Relationship between sex hormone-binding globulin levels and features of the metabolic syndrome

Contribution of age and declining androgen levels to features of the metabolic syndrome in men

Plasma dehydroepiandrosterone sulfate (DHEA-S) and testosterone levels both decline with age in healthy men. Features of the metabolic syndrome also show age-related deteriorations. We examined the relative contribution of age and declining androgen levels to features of the metabolic syndrome in men. In a sample of 130 nonsmoking men from the Quebec Family Study, we tested the hypothesis that age-related decreases in DHEA-S and testosterone levels would explain most of the variance in alterations of the metabolic profile associated with aging. As expected, we found that plasma DHEA-S and testosterone levels were negatively associated with age. Significant negative correlations were found between androgen levels and adiposity measures, body fat distribution, and metabolic risk variables. Statistical control for age eliminated correlations with DHEA-S, whereas age-adjusted associations between testosterone and most adiposity and metabolic variables remained significant. The percentage frequency of men characterized by 3 or more features of the metabolic syndrome increased with decreasing testosterone (8.9%-44.2%, chi2 = 15.89, P < .0005 ) and DHEA-S levels (8.9%-41.5%, chi2 = 13.02, P < .005). Logistic regression analyses showed that men in the upper tertile of testosterone levels had a lower risk of being characterized by 3 or more features of the metabolic syndrome (odds ratio = 0.24, P < .04) independent of age, whereas tertiles of DHEA-S levels were not related to the metabolic syndrome independent of age. In conclusion, results suggest that age per se is an important correlate of the associations between DHEA-S and metabolic variables, whereas the association of plasma testosterone levels to features of the metabolic syndrome appears to be independent of age.

The Metabolic Syndrome and Disturbances in Hormone Levels in Long-Term Survivors of Disseminated Testicular Cancer

Purpose

The metabolic syndrome may be an important risk factor for cardiovascular disease in long-term survivors of testicular cancer (TC). We investigated the associations between hormone levels and the metabolic syndrome in these men.

Patients and Methods

We included TC patients cured by orchidectomy and cisplatin-based chemotherapy, stage I TC patients after orchidectomy only, and healthy men of comparable age. Presence of the metabolic syndrome was determined using guidelines from the National Cholesterol Education Program Adult Treatment Panel III. Thyroid-stimulating hormone, follicle-stimulating hormone (FSH), inhibin B, luteinizing hormone (LH), total testosterone, sex-hormone–binding globulin, free testosterone, estradiol, dehydroepiandrosterone sulfate, and insulin-like growth factor 1 were determined in blood. Cortisol metabolite excretion was measured in urine.

Results

Eighty-six chemotherapy patients (median follow-up, 7 years) were compared with 44 stage I patients and 47 controls. LH and FSH were higher, and inhibin B and total and free testosterone were lower in chemotherapy patients than controls. Adrenal and thyroid hormone production were unaffected. Chemotherapy patients with the metabolic syndrome (n = 22; 26%) had a higher body mass index (BMI) pretreatment, a larger BMI increase during follow-up, lower total testosterone, and higher urinary cortisol metabolite excretion than those patients without the metabolic syndrome. BMI and insulin were associated with the metabolic syndrome, while total testosterone and urinary cortisol metabolite excretion were associated with BMI.

Conclusion

We found gonadal dysfunction, but normal adrenal and thyroid function. Through its association with BMI, testosterone may play a role in the development of the metabolic syndrome in long-term TC survivors.

Effects of oral and transdermal estradiol administration on levels of sex hormone-binding globulin in postmenopausal women with and without a history of intrahepatic cholestasis of pregnancy

SHBG, the most important transport protein for sex steroids, is produced in the liver under the control of estrogen action. In a randomized, double-blind, prospective crossover study we compared basal levels of serum SHBG and their responses to increasing doses of oral and transdermal estradiol (E2), followed by E2 plus oral progestin (medroxyprogesterone acetate [MPA]), in 40 postmenopausal women with or without a history of intrahepatic cholestasis of pregnancy (ICP), which could affect the synthesis of SHBG. Serum samples collected at baseline, on the last day of each E2 period, and on the last day of the E2 plus MPA combination were assayed for SHBG and E2. Basal levels of SHBG showed no difference between the study groups. Oral but not transdermal E2 increased SHBG concentrations by 67-171% in the control group, but the response was smaller (42-121%) in the ICP group. Addition of MPA decreased SHBG levels by 14-18% in both groups during both treatments. In conclusion, a history of ICP is associated with blunted responses of SHBG to oral estrogen.

Role of progestins with partial antiandrogenic effects

An experts' meeting on the 'Role of progestins with partial antiandrogenic effects' was held in Berlin from January 19 to 22, 2001. The meeting was chaired by Dr R. Sitruk-Ware (New York, USA) and participants included Ms F. Fruzzetti (Pisa, Italy), J. Hanker (Trier, Germany), J. Huber (Vienna, Austria), F. Husmann (Bad Sassendorf, Germany), S. O. Skouby (Copenhagen, Denmark), J. H. H. Thijssen (Utrecht, The Netherlands), and R. Druckmann (Nice, France). The present paper reports the conclusions of the meeting. However, the publication of the Women's Health Initiative study, which appeared after the meeting, led to additional comments and revisions.

Sex hormone-binding globulin is a major determinant of the lipid profile: the PRIME study

The prevalence of coronary heart disease is much higher in men than in women and sex hormones might play a role in these differences through their influence on the lipid profile. The aim of this cross-sectional study was to study the relationship between hormonal markers (total testosterone (TT), estradiol (E2), sex-hormone-binding globulin (SHBG)) and plasma lipids in a population-based sample. Subjects were 352 men, 50-59 years old, selected in France (Lille, Strasbourg and Toulouse) and Northern-Ireland (Belfast) who had questionnaires and a medical examination at baseline of the PRIME prospective study (1991-1993). Pearson correlation coefficients and Student's t tests were used to identify factors associated with plasma lipids. Multiple linear regression models were used for multivariate analyses, using triglycerides (TG) (log-transformed) and high density-lipoprotein cholesterol (HDL-C) as dependent variables. SHBG and TT were negatively correlated with TG (p<0.0001 and p<0.05, respectively) and positively correlated with HDL-C (p<0.0001 and p<0.01). E2 was positively correlated with TG (p<0.05). No significant association was found between sex-hormones and LDL-C. In multiple linear regression analyses, SHBG remained independently associated negatively with TG (p<0.01) and positively with HDL-C (p<0.0001) after adjustment for centre of recruitment, age, body mass index, systolic blood pressure, smoking, alcohol intake and physical activity. After further adjustment for insulin, the association between SHBG and HDL-C remained highly significant (p<0.0001). The association between SHBG and TG was weakened but remained also significant. Our results suggest that SHBG might to be a central protein in the hormonal regulation of the lipid profile.

Insulin resistance and alterations in angiogenesis: additive insults that may lead to preeclampsia

Altered angiogenesis and insulin resistance, which are intimately related at a molecular level, characterize preeclampsia. To test if an epidemiological interaction exists between these two alterations, we performed a nested case-control study of 28 women who developed preeclampsia and 57 contemporaneous controls. Serum samples at 12 weeks of gestation were measured for sex hormone binding globulin (SHBG; low levels correlate with insulin resistance) and placental growth factor (PlGF; a proangiogenic molecule). Compared with controls, women who developed preeclampsia had lower serum levels of SHBG (208+/-116 versus 256+/-101 nmol/L, P=0.05) and PlGF (16+/-14 versus 67+/-150 pg/mL, P<0.001), and in multivariable analysis, women with serum levels of PlGF < or =20 pg/mL had an increased risk of developing preeclampsia (odds ratio [OR] 7.6, 95% CI 1.4 to 38.4). Stratified by levels of serum SHBG (< or =175 versus >175 mg/dL), women with low levels of SHBG and PlGF had a 25.5-fold increased risk of developing preeclampsia (P=0.10), compared with 1.8 (P=0.38) among women with high levels of SHBG and low levels of PlGF. Formal testing for interaction (PlGFxSHBG) was significant (P=0.02). In a model with 3 (n-1) interaction terms (high PlGF and high SHBG, reference), the risk for developing preeclampsia was as follows: low PlGF and low SHBG, OR 15.1, 95% CI 1.7 to 134.9; high PlGF and low SHBG, OR 4.1, 95% CI 0.45 to 38.2; low PlGF and high SHBG, OR 8.7, 95% CI 1.2 to 60.3. Altered angiogenesis and insulin resistance are additive insults that lead to preeclampsia.