Sex hormone-binding globulin as a marker for hyperinsulinemia and/or insulin resistance in obese children

Sex-specific differences in bone mineral density loss after sleeve gastrectomy

Background

Sleeve gastrectomy is an effective bariatric procedure; however, sleeve gastrectomy-related adverse skeletal outcomes have been increasingly reported. High levels of sex hormone-binding globulin (SHBG) have been documented to be a risk factor of bone mineral density (BMD) loss with different effects observed between sexes. The aim of this study was to identify sex-specific changes in BMD following sleeve gastrectomy and to evaluate the role of SHBG in this process.

Methods

This retrospective study included 19 middle-aged men and 30 non-menopausal women with obesity who underwent sleeve gastrectomy in China. Anthropometrics, bone turnover markers, calciotropic hormones, BMD, SHBG, and gonadal steroids were measured preoperatively and at 6 and 12 months postoperatively. Longitudinal changes in BMD, bone turnover markers and SHBG were compared between sexes by linear mixed models. Multiple stepwise regression analysis was used to identify the predictors of BMD loss at the investigated bone sites.

Results

Over the 12-month study period, total hip and femoral neck BMD decreased, while lumbar spine BMD remained largely unchanged in both sexes. Linear mixed models revealed significant sex × time interaction effects in total hip BMD and SHBG, showing that men had a significantly greater reduction in total hip BMD and less increase in SHBG after sleeve gastrectomy than women. In the multivariate model, SHBG was significantly associated with total hip BMD loss in men (adjusted β = −0.533, P = 0.019) but not women while total estrogen was significantly associated with total hip BMD loss in women (adjusted β = 0.508, P = 0.01) but not men.

Conclusion

Significant sex-specific BMD changes were observed after sleeve gastrectomy in the current study. Sleeve gastrectomy-related increase in SHBG may be a specific risk factor for total hip BMD loss in men. Our results indicate that sex-specific screening may be warranted to facilitate personalized postoperative bone care in this population.

The Relationship between Fat Mass Percentage and Glucose Metabolism in Children and Adolescents: A Systematic Review and Meta-Analysis

To assess the relationship between fat mass percentage (FMP) and glucose metabolism in children aged 0−18 years we performed a systematic review of the literature on Medline/PubMed, SinoMed, Embase and Cochrane Library using the PRISMA 2020 guidelines up to 12 October 2021 for observational studies that assessed the relationship of FMP and glucose metabolism. Twenty studies with 18,576 individuals were included in the meta-analysis. The results showed that FMP was significantly associated with fasting plasma glucose (FPG) (r = 0.08, 95% confidence interval (CI): 0.04−0.13, p < 0.001), fasting plasma insulin (INS) (r = 0.48, 95% CI: 0.37−0.57, p < 0.001), and homeostasis model assessment (HOMA)- insulin resistance (IR) (r = 0.44, 95% CI: 0.33−0.53, p < 0.001). The subgroup analysis according to country or overweight and obesity indicated that these associations remained significant between FMP and INS or HOMA-IR. Our results demonstrated that there is a positive relationship between FMP and FPG. Moreover, subgroup analysis according to country or overweight and obesity indicated that FMP is significantly associated with INS and HOMA-IR. This is the first known systematic review and meta-analysis to determine the associations of FMP with glucose metabolism in children and adolescents.

Sex Hormone Profile in Pubertal Boys With Gynecomastia and Pseudogynecomastia

CONTENT

Gynecomastia (defined by proliferation of glandular elements) and pseudogynecomastia (defined by adipose tissue) are frequent in pubertal boys. An association with sex hormones and the growth hormone axis has been discussed.

OBJECTIVE

The objective of this work is to compare sex hormones, insulin-like growth factor 1 (IGF-1), and insulin-like growth factor binding protein 3 (IGFBP-3) between boys with gynecomastia and pseudogynecomastia (separation by ultrasound).

DESIGN

An observational study was performed.

SETTING

The setting of this study was an outpatient clinic.

PARTICIPANTS

A total of 124 pubertal boys (mean age 14 ± 2 years) with breast enlargement and 84 healthy boys (mean age 14 ± 2 years) without breast enlargement participated in this study.

INTERVENTIONS

No interventions were performed.

MAIN OUTCOME MEASURES

Measurements were taken for sex hormones (progesterone, estradiol [E2], estriol, estrone, androstendione, testosterone [T], dihydrotestosterone) measured by liquid chromatography-tandem mass spectrometry, as well as gonadotropins, prolactin, IGF-1, and IGFBP-3.

RESULTS

Eighty-six boys suffered from gynecomastia and 38 from pseudogynecomastia. In boys with gynecomastia, the E2/T ratio (median 22, interquartile range [IQR] 8-75) was significantly (P < .05) higher compared to boys with pseudogynecomastia (median 12, IQR 5-21) or healthy controls without breast enlargement (median 18, IQR 6-44) even after adjustment for testes volume. T concentrations were significantly (P < .05) lower in boys with gynecomastia (median 1.8, IQR 0.7-4.2 nM/L) compared to boys with pseudogynecomastia (median 4.3, IQR 1.4-6.9 nM/L) or healthy controls without breast enlargement (median 3.1, IQR 0.6-7.6 nM/L). Boys with gynecomastia did not differ from boys with pseudogynecomastia according to other sex hormones, prolactin, IGF-1, or IGFBP-3 concentrations.

CONCLUSIONS

True gynecomastia is characterized by a relative T deficiency to E2 concentrations in contrast to pseudogynecomastia.

A cross-sectional survey of adrenal steroid hormones among overweight/obese boys according to puberty stage

BACKGROUND

Obesity is associated with many chronic diseases including cortisol rhythm disorder and low testosterone. Furthermore, studies on obese children are quite limited and no concordance results have been obtained, especially for boys in puberty. Moreover, the sample sizes of previous studies were small, and were not representative.

METHODS

We conducted a cross-sectional survey including 1148 boys aged 6-14 years, they were divided into overweight/obesity (OW/OB) group and normal weight (NW) group. Puberty status was assessed according to Tanner scale and testicular volume. Serum levels of pregnenolone, 17-OH progesterone, corticosterone, dehydroepiandrosterone (DHEA), and androstenedione were detected by LC-MS. Serum free testosterone and sex hormone-binding globulin (SHBG) levels were measured by chemiluminescence immunoassay.

RESULTS

The 17-OH progesterone, DHEA, androstenedione and free testosterone levels of OW/OB boys at prepubertal stage or at the age 6 = < 10 years group were higher than those of the NW boys (all the P values were < 0.01). Furthermore, androstenedione and free testosterone levels were lower in OW/OB boys at late puberty, and the trend continued at the post pubertal stage for FT (P < 0.01-0.05). DHEA, androstenedione, and FT levels persisted to be higher at the 10~ < 12 years in OW/OB boys but not for 17-OH progesterone. FT level was lower in the OW/OB group at the 12~ < 15 years group. The SHBG levels in the OW/OB boys were lower than those in the NW ones at the 6~12 years group, and prepubertal to early pubertal stage.

CONCLUSIONS

Premature adrenarche is more likely in OW/OB boys. More attention should be given to the lower androgen levels of OW/OB boys at late pubertal and post pubertal stages.

Obesity and breast cancer - Role of estrogens and the molecular underpinnings of aromatase regulation in breast adipose tissue

One in eight women will develop breast cancer over their lifetime making it the most common female cancer. The cause of breast cancer is multifactorial and includes hormonal, genetic and environmental cues. Obesity is now an accepted risk factor for breast cancer in postmenopausal women, particularly for the hormone-dependent subtype of breast cancer. Obesity, which is characterized by an excess accumulation of body fat, is at the origin of chronic inflammation of white adipose tissue and is associated with dramatic changes in the biology of adipocytes leading to their dysfunction. Inflammatory factors found in the breast of obese women considerably impact estrogen signaling, mainly by driving changes in aromatase expression the enzyme responsible for estrogen production, and therefore promote tumor formation and progression. There is thus a strong link between adipose inflammation and estrogen biosynthesis and their signaling pathways converge in obese patients. This review describes how obesity-related factors can affect the risk of hormone-dependent breast cancer, highlighting the different molecular mechanisms and metabolic pathways involved in aromatase regulation, estrogen production and breast malignancy in the context of obesity.

Cross-sectional study of the determinants and associations of sex hormone-binding globulin concentrations in first degree relatives (FDR) of patients with Type 2 Diabetes Mellitus

AIMS

This study explores the determinants of sex hormone binding globulin (SHBG) and associations with categories of glucose intolerance and undiagnosed diabetes in first-degree relatives (FDR) of patients with Type 2 Diabetes Mellitus (T2D).

METHODS

Anthropometric indices, fasting lipids, glucose, insulin, adiponectin, leptin, SHBG, estradiol (E2), testosterone (TT), androstenedione (AND), dehydroepiandrosterone sulphate (DHEA-S), high-sensitivity C-reactive protein (hs-CRP) and alanine aminotransferase (ALT) were measured in 584 FDR. Homeostasis model assessment-estimate of insulin resistance (HOMA-IR), beta cell function (%B), insulin sensitivity (%S) and free androgen index (FAI) were calculated.

RESULTS

266 subjects were normoglycemic; 237 had prediabetes and 81 had undiagnosed diabetes. SHBG decreased stepwise with worsening categories of glucose intolerance in females whereas FAI decreased stepwise with worsening categories in males only. SHBG showed significant positive correlations with adiponectin, and HDL-C and significant negative correlations with body mass index (BMI), waist circumference (WC), Waist:hip ratio (WHR), ALT, triglycerides (TG), %B, leptin and FAI. After adjustment for WHR, only HDL-C and FAI in men and FAI and HbA1c in females remained significantly associated with SHBG. Receiver Operating Characteristic (ROC) curve analysis for detection of diabetes showed that areas under the curve for FAI and SHBG were 0.711 and 0.386 for males and 0.430 and 0.660 for females respectively.

CONCLUSION

Associations of SHBG with some anthropometric and metabolic variables in FDR suggests that lower levels is a marker for risk of developing T2D through obesity dependent metabolic pathways but low FAI is a better marker of state of diabetes in males.

The association between skeletal maturation and adrenal androgen levels in obese children and adolescents

PURPOSE

This study aimed to investigate the association between skeletal maturation and adrenal androgen levels in obese children and adolescents.

METHODS

Fifty-three children and adolescents (aged 7-15 years) diagnosed as obese or overweight were investigated. Anthropometric measurements, bone age (BA) determination, serum biochemical analyses, and hormonal measurements were performed. The difference between BA and chronological age (BA-CA, dBACA) was calculated and used to represent the degree of advanced skeletal maturation.

RESULTS

Thirty-one subjects were classified into the obese group and 22 subjects into the overweight group. Insulin resistance as calculated by the homeostasis model assessment of insulin resistance (HOMA-IR) was significantly higher in the obese group than in the overweight group (4.03±2.20 vs. 2.86±1.11, P=0.026). The skeletal maturation of the obese group was advanced, but the dBACA did not differ between the obese and overweight groups statistically (1.43±1.35 vs. 0.91±1.15, P=0.141). Serum dehydroepiandrosterone sulfate (DHEA-S) levels were significantly higher in subjects with dBACA>1 compared to those with dBACA≤1 (104.3±62.2 vs. 59.6±61.0, P=0.014). Correlation analyses demonstrated that dBACA was positively correlated with body mass index standard deviation scores (r=0.35, P=0.010), fasting insulin (r=0.36, P=0.009), HOMA-IR (r=0.30, P=0.031), and insulin-like growth factor-binding protein-3 (r=0.331, P=0.028). In multivariate linear regression analysis, HOMA-IR (P=0.026) and serum DHEA-S (P=0.032) were positively correlated with the degree of advanced skeletal maturation.

CONCLUSION

Advanced skeletal maturation is associated with increased insulin resistance and elevated DHEA-S levels in obese children and adolescents.

Sex difference determined the role of sex hormone-binding globulin in obese children during short-term weight reduction program

The relationship between hyperinsulinemia and decreased sex hormone-binding globulin (SHBG) levels has been observed in obese adults and children. Weight reduction not only increased insulin sensitivity but also elevated serum SHBG levels in obese adults and children. However, the correlation between the changes in insulin resistance indices and serum SHBG concentration during weight reduction program (WRP) is not fully understood, particularly in obese children. This study is to evaluate whether SHBG level is a potential biomarker that can be used to assess insulin resistance in obese children during a short-term WRP. Forty-eight obese Taiwanese children (11.7 ± 2.2 years; 25 boys and 23 girls) participating in 8-week WRP were studied. Anthropometric measurements, lipid profiles, insulin resistance indices, and serum SHBG concentration were recorded at baseline and at the end of the WRP. The results showed body weight (BW), body mass index (BMI), body fat percentage (BF%), body fat weight (BFW), and insulin resistance indices such as fasting insulin, fasting insulin to glucose ratio, homeostasis model assessment (HOMA) of insulin resistance, log (HOMA) all significantly decreased after the 8-week WRP. With respect to lipid profiles, only high-density lipoprotein cholesterol (HDL-C) levels increased in both sexes. At baseline, insulin resistance indices were inversely correlated with SHBG concentrations in girls, but not in boys. The difference in SHBG after WRP was 2.58 nmol/L (95% confidence interval [CI]: -3.51, 8.66) in boys and 0.58 nmol/L (95% CI: -5.23, 6.39) in girls. There was a trend toward increased serum SHBG levels in boys (P = .39) and girls (P = .84) after weight loss, but a significantly negative correlation between the change in SHBG and in each of the insulin resistance indices only in the girls after adjusting age and ΔBFW during WRP.In conclusion, short-term WRP has the potential effects of decreased BW, BMI, BF%, and BFW, as well as increased serum HDL-C levels and insulin sensitivity in obese Taiwanese children. Although serum SHBG levels moderately increased in both sexes during short-term WRP, measuring the change in SHBG concentrations might be a potential biomarker to evaluate improvement in insulin resistance in girls only, and not in boys.

The Mechanisms and Effects of Physical Activity on Breast Cancer

Breast cancer is the most common cancer in women. An extensive part of this health problem can be prevented by an active lifestyle. Physical activity can reduce the risk of breast cancer, reduce the rate of recurrence, and increase the survival rate of patients with breast cancer. The aim of this review was to summarize our current knowledge regarding the effects of physical activity on breast cancer risk, recurrence, and survival. Furthermore, we investigated 5 possible underlying mechanisms through which physical activity has an influence on breast cancer (ie, a reduction of sex hormones, metabolic hormones, adipokines and oxidative stress, and an improvement of the immune function). In this review, we give a complete overview of this subject.

Sex Hormone-Binding Globulin in Children and Adolescents

Sex hormone-binding globulin (SHBG) is a circulating glycoprotein that transports testosterone and other steroids in the blood. Interest in SHBG has escalated in recent years because of its inverse association with obesity and insulin resistance, and because many studies have linked lower circulating levels of SHBG to metabolic syndrome, type 2 diabetes, nonalcoholic fatty liver disease, polycystic ovary syndrome, and early puberty. The purpose of this review is to summarize molecular, clinical, endocrine, and epidemiological findings to illustrate how measurement of plasma SHBG may be useful in clinical medicine in children.

Gender-specific associations of serum sex hormone-binding globulin with features of metabolic syndrome in children

BACKGROUND

Sex hormone-binding globulin (SHBG) has been proposed as a biomarker of MetS in children and adults. We aim to determine the associations of SHBG with components of MetS in children from the Middle-East where the prevalence of MetS are on the rise.

METHODS

In this cross-sectional study, a total of 509 randomly selected school children (226 boys and 283 girls) aged 12-16 years were recruited. Fasting blood glucose and lipid profile were determined using routine laboratory procedures. Serum SHBG is measured with Cobas e411 using an electrochemiluminescence immunoassay. The modified definition of ATP-III (NHANES III) was used for the diagnosis of MetS.

RESULTS

Among 509 children, 23.4 % had metabolic syndrome. Boys had a significantly higher waist circumference and systolic blood pressure (p < 0.032, 0.024, respectively) than girls, while levels of glucose (p < 0.029), and SHBG (p < 0.003) were significantly higher in girls than in boys. In overall population, a significant inverse correlation of SHBG level with age, BMI, systolic blood pressure and triglycerides and a significant direct correlation between SHBG level and HDL-c was exhibited. Children with the lowest tertile of serum SHBG had significantly higher prevalence of MetS (p < 0.05). ROC curve shows SHBG level as more sensitive marker of MetS in boys (AUC = 0.70, p < 0.001).

CONCLUSIONS

Serum SHBG is significantly more sensitive in identifying MetS in boys, not girls, indicating gender dimorphism.

Obesity, maternal smoking and SHBG in neonates

BACKGROUND

Sex hormone binding globulin (SHBG), a glycoprotein produced by hepatocytes that transports testosterone and other steroids in plasma, is a marker for developing metabolic syndrome and T2DM. SHBG is present in umbilical cord blood where it may be epigenetically regulated. This study was conducted to investigate whether the fetal environment, based on maternal pre-pregnancy weight, pregnancy weight gain or smoking during pregnancy, influence SHBG in newborns.

METHODS

Maternal and newborn characteristics and SHBG levels and other variables were measured in cord and day 2 heel-stick blood samples in 60 healthy full-term singleton babies (31 F, 29 M).

RESULTS

SHBG levels varied nearly fivefold among male and female newborns and were unrelated to sex, neonatal adiposity, determined by the Ponderal index and skinfold thickness, nor TNF∝ in cord blood. There were also no statistically significant associations between pre-pregnancy weight or pregnancy weight gain and newborn SHBG levels. However, cord blood SHBG was higher and insulin levels were lower when mothers were smokers, but normalized by day 2.

DISCUSSION

While SHBG levels are low in obese children and adults, and portend the development of metabolic syndrome and T2DM, our study of healthy babies born to normal women, found no connection between maternal obesity or newborn adiposity and SHBG levels in newborns. Insofar as women who smoked during pregnancy were thinner and had lower cord blood insulin levels than nonsmokers, higher SHBG in their newborns at birth might have been due to insulin sensitivity, or perhaps to an effect of smoking on placental gene expression.

CONCLUSIONS

Factors other than maternal weight and pregnancy weight gain appear to be the major determinants of SHBG in newborns. Higher SHBG levels when mothers smoke during pregnancy may contribute to overweight beginning later in childhood. Whether newborn SHBG levels predict the development of overweight and metabolic syndrome remains to be determined.

Evidence of male hypogonadism at an early age as a familial risk of type 2 diabetes

OBJECTIVE

Previous investigations provide evidence of an association of hypogonadism with type 2 diabetes in men, and low testosterone levels have been regarded a risk factor for the disease. Since a strong genetic predisposition to type 2 diabetes has been demonstrated, here we investigate a possible tendency towards hypogonadism in young male offspring of diabetic parents.

MATERIAL AND METHODS

The study compares 32 male offspring of diabetic parents with 31 male offspring of nondiabetic parents matched by age. The subjects comprised boys (9-17 years) and young adults (19-25 years). Anthropomorphic measurements were made in all subjects. Fasting blood samples were analyzed for glucose and serum concentrations of testosterone (T), sex hormone-binding globulin (SHBG), luteinizing hormone (LH), insulin and leptin were measured by ELISA. Free testosterone (FT) was calculated using T and SHBG levels.

RESULTS

Serum T, FT and bioavailable T (BAT) levels in offspring of diabetic parents were significantly lower than those of offspring of nondiabetic parents across all age groups. Mean serum LH levels were also lower in offspring of diabetic parents compared to the controls. Although LH levels in young adults with diabetic parents, tended to be lower than those of age-matched controls but the difference was not statistically significant. Serum insulin and leptin, and insulin resistance measured by HOMA-IR were significantly raised in older offspring of diabetic parents but were within the normal range.

CONCLUSION

Whereas hypogonadism was the only indicator of a possible predisposition to metabolic dysfunction in peripubertal children of diabetic parents, a significant change in other metabolic markers becomes apparent at a more advanced age.

Body Mass Index Is Associated with Impaired Semen Characteristics and Reduced Levels of Anti-Müllerian Hormone across a Wide Weight Range

There is still controversy as to how body mass index (BMI) affects male reproduction. We investigated how BMI is associated with semen quality and reproductive hormones in 166 men, including 38 severely obese men. Standard semen analysis and sperm DNA integrity analysis were performed, and blood samples were analysed for reproductive hormones. Adjusted for age and time of abstinence, BMI was negatively associated with sperm concentration (B = -0.088, P = 0.009), total sperm count (B = -0.223, P = 0.001), progressive sperm motility (B = -0.675, P = 0.007), normal sperm morphology (B = -0.078, P = 0.001), and percentage of vital spermatozoa (B = -0.006, P = 0.027). A negative relationship was observed between BMI and total testosterone (B = -0.378, P < 0.001), sex hormone binding globulin (B = -0.572, P < 0.001), inhibin B (B = -3.120, P < 0.001) and anti-Müllerian hormone (AMH) (B = -0.009, P < 0.001). Our findings suggest that high BMI is negatively associated with semen characteristics and serum levels of AMH.

Androgens and obesity in male adolescents

PURPOSE OF REVIEW

Data on sex steroid levels and pubertal development in obese adolescent boys are scarce and contrasting. The present review summarizes the most recent results obtained with improved methodology to measure low sex steroid levels in children.

RECENT FINDINGS

Obese pubertal boys have lower serum sex hormone-binding globulin and consequently lower total testosterone levels compared to normal-weight peers. However, during pubertal development, free testosterone levels in obese adolescents are not different from controls, indicating preserved androgen exposure as is additionally suggested by similar clinical genital staging (Tanner), serum gonadotropins levels, and serum prostate-specific antigen concentrations compared to nonobese adolescents. In pre and early puberty, total testosterone levels is not decreased, notwithstanding low sex hormone-binding globulin, and free testosterone is slightly increased in obese boys. This may result from increased adrenal activity as revealed by elevated serum androstenedione and dehydroepiandrosterone sulfate. In obese adolescent boys, increased aromatization of testosterone to estradiol tends to accelerate skeletal maturation.

SUMMARY

In obese adolescent boys, free testosterone is a better index than total testosterone levels of androgen status, which is not different from nonobese controls. Increased aromatization of testosterone to estradiol underlies the dissociation between normal clinical sexual maturation and advanced skeletal maturation in the obese adolescent.

Sex hormone-binding globulin gene expression and insulin resistance

CONTEXT

The plasma level of sex hormone binding globulin (SHBG), a glycoprotein produced by hepatocytes, is subject to genetic, hormonal, metabolic, and nutritional regulation, and is a marker for the development of the metabolic syndrome and diabetes.

OBJECTIVE

Because the mechanism for these associations is unclear, and no studies of SHBG gene expression in humans have been published, SHBG mRNA was measured in human liver samples and related to anthropometric data.

SETTING

Inpatients at a private, nonprofit, university-associated hospital were studied.

PARTICIPANTS

Subjects were fifty five adult men and women undergoing hepatic resection as treatment for cancer.

MAIN OUTCOME MEASURES

Main outcome measures were SHBG mRNA and serum SHBG levels.

RESULTS

SHBG mRNA was a strong predictor of serum SHBG with higher levels of the mRNA and protein in women than in men. The relationship between SHBG mRNA and circulating SHBG differed in males and females consistent with a sex difference in post-transcriptional regulation. A strong positive correlation was found between the level of the mRNA for the transcription factor HNF4α and SHBG mRNA. Insulin resistance (IR), assessed by homeostatis model assessment, was related inversely to SHBG mRNA and to HNF4α mRNA as well as to circulating SHBG levels. These mRNAs, as well as serum SHBG, were higher when the hepatic triglyceride concentration was low, and decreased with increasing body mass index but were unrelated to age.

CONCLUSIONS

Fat accumulation in liver and IR are important determinants of SHBG gene expression and thereby circulating SHBG levels that are perhaps mediated through effects on the transcription factor HNF4α. These findings provide a potential mechanism to explain why low SHBG predicts the development of type 2 diabetes.

Plasma non-esterified fatty acid levels in children and their relationship with sex steroids

OBJECTIVE

Puberty is associated with decreased insulin sensitivity. Sexual hormones have been related with the onset of insulin resistance, but their relationship with non-esterified fatty acids (NEFA) remains unexplored. The aim of this study was to evaluate circulating NEFA levels in population-based samples of prepubertal children and adolescents and to analyze the association of NEFA with obesity, insulin resistance, and sexual hormones in adolescents.

EXPERIMENTAL

The studied population included 854 randomly selected 6-8-year-old children and 822 children aged 12-16years. NEFA levels were determined using a commercial kit. Testosterone and estradiol levels were determined by RIA, and insulin and sex hormone binding protein by IRMA. HOMA was calculated as an indicator of insulin resistance.

RESULTS

NEFA levels were lower in adolescents than in 6-8-year-old children, and decreased progressively with age between 12-year-olds and 16-year-olds. No significant differences in NEFA levels were observed between obese and non-obese adolescents. NEFA were not correlated with insulin or HOMA in 12-16-year-old girls, and appear negatively correlated with these variables in boys. Insulin and HOMA were negatively correlated with SHBG levels in both sexes adjusting by age but NEFA levels were not.

CONCLUSIONS

NEFA levels decrease with age in adolescents and are not significantly increased in obese children, supporting the fact that the decreased insulin sensitivity at this age is not affecting NEFA metabolism. Although SHBG is related to insulin and HOMA independently of age in both sexes, SHBG levels are not associated with NEFA.

Sex steroids in relation to sexual and skeletal maturation in obese male adolescents

BACKGROUND

Childhood obesity is associated with an accelerated skeletal maturation. However, data concerning pubertal development and sex steroid levels in obese adolescents are scarce and contrasting.

OBJECTIVES

To study sex steroids in relation to sexual and skeletal maturation and to serum prostate specific antigen (PSA), as a marker of androgen activity, in obese boys from early to late adolescence.

METHODS

Ninety obese boys (aged 10-19 y) at the start of a residential obesity treatment program and 90 age-matched controls were studied cross-sectionally. Pubertal status was assessed according to the Tanner method. Skeletal age was determined by an x-ray of the left hand. Morning concentrations of total testosterone (TT) and estradiol (E2) were measured by liquid chromatography-tandem mass spectrometry, free T (FT) was measured by equilibrium dialysis, and LH, FSH, SHBG, and PSA were measured by immunoassays.

RESULTS

Genital staging was comparable between the obese and nonobese groups, whereas skeletal bone advancement (mean, 1 y) was present in early and midadolescence in the obese males. Although both median SHBG and TT concentrations were significantly (P < .001) lower in obese subjects during mid and late puberty, median FT, LH, FSH, and PSA levels were comparable to those of controls. In contrast, serum E2 concentrations were significantly (P < .001) higher in the obese group at all pubertal stages.

CONCLUSION

Obese boys have lower circulating SHBG and TT, but similar FT concentrations during mid and late puberty in parallel with a normal pubertal progression and serum PSA levels. Our data indicate that in obese boys, serum FT concentration is a better marker of androgen activity than TT. On the other hand, skeletal maturation and E2 were increased from the beginning of puberty, suggesting a significant contribution of hyperestrogenemia in the advancement of skeletal maturation in obese boys.

Intensive insulin therapy increases sex hormone-binding globulin in newly diagnosed type 2 diabetic patients

OBJECTIVE

Many studies have shown that low sex hormone-binding globulin (SHBG) is associated with insulin resistance, but only few studies have examined how serum SHBG is regulated by insulin in humans. This interventional study aimed to investigate the effect of insulin therapy (IT) on serum SHBG levels in newly diagnosed type 2 diabetic patients.

METHODS

A total of 80 newly diagnosed type 2 diabetic subjects were enrolled and randomly grouped into a 2-week intensive IT with/without metformin. Serum SHBG, total testosterone, glucose, liver enzymes, lipids, insulin, and C-peptide levels were measured before and after IT.

RESULTS

Before IT, serum SHBG levels were negatively correlated with BMI, waist circumference (WC), alanine aminotransferase (ALT), gamma-glutamyl transpeptidase (γ-GT), triglyceride (TG), fasting insulin, and C-peptide, and homeostatic model assessment of insulin resistance (HOMA-IR), and positively with HDL-C (all P for trend <0.05), after adjustment for age and sex. IT increased serum SHBG levels from 26.5±14.5 to 33.2±15.0 nmol/l (P<0.001), increased by 25.2% (95% CI, 20.3 to 30.9%, P<0.001). In a multiple linear regression model adjusting for age, sex, BMI, and WC, the decreases in ΔALT (standardized regression coefficient β=-0.374, P=0.012) and ΔTG (β=-0.380, P=0.020) were independent contributors to the increase in ΔSHBG.

CONCLUSIONS

IT increases serum SHBG likely through improving insulin resistance and liver function.

Role of sex steroids, intrahepatic fat and liver enzymes in the association between SHBG and metabolic features

BACKGROUND

SHBG and liver enzymes levels are both associated with the risk of type 2 diabetes. However, the relationship between SHBG with liver enzymes and intrahepatic fat content remain poorly understood.

OBJECTIVE

To investigate whether SHBG is correlated with glucose and lipids levels and whether this association depends on fatty liver content, liver enzymes or sex hormone concentrations.

DESIGN AND PATIENTS

We studied 233 dysmetabolic men with measures of plasma SHBG, total testosterone, 17β-oestradiol, glucose, adiponectin, liver enzymes and hepatokines. Intrahepatic liver fat and visceral fat contents were measured by magnetic resonance imaging in 108 of these individuals.

RESULTS

After adjustment for age, SHBG concentration was inversely correlated with fasting glucose (βstandardized  = -0·21, P = 0·0007), HbA1c (βstandardized  = -0·27, P < 0·0001), triglycerides (βstandardized  = -0·19, P = 0·003) and positively correlated with HDL-Cholesterol (βstandardized  = 0·14, P = 0·03). These correlations persisted after adjustment for either total testosterone or 17β-oestradiol levels. SHBG was not related to either fetuin A or FGF 21 concentrations. The inverse association of SHBG with HbA1c and glycaemia was not altered after adjusting for liver markers but was no longer significant after adjustment for hepatic fat content.

CONCLUSION

The significant association between SHBG and fasting glycaemia, HbA1c and lipid levels in dysmetabolic men was not related to either sex hormones or markers of liver function, but was dependent on intrahepatic fat. This suggests that intrahepatic fat, but not alterations in liver function markers, may be involved in the association between SHBG and glucose and lipid metabolism.

Steroid hormone profiles in prepubertal obese children before and after weight loss

CONTEXT

Little information is available on the steroid hormone profiles in obese children and their changes after weight loss.

OBJECTIVE

We compared liquid chromatography-tandem mass spectrometry of serum steroid hormone profiles between obese and normal-weight children and studied the differential effects of weight loss on these hormones.

DESIGN

This study was a cross-sectional comparison between obese and normal-weight children and a longitudinal 1-year follow-up study during lifestyle intervention in obese children.

SETTING

The setting of the study was primary care.

PATIENTS

Forty obese prepubertal (mean age 8.5 ± 2.1 years, 48% female, mean body mass index 24.8 ± 3.5 kg/m(2)) and 40 normal-weight children matched for gender, age, and pubertal stage.

INTERVENTION

The study consisted of an outpatient 1-year intervention program based on exercise, behavior, and nutrition therapy.

MAIN OUTCOMES MEASURES

Progesterone, 17-hydroxyprogesterone, 11-deoxycorticosterone, corticosterone, aldosterone, 11-deoxycortisol, cortisol, cortisone, dehydroepiandrosterone sulfate (DHEAS), androstenedione, T, dihydrotestosterone, insulin resistance index of the homeostasis model assessment, and blood pressure were measured.

RESULTS

Prepubertal obese children showed significantly increased androgens (DHEAS, androstenedione, T), mineralocorticoid precursor corticosterone, and glucocorticoids (11-deoxycortisol, cortisol, cortisone) compared with normal-weight children. In contrast to 20 obese children without weight loss, the 20 obese children with substantial weight loss demonstrated a significant decrease of cortisol, cortisone, and corticosterone. Androstenedione and T decreased but DHEAS remained elevated. Changes of the homeostasis model assessment correlated significantly positively with changes of cortisol (r = 0.38) and cortisone (r = 0.43) in partial regression analyses adjusted to changes of weight status.

CONCLUSIONS

In obese prepubertal children, the increased androgens, mineralocorticoid precursors, and glucocorticoids were responsive to weight loss in contrast to DHEAS, suggesting that DHEAS does not seem to be regulated by changes in body mass index.

Sex hormone-binding globulin and the risk for metabolic syndrome in children of South Asian Indian origin

OBJECTIVE

To determine whether the plasma level of sex hormone-binding globulin (SHBG) identifies South Asian Indian children at risk for metabolic syndrome.

METHODS

Adults and their children aged 5 to 9 years were recruited at the annual health fair at the Hindu temple serving the South Asian Indian community in Louisville, Kentucky. Anthropometric data were collected in adults and children, and blood pressure, lipid, and glucose levels were measured in adults. SHBG levels were measured in children using a fingerstick blood sample. In adults, metabolic syndrome was diagnosed according to the International Diabetes Federation criteria. Twelve months later, follow-up anthropometric data were obtained for a portion of the children.

RESULTS

The study included 30 sets of parents and 30 children. The prevalence of metabolic syndrome among 310 adults attending the health fair was 42% in men and 39% in women. Children with 1 parent with metabolic syndrome had 24% lower SHBG levels that increased to 55% if both parents had metabolic syndrome. SHBG levels were inversely related to waist circumference and to body mass index percentile. Both SHBG and waist circumference predicted weight gain over 1 year in children. CONCLUSIONS Low SHBG levels were found in South Asian Indian children whose parents had attributes of metabolic syndrome. The dose dependency of SHBG is consistent with inheritance of a genetic trait, and if the results are applicable to other racial/ethnic groups, SHBG may be a useful marker to identify at-risk children for early intervention.

Distinct metabolic surrogates predict basal and rebound GH secretion after glucose ingestion in men

CONTEXT

GH secretion declines rapidly after glucose ingestion and then recovers to higher-than-baseline levels (rebound GH release).

HYPOTHESIS

Selective metabolic markers predict the magnitude of glucose-suppressed GH release and postglucose rebound-like GH secretion.

DESIGN

Prospectively randomized crossover study of GH secretion after glucose vs. water ingestion.

SETTING

The study was conducted at a clinical translational research center.

PARTICIPANTS

Sixty-nine healthy men aged 19-78 yr with a body mass index of 18-39 kg/m(2) participated in the study.

OUTCOMES

OUTCOMES included nadir vs. peak GH concentrations and basal vs. pulsatile GH secretion.

RESULTS

Mean nadir GH concentrations were determined positively by sex hormone binding globulin (SHBG) after glucose administration (R(2) = 0.088, P = 0.0077). Peak rebound GH concentrations were related positively to adiponectin and negatively to computed tomography-estimated abdominal visceral fat (AVF) (R(2) = 0.182, P = 0.00049) after glucose ingestion. Deconvolution analysis showed that SHBG specifically predicted basal (nonpulsatile) GH secretion after glucose exposure (R(2) = 0.153, P = 0.00052). In contrast, together exercise history and adiponectin (both positively) and AVF (negatively) predicted pulsatile GH escape after glucose suppression (R(2) = 0.206, P = 0.00043). Moreover, adiponectin uniquely determined the size (mass), and AVF the mode (duration), of GH secretory bursts after glucose exposure (both P < 0.006).

CONCLUSION

Glucose ingestion provides a clinical model for investigating complementary metabolic surrogates that determine suppression and recovery of basal and pulsatile GH secretion in healthy men.

Effect of weight reduction on insulin sensitivity, sex hormone-binding globulin, sex hormones and gonadotrophins in obese children

OBJECTIVE

Obesity in men is associated with reduced insulin sensitivity and hypoandrogenism, while obesity in women is associated with reduced insulin sensitivity and hyperandrogenism. In children, the effect of obesity and weight reduction on the hypothalamo-pituitary-gonadal axis is rarely investigated. The aim of the present study was to investigate the effect of weight reduction in obese Caucasian children on insulin sensitivity, sex hormone-binding globulin (SHBG), DHEAS and the hypothalamo-pituitary-gonadal axis.

METHODS

One hundred and sixteen (65 females) obese children with a median age of 12.3 (7-15) years were examined before and after a 10-week stay at a weight loss camp. Examination included anthropometry and fasting blood samples measuring plasma glucose, serum insulin, SHBG, DHEAS, testosterone, 17β-oestradiol, FSH and LH.

RESULTS

Body mass index (BMI) decreased (P<0.01), insulin sensitivity and SHBG increased (P<0.01), independent of gender and puberty. The changes in insulin sensitivity and the changes in SHBG correlated significantly (P<0.01) independent of gender, puberty and the changes in BMI. Testosterone increased in boys (P<0.01) and tended to decrease in girls (P=0.05, in girls after menarche (P=0.03)). FSH increased in boys and girls. LH increased in boys and was unchanged in girls.

CONCLUSIONS

During weight loss, insulin sensitivity and SHBG increased significantly in obese children, and the changes in insulin sensitivity and the changes in SHBG correlated significantly independent of gender, puberty and the changes in BMI. There was sexual dimorphism in the changes of testosterone, with the changes in boys towards increased virilisation and the changes in girls towards less virilisation.

Sex hormone-binding globulin levels and metabolic syndrome and its features in adolescents

BACKGROUND

Low levels of sex hormone-binding globulin (SHBG) are associated with obesity, insulin resistance, and metabolic syndrome (MS) in men and women, and it has been suggested that SHBG could be a useful marker for MS risk.

OBJECTIVE

The aim of this study was to analyze the relationship of SHBG levels with MS and its components in Spanish adolescents.

METHODS

The sample population of this cross-sectional study was comprised of 386 male and 429 female adolescents, aged 12-16 yr. Anthropometric parameters and blood pressure (BP) were measured. Total cholesterol, high-density lipoprotein (HDL)-cholesterol, insulin, glucose, and SHBG levels were determined. The pediatric International Diabetes Federation (IDF) definition was used to classify adolescents for MS.

RESULTS

SHBG levels were lower in adolescents with MS or with some MS features. More than 90% of the abdominally obese adolescents were in the lowest and medium SHBG tertiles. In girls, BP was significantly higher in the lowest SHBG tertile than in the two others, whereas in boys BP levels were significantly higher in the lowest and medium tertiles than in the highest one. Insulin levels and homeostasis model assessment (HOMA) index were also significantly higher in the lowest SHBG tertile than in the two others.

CONCLUSIONS

The associations of SHBG with MS and its components, such as abdominal obesity, high BP or insulin levels, are already present in normal adolescents. This may suggest the possibility of using SHBG levels as a biomarker for MS risk in adolescents as well as adults.

SHBG levels correlate with insulin resistance in postmenopausal women

BACKGROUND

Overweight or central obesity is generally associated with increases in fasting insulin levels, insulin resistance, and glucose intolerance and has been identified as a target for new therapeutic strategies, including early change in lifestyle. Early biochemical markers for identifying at-risk patients will be useful for prevention studies. The aim of this study is to investigate whether or not SHBG level is a useful index of hyperinsulinemia and/or insulin resistance in pre- and postmenopausal obese women. At the same time, the relationship between SHBG concentrations and features of the metabolic syndrome were evaluated.

METHODS

229 women were eligible for this study. MetS was defined by using a modification of the ATP III guidelines. All patients were euthyroid, obese and overweight, 25 to 69 years of age. Subjects were divided into groups of premenopausal women (n=125) and postmenopausal women (n=104). Various fatness and fat distribution parameters, SHBG, sex hormones, FSH, LH, thyroid hormones, serum levels of fasting and postprandial glucose, lipid profile, uric acid and serum insulin, and blood pressure were measured.

RESULTS

No significant difference was found in mean SHBG levels between pre- and postmenopausal obese women in this study (p=0.866). In premenopausal obese women, SHBG correlated negatively with BMI, waist circumference, fasting glucose, uric acid levels and FAI. In postmenopausal obese women, SHBG correlated negatively with fasting glucose, postprandial plasma glucose, fasting insulin, HOMA-IR and FAI and positively with HDL. SHBG had a significant inverse association with MetS parameters only in postmenopausal women, also after adjusting for BMI, age and estradiol.

CONCLUSIONS

Obesity may influence the levels of endogenous sex steroid, especially after menopause. SHBG concentrations are correlated with features of the metabolic syndrome, particularly in postmenopausal obese women. These results suggest that SHBG may be an index of insulin resistance in postmenopausal obese women.

Serum sex hormone-binding globulin levels in healthy children and girls with precocious puberty before and during gonadotropin-releasing hormone agonist treatment

CONTEXT

The regulation of SHBG is complex and influenced by sex steroids and insulin.

OBJECTIVE

Our objective was to describe serum levels and evaluate determinants of SHBG levels in healthy children and in girls with central precocious puberty (CPP) before and during GnRH analog (GnRHa) treatment.

DESIGN

We conducted a cross-sectional study on healthy subjects and a 2-yr longitudinal study in girls with CPP.

SETTING

The study took place at a tertiary referral center for pediatric endocrinology.

PARTICIPANTS/PATIENTS

A total of 903 healthy schoolchildren served as healthy subjects, and 25 girls with precocious/early puberty participated.

INTERVENTIONS

Girls with CPP were treated with the long-acting GnRHa triptorelin.

RESULTS

SHBG levels declined with increasing age in both sexes until adulthood. In healthy children, SHBG was significantly negatively correlated with testosterone, estradiol, dehydroepiandrosterone sulfate, and body mass index (BMI) in boys (total model R(2) = 0.71) but only with dehydroepiandrosterone sulfate and BMI in girls (total model R(2) = 0.26). Body fat percentage was significantly negatively correlated with SHBG levels (P < 0.001) in both boys (R(2) = 0.18) and girls (R(2) = 0.23). Girls with CPP had significantly lower pretreatment SHBG levels compared with age-matched controls [SHBG sd score, -1.29 (-4.48; 0.01)], which declined even further during GnRHa treatment [-2.75 (-5.9; 0.53); P < 0.001]. Even after adjustment for BMI and pubertal stage, girls with CPP had lower SHBG levels (P < 0.001) compared with healthy controls.

CONCLUSIONS

SHBG levels were strongly dependent on body composition and sex steroid levels in children with normal and precocious puberty. Studies on insulin sensitivity and SHBG in puberty are needed to better understand the interaction between body composition and gonadal maturation.

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.

Gonadal hormones and gonadal function in type 2 diabetes model OLETF (Otsuka Long Evans Tokushima Fatty) rats

Gonadal functions, with special reference to blood levels of sex-related markers such as 17beta-estradiol (E2), free testosterone (free Te) and lutenizing hormone (LH), were examined in male OLETF (Otsuka Long Evans Tokushima Fatty) diabetic rats, a model of human type 2 diabetes mellitus. Male rats of the OLETF strain and male rats of the LETO strain, which act as a control of OLETF, both supplied by Otsuka Pharmaceutical Co., Ltd. (Tokushima, Japan), were periodically examined for blood levels of E2, free Te and LH at the age of 4, 5, 32, 40 and 64 weeks. The weight of the testis, the number of sperm contained within and histological findings of the testis were comparatively studied in both strains. Glucose and insulin (IRI) at fasting were examined to evaluate the homeostasis model assessment (HOMA) index. In order to investigate any sex hormone imbalance, sex hormone-binding globulin (SHBG) was measured by a dextran- charcoal assay. All of the OLETF rats became diabetic at the age of 32 weeks. There were no significant differences between OLETF and LETO rats regarding free Te, E2, LH or SHBG during the observation period from 4 to 64 weeks. Testis weight was significantly decreased in OLETF rats at 32 and 64 weeks and sperm counts at 64 weeks of age were also significantly decreased. Histologically, there was seminiferous tubule atrophy in the OLETF rats at 64 weeks of age. A significant negative correlation between testis weight and fasting blood glucose, as well as HOMA index, was observed in OLETF rats. In male diabetic OLETF rats, with a variety of hypogonadisms such as atrophy of the testis and low sperm count, the serum levels of E2, free Te, LH and SHBG were normally preserved.

Body mass index in relation to semen quality and reproductive hormones among 1,558 Danish men

OBJECTIVE

To examine the relationship between body mass index (BMI) and semen quality among young men from the general population.

DESIGN

Cross-sectional study.

SETTING

Danish young men were approached when they attended a compulsory physical examination to determine their fitness for military service.

PATIENT(S)

From 1996-1998, 1,558 (19%) young men (mean age 19 years) volunteered.

MAIN OUTCOME MEASURE(S)

Semen volume (in milliliters), sperm concentration (in million per milliliter), percentage of motile spermatozoa, percentage of spermatozoa with normal morphology, total sperm count (in million), and testis size (in milliliters). In addition, serum reproductive hormones were measured.

RESULT(S)

Serum T, sex hormone-binding globulin (SHBG), and inhibin B all decreased with increasing BMI, whereas free androgen index and E(2) increased with increasing BMI. Serum FSH was higher among slim men. After control for confounders, men with a BMI <20 kg/m(2) had a reduction in sperm concentration and total sperm count of 28.1% (95% confidence interval [CI] 8.3%-47.9%) and 36.4% (95% CI 14.6%-58.3%), respectively, and men with a BMI >25 kg/m(2) had a reduction in sperm concentration and total sperm count of 21.6% (95% CI 4.0%-39.4%) and 23.9% (95% CI 4.7%-43.2%), respectively, compared to men with BMI between 20-25 kg/m(2). Percentages of normal spermatozoa were reduced, although not significantly, among men with high or low BMI. Semen volume and percentage of motile spermatozoa were not affected by BMI.

CONCLUSION(S)

High or low BMI was associated with reduced semen quality. It remains to be seen whether the increasing occurrence of obesity in the Western world may contribute to an epidemic of poor semen quality registered in some of the same countries. If so, some cases of subfertility may be preventable.

Childhood obesity and hormonal abnormalities associated with cancer risk

There is growing evidence that overweight and obesity increase the risk of certain cancers. Studies in adults support the role of insulin-like growth factors (IGFs) and oestrogens in the pathogeneses of several cancers. We propose that hormone alterations described as risk factors for cancer in obese adults are present in prepubertal obese children. A group of obese children aged 6-9 years (n=40), and control group paired for age and sex, were used for the study. The obese children presented a significantly high level of IGF-I (P=0.0173) and insulin (P=0.0250), with a drop in sex hormone-binding globulin (SHBG) (P=0.0282). The 17 beta-oestradiol (E2)/SHBG ratio increase in obese subjects was marginally significant (P=0.0635). Grouping together all the children in quartiles for insulin and body mass index, the upper quartiles showed a rise in IGF-I and E2/SHBG. In a multivariant correlation analysis, only height (partial r=0.2464) and insulin (partial r=0.3002) were independent prediction variables for IGF-I concentration. The only variables statistically correlated with the E2/SHBG ratio were insulin (r=0.2879) and IGF-I (r=0.4140). The obese children in our study showed hormone changes described as risk factors for cancer in obese adults. These changes were significantly associated with the hyperinsulinaemia. We hypothesize that this potential risk should be taken into account given the long period of exposure involved in the presence of hormone alterations at such early ages.

Androgens and coronary artery disease

A significant and independent association between endogenous testosterone (T) levels and coronary events in men and women has not been confirmed in large prospective studies, although cross-sectional data have suggested coronary heart disease can be associated with low T in men. Hypoandrogenemia in men and hyperandrogenemia in women are associated with visceral obesity; insulin resistance; low high-density lipoprotein (HDL) cholesterol (HDL-C); and elevated triglycerides, low-density lipoprotein cholesterol, and plasminogen activator type 1. These gender differences and confounders render the precise role of endogenous T in atherosclerosis unclear. Observational studies do not support the hypothesis that dehydroepiandrosterone sulfate deficiency is a risk factor for coronary artery disease. The effects of exogenous T on cardiovascular mortality or morbidity have not been extensively investigated in prospective controlled studies; preliminary data suggest there may be short-term improvements in electrocardiographic changes in men with coronary artery disease. In the majority of animal experiments, exogenous T exerts either neutral or beneficial effects on the development of atherosclerosis. Exogenous androgens induce both apparently beneficial and deleterious effects on cardiovascular risk factors by decreasing serum levels of HDL-C, plasminogen activator type 1 (apparently deleterious), lipoprotein (a), fibrinogen, insulin, leptin, and visceral fat mass (apparently beneficial) in men as well as women. However, androgen-induced declines in circulating HDL-C should not automatically be assumed to be proatherogenic, because these declines may instead reflect accelerated reverse cholesterol transport. Supraphysiological concentrations of T stimulate vasorelaxation; but at physiological concentrations, beneficial, neutral, and detrimental effects on vascular reactivity have been observed. T exerts proatherogenic effects on macrophage function by facilitating the uptake of modified lipoproteins and an antiatherogenic effect by stimulating efflux of cellular cholesterol to HDL. In conclusion, the inconsistent data, which can only be partly explained by differences in dose and source of androgens, militate against a meaningful assessment of the net effect of T on atherosclerosis. Based on current evidence, the therapeutic use of T in men need not be restricted by concerns regarding cardiovascular side effects. Available data also do not justify the uncontrolled use of T or dehydroepiandrosterone for the prevention or treatment of coronary heart disease.

Relationship between high plasma leptin concentrations and metabolic syndrome in obese pre-pubertal children

OBJECTIVE

To evaluate the relationship between serum leptin levels and metabolic syndrome, fasting insulin level and anthropometric index in obese pre-pubertal children.

DESIGN

A cross-sectional study was carried out on obese children.

SUBJECTS

A study was made of 41 obese children (aged 6-9 y) and the same number of non-obese children (control group), matched by age and sex.

METHODS

Body mass index (BMI), waist/hip ratio (WHR) and blood pressure were determined in each child. Serum leptin, glucose, insulin, lipid profile, sex hormone binding globulin (SHBG), plasminogen activator inhibitor-1 (PAI-1), tissue-plasminogen activator (t-PA) and fibrinogen were all measured.

RESULTS

The serum leptin level was significantly higher in obese children (15.47 vs 4.73 ng/ml). In the obese group, leptin showed a positive correlation with BMI (P<0.001), insulin (P<0.001), triglycerides (P<0.05), PAI-1 (P<0.05) and t-PA (P<0.05), and correlated negatively with SHBG (P<0.01), apolipoprotein A-I (P<0.05) and high-density lipoproteins cholesterol (HDL-C) (P<0.05). Corrected for BMI and WHR, leptin (P partial=0.002) is only an independent predictive factor for basal insulin. Using multivariant regression analysis, only insulin (P partial=0.003) and BMI (P partial=0.018) were independent predictive factors for leptin.

CONCLUSION

For this age group, high leptin resistance may be another component of metabolic syndrome, and may be involved in its etiopathogenesis. The involvement of leptin in this syndrome may be indirect, modulating the insulin's action.

Relation of serum levels of sex hormone binding globulin to coronary heart disease in postmenopausal women

Hyperandrogenemia and low levels of sex hormone binding globulin (SHBG) are frequently found in women with metabolic syndrome, which is characterized by low high-density lipoprotein cholesterol, hypertriglyceridemia, obesity, and hyperinsulinemia. The specific contribution of these various factors to coronary heart disease (CHD) is controversial. The coronary angiograms of 87 consecutive postmenopausal women were evaluated using 2 semiquantitative scoring systems to estimate the extent of focal and diffuse vessel wall alterations. Fasting sera were analyzed for levels of glucose, lipids, insulin, leptin, dehydroepiandrosterone sulfate, testosterone, and SHBG. Obesity was assessed by measuring body mass index, waist-to-hip ratio, skinfold thicknesses, and body impedance. After adjusting for age, there were significant differences in 55 women with CHD compared with 32 women without CHD: higher levels of low-density lipoprotein cholesterol (159 +/- 51 vs 132 +/- 39 mg/dl), apolipoprotein B (121 +/- 33 vs 102 +/- 29 mg/dl), triglycerides (115 vs 91 mg/dl), and basal insulin (7.5 vs 4.6 mU/L), as well as lower levels of high-density lipoprotein cholesterol (59.9 +/- 18.0 vs 69.0 +/- 17.1 mg/dl), SHBG (44.6 vs 68.1 nmol/L) and the quantitative insulin sensitivity check index (0.66 +/- 0.41 vs 0.93 +/- 0.73). Multivariate analysis by logistic regression identified age (odds ratio [OR] 1.22, 95% confidence intervals [CI] 1.09 to 1.37), smoking (OR 11.46, 95% CI 2.56 to 51.39), SHBG (OR 0.98, 95% CI 0.96 to 0.99), and apolipoprotein B (OR 1.02, 95% CI 1.01 to 1.04) as independently associated with the presence of CHD. Thus, low plasma levels of SHBG are associated with CHD in women independently of insulin, obesity markers, and dyslipidemia.