - 0.337, P < 0.001) and positively correlated with high-density lipoprotein cholesterol (HDL-C) (r = 0.629, P < 0.001) in patients with PCOS. The optimal cutoff value of SHBG for predicting MetS in patients with PCOS was 21.3 nmol/L, with a sensitivity of 100.0% (95% CI 78.0-100.0%) and specificity of 85.12% (95% CI 77.5-90.9%).

CONCLUSIONS

Sixty-five patients had varying degrees of metabolic abnormalities, accounting for 66.3% of the patients with PCOS. SHBG was associated with metabolic indexes, including BMI, SBP, DBP, TG, I₀, HOMA-IR, G₁₂₀, and HDL-C, and can therefore be employed as a useful index for MetS prediction.

Endocrine factors associated with non-alcoholic fatty liver disease in women with polycystic ovary syndrome: do androgens play a role?

OBJECTIVE

To characterise the metabolic profile of women with polycystic ovary syndrome (PCOS) and non-alcoholic fatty liver disease (NAFLD) and to determine whether circulating androgens differ in PCOS women with NAFLD compared to PCOS subjects without NAFLD.

METHODS

Retrospective study of 21 women with PCOS, elevated liver enzymes and ultrasound evidence of hepatic steatosis matched with 32 PCOS women with normal liver enzymes. Extensive demographic, endocrine and metabolic data were compared. Pearson's correlation coefficients were calculated to assess for potential relationships between the free androgen index (FAI) and other dependent variables.

RESULTS

PCOS subjects with NAFLD demonstrate greater insulin resistance but have similar circulating androgen levels.

CONCLUSION

In this pilot study, insulin resistance was the most prominent feature characterising NAFLD complicating PCOS. Total testosterone, FAI, DHEAS and 17-hydroxyprogesterone levels were similar between patients with PCOS and without NAFLD.

Total ghrelin levels during acute insulin infusion in patients with polycystic ovary syndrome

Controversial data were reported concerning fasting ghrelin (decreased, normal or elevated) in polycystic ovary syndrome (PCOS). The aim of our study was to clarify ghrelin levels in non-obese, overweight, and obese PCOS patients; to investigate the effect of acute insulin infusion on ghrelin in PCOS as a chronic insulin-resistant state, with and without the impact of obesity, and to examine ghrelin-androgen interaction. In that order, we evaluated 1) ghrelin levels among 8 nonobese patients with PCOS [body mass index (BMI): 20.52+/-1.31 kg/m2], 8 overweight and obese patients with PCOS (BMI: 34.36+/-6.53 kg/m2) and their respective controls, 2) ghrelin suppression during euglycemic hyperinsulinemic clamp, and 3) ghrelin-androgen interrelationship. After overnight fast, 2-h euglycemic hyperinsulinemic clamp, was performed in all investigated women. Fasting ghrelin was significantly lower in non-obese PCOS than in controls (64.74+/-25.69 vs 108.36+/-52.60; p<0.05) as well as in overweight and obese PCOS in comparison with controls (38.71+/-14.18 vs 98.77+/-40.49; p<0.05). Insulin infusion significantly suppressed ghrelin in all subgroups of investigated women. Analysis of variance for repeatable measures confirmed that there was no significant difference in pattern of response between PCOS and controls. In conclusion, women with PCOS had lower fasting ghrelin and decreased insulin sensitivity independently of their BMI, compared to the controls. In addition, there were no differences between fasting ghrelin levels among non-obese, overweight, and obese women with PCOS. During euglycemic hyperinsulinemic clamp, ghrelin decreased in all studied groups to a similar extent, implying that, compared to chronic hyperinsulinemia, acute hyperinsulinemia reduces ghrelin levels independently of the degree of insulin resistance.