Hyperinsulinemia and sex hormones in healthy premenopausal women: relative contribution of obesity, obesity type, and duration of obesity

Association between Body Mass Index and Diabetes Mellitus Are Mediated through Endogenous Serum Sex Hormones among Menopause Transition Women: A Longitudinal Cohort Study

OBJECTIVE

To explore whether and to what extent endogenous sex hormones mediate the association between overweight and diabetes risk in menopausal transition women.

METHODS

Premenopausal women were from the Study of Women's Health Across the Nation, with measurements of serum sex hormone including sex hormone binding globulin (SHBG), testosterone (T), estradiol (E2), follicle-stimulating hormone (FSH), and dehydroepiandrosterone sulfate (DHAS) in first postmenopausal follow-up. At the last postmenopausal follow-up, hyperglycemia status was confirmed. The partial least squares (PLS) regression method was used to extract hormonal signals associated with body mass index (BMI). Hyperglycemia was defined as individuals with prediabetes or diabetes; overweight was defined as BMI ≥ 25 kg/m². Causal mediation analysis was used to examine the mediation effect on the association between perimenopause overweight and post-menopause hyperglycemia through PLS score and individual sex hormones.

RESULTS

The longitudinal study included 1438 normal glucose women with a baseline mean age (SD) of 46.5 (2.6) years and a mean follow-up period of 9.9 years. During the follow-up period, 145 (10.1) cases of hyperglycemia occurred. Compared with normal-weight participants, overweight women were associated with a higher hyperglycemia risk during the transition period (OR = 4.06, 95% CI: 2.52 to 6.80). Overweight women had higher T, E2, and lower SHBG, FSH, and DAHS concentrations (β = 0.26, 0.38, -0.52, -0.52, and -0.13, p < 0.05 for all). After adjusting for overweight and covariates, lower SHBG and FSH levels were associated with higher hyperglycemia risk (OR = 0.70 and 0.69, all p < 0.05). As a linear combination of sex hormones, the PLS score was positively associated with T, E2, and negatively with SHBG, FSH, and DHAS. PLS score interpreted 36.50% (p < 0.001) of the overweight-hyperglycemia association. Considering single-sex hormones, the mediation proportion of SHBG and FSH were 21.38% (p < 0.001) and 24.08% (p < 0.001).

CONCLUSIONS

Sex hormones mediated the association of overweight and diabetes risk in menopause transition women. SHBG and FSH have the dominant mediation effect.

Obesity, Body Composition, and Sex Hormones: Implications for Cardiovascular Risk

Cardiovascular disease (CVD) continues to be the leading cause of death in adults, highlighting the need to develop novel strategies to mitigate cardiovascular risk. The advancing obesity epidemic is now threatening the gains in CVD risk reduction brought about by contemporary pharmaceutical and surgical interventions. There are sex differences in the development and outcomes of CVD; premenopausal women have significantly lower CVD risk than men of the same age, but women lose this advantage as they transition to menopause, an observation suggesting potential role of sex hormones in determining CVD risk. Clear differences in obesity and regional fat distribution among men and women also exist. While men have relatively high fat in the abdominal area, women tend to distribute a larger proportion of their fat in the lower body. Considering that regional body fat distribution is an important CVD risk factor, differences in how men and women store their body fat may partly contribute to sex-based alterations in CVD risk as well. This article presents findings related to the role of obesity and sex hormones in determining CVD risk. Evidence for the role of sex hormones in determining body composition in men and women is also presented. Lastly, the clinical potential for using sex hormones to alter body composition and reduce CVD risk is outlined. © 2022 American Physiological Society. Compr Physiol 12:1-45, 2022.

Testosterone in Female Depression: A Meta-Analysis and Mendelian Randomization Study

Testosterone's role in female depression is not well understood, with studies reporting conflicting results. Here, we use meta-analytical and Mendelian randomization techniques to determine whether serum testosterone levels differ between depressed and healthy women and whether such a relationship is casual. Our meta-analysis shows a significant association between absolute serum testosterone levels and female depression, which remains true for the premenopausal group while achieving borderline significance in the postmenopausal group. The results from our Mendelian randomization analysis failed to show any causal relationship between testosterone and depression. Our results show that women with depression do indeed display significantly different serum levels of testosterone. However, the directions of the effect of this relationship are conflicting and may be due to menopausal status. Since our Mendelian randomization analysis was insignificant, the difference in testosterone levels between healthy and depressed women is most likely a manifestation of the disease itself. Further studies could be carried out to leverage this newfound insight into better diagnostic capabilities culminating in early intervention in female depression.

Do the Low WHRs and BMIs Judged Most Attractive Indicate Higher Fertility?

We examine the widely accepted view that very low waist-hip ratios and low body mass indices (BMIs) in women in well-nourished populations are judged attractive by men because these features reliably indicate superior fertility. In both subsistence and well-nourished populations, relevant studies of fertility do not support this view. Rather studies indicate lower fertility in women with anthropometric values associated with high attractiveness. Moreover, low maternal BMI predisposes to conditions that compromise infant survival. Consistent with these findings from the literature, new data from a large U.S. sample of women past reproductive age show that women with lower BMIs in the late teens had fewer live births, controlling for education, marital history, and race. They also had later menarche and earlier menopause compared with women with higher youth BMIs. In addition, data from the 2013 U.S. natality database show that mothers with lower prepregnancy BMIs have an increased risk of producing both low-birth-weight and preterm infants controlling for other relevant variables-conditions that would have adversely affected fitness over almost all of human evolution. Thus, a review of the relevant literature and three new tests fail to support the view that highly attractive women are more fertile.

PPAR-γ receptor agonists-a review of their role in diabetic management in Trinidad and Tobago

The PPAR-γ receptor agonists, as a relatively new and perhaps still not very widely used class of antidiabetic agent in the Caribbean and particularly the Trinidadian context, possess pharmacologic properties that certainly have been shown to have impact on many of the inflammatory, metabolic, biochemical and structural macrovascular aberrations that occur in the type 2 diabetic. Activation of PPAR(gamma) nuclear receptors regulates the transcription of insulin-responsive genes involved in the control of glucose production, transport, and utilization. PPAR(gamma)-responsive genes also participate in the regulation of fatty acid metabolism, an important contributory pathogenic factor in this subset of patients. The unique mode of action of this class of therapeutic agent addresses a range of anomalies occurring at the cellular and sub-cellular level that are injurious to the diabetic. My aim in addressing the issue of the potential impact of PPAR-γ receptor agonists on cardiovascular disease (CVD) morbidity and mortality in the diabetic, is first, to seek to enhance both an awareness of, and greater familiarity among our own physicians, with this class of drug, and secondly, to effect a timely review of the recent literature as it relates to the tremendous possibilities for the potential clinical gains that might accrue from their use, in so far as this may serve to ameliorate the ravages of the CVD disease that all too tragically attends the type 2 diabetic, and more specifically those with the insulin resistance syndrome. (Mol Cell Biochem 263: 189-210, 2004).

Circulating 5α-dihydrotestosterone, abdominal obesity and adipocyte characteristics in women

Abstract Background: The association between circulating androgen levels and fat distribution in women has been widely inconsistent among existing studies.

OBJECTIVE

We sought to investigate the relation between plasma adrenal and gonadal androgen levels and body fat distribution, as well as abdominal adipocyte characteristics.

METHODS

Paired omental and subcutaneous adipose tissue samples were surgically obtained from 60 women (age, 47±5 years; body mass index, 26±5 kg/m2) undergoing gynecological surgery. Body composition and fat distribution were measured by dual-energy X-ray absorptiometry and computed tomography, respectively. Adipocyte diameter, basal lipolysis, and heparin-releasable lipoprotein lipase activity were measured. Steroids were quantified using high-performance gas chromatography and mass spectrometry.

RESULTS

Significant negative associations were found between plasma dihydrotestosterone (DHT) levels and total adiposity (body mass index, r=-0.35, p<0.05; fat mass, r=-0.31, p<0.05) as well as computed tomography assessments of abdominal adiposity (r=-0.30, p<0.05 and r=-0.44, p<0.005 for subcutaneous and visceral adipose tissue area, respectively). The association between DHT levels and visceral adipose tissue area was independent of total body fat mass. A significant negative association was also observed between plasma DHT and omental adipocyte diameter (r=-0.27, p<0.05). When expressed as the omental/subcutaneous ratio, heparin-releasable lipoprotein lipase activity was negatively and significantly related to plasma DHT, androstenedione, and dehydroepiandrosterone (DHEA) levels.

CONCLUSION

Abdominally obese women with large, metabolically active omental adipocytes appear to be characterized by reduced endogenous levels of DHT. The assumption that high androgen levels are associated with an android body fat distribution pattern in women should be critically re-examined.

Hyperandrogenemia in polycystic ovary syndrome: exploration of the role of free testosterone and androstenedione in metabolic phenotype

Objective

To evaluate the association between androstenedione, testosterone, and free testosterone and metabolic disturbances in polycystic ovary syndrome.

Methods

We analyzed the association between androstenedione, testosterone, and free testosterone and metabolic parameters in a cross-sectional study including 706 polycystic ovary syndrome and 140 BMI-matched healthy women. Polycystic ovary syndrome women were categorized into 4 groups: normal androstenedione and normal free testosterone (NA/NFT), elevated androstenedione and normal free testosterone (HA/NFT), normal androstenedione and elevated free testosterone (NA/HFT), elevated androstenedione and free testosterone (HA/HFT).

Results

Polycystic ovary syndrome women with elevated free testosterone levels (HA/HFT and NA/HFT) have an adverse metabolic profile including 2 h glucose, HbA1c, fasting and 2 h insulin, area under the insulin response curve, insulin resistance, insulin sensitivity index (Matsuda), triglycerides, total and high density lipoprotein cholesterol levels compared to NA/NFT (p<0.05 for all age- and BMI-adjusted analyses). In binary logistic regression analysis adjusted for age and BMI, odds ratio for insulin resistance was 2.78 (1.34–5.75, p = 0.006) for polycystic ovary syndrome women with HA/HFT compared to NA/NFT. We found no significantly increased risk of metabolic disorders in polycystic ovary syndrome women with HA/NFT. In multiple linear regression analyses (age- and BMI-adjusted), we found a significant negative association between androstenedione/free testosterone-ratio and area under the insulin response curve, insulin resistance, and total cholesterol/high density lipoprotein cholesterol-ratio and a positive association with Matsuda-index, and high density lipoprotein cholesterol (p<0.05 for all).

Conclusions

Polycystic ovary syndrome women with elevated free testosterone levels but not with isolated androstenedione elevation have an adverse metabolic phenotype. Further, a higher androstenedione/free testosterone-ratio was independently associated with a beneficial metabolic profile.

Intakes of anthocyanins and flavones are associated with biomarkers of insulin resistance and inflammation in women

Although laboratory data suggest that several flavonoid subclasses are involved in glucose metabolism, limited clinical and epidemiologic data are available. The current study examined associations between habitual intake of flavonoid subclasses, insulin resistance, and related inflammatory biomarkers. In a cross-sectional study of 1997 females aged 18-76 y, intakes of total flavonoids and their subclasses (flavanones, anthocyanins, flavan-3-ols, polymeric flavonoids, flavonols, flavones) were calculated from food frequency questionnaires using an extended USDA database. Fasting serum glucose, insulin, high-sensitivity C-reactive protein (hs-CRP; n = 1432), plasminogen activator inhibitor-1 (n = 843), and adiponectin (n = 1452) concentrations were measured. In multivariable analyses, higher anthocyanin and flavone intake were associated with significantly lower peripheral insulin resistance [homeostasis model assessment of insulin resistance; quintile 5 (Q5) to Q1 = -0.1, P-trend = 0.04 for anthocyanins and flavones] as a result of a decrease in insulin concentrations (Q5-Q1 = -0.7 μU/mL, P-trend = 0.02 anthocyanins; Q5-Q1 = -0.5 μU/mL, P-trend = 0.02 flavones). Higher anthocyanin intake was also associated with lower hs-CRP concentrations (Q5-Q1 = -0.3 mg/L, P-trend = 0.04), whereas those in the highest quintile of flavone intake had improved adiponectin concentrations (Q5-Q1 = 0.7 μg/L, P-trend = 0.01). Anthocyanin-rich foods were also associated with lower insulin and inflammation levels. No significant associations were observed for total or other flavonoid subclasses. Higher intakes of both anthocyanins and flavones were associated with improvements in insulin resistance and hs-CRP. These associations were found with intakes readily achieved in the diet. The observed reduction in insulin concentrations was similar to that reported previously for other lifestyle factors. Dose-response trials are needed to ascertain optimal intakes for the potential reduction of type 2 diabetes risk.

Associations between body size and serum estradiol and sex hormone-binding globulin levels in premenopausal African American women

CONTEXT

African American (AA) women have the highest rates of premenopausal breast cancer; however, it is unclear whether body size contributes to the hormonal patterns potentially associated with increased breast cancer risk in these women.

OBJECTIVE

To characterize the association between body size and serum levels of estradiol and sex hormone-binding globulin (SHBG) levels in a sample of premenopausal AA women.

DESIGN

A total of 164 premenopausal AA women who were not pregnant or breastfeeding were recruited for this study. Serum samples were collected during the early follicular phase, and trained staff collected body size measurements. Multiple linear regression models were performed to assess potential associations.

MAIN OUTCOME MEASURES

Serum estradiol and SHBG levels.

RESULTS

Many (81%) of the women enrolled were overweight or obese. Both waist-to-hip ratio (WHR) (β = 2.68, P = .008) and waist circumference (WC) (β = 2.02, P = .046) were positively associated with higher levels of estradiol. All measures of body was significantly and inversely associated with SHBG levels (all P < .05).

CONCLUSIONS

Premenopausal AA women with higher WHR or larger WC may have higher levels of estradiol and lower levels of SHBG. Thus, WHR or WC may be better indicators for assessing hormonal patterns implicated in breast cancer pathogenesis in these women.

Effects of aerobic exercise training on serum sex hormone binding globulin, body fat index, and metabolic syndrome factors in obese postmenopausal women

BACKGROUND

The percentage of obese postmenopausal women with metabolic syndrome is rising, and physical factors associated with the metabolic syndrome prevalence or incidence are also rising, including high body mass index (BMI), visceral fat area (VFA), low plasma sex hormone-binding globulin (SHBG) levels, and low cardiorespiratory fitness. Therefore, we investigated the influence of aerobic exercise on SHBG, body fat index (BFI), and metabolic syndrome factors in obese postmenopausal Korean women.

METHODS

Thirty healthy postmenopausal, women aged 53.46 ± 2.4 years and with over 32% body fat, were randomly assigned to an aerobic exercise group (EX; n=15) or to a "nonexercise" control (Con; n=15) group. The primary outcome measurements were serum SHBG, lipid profiles, insulin levels, and metabolic syndrome factors. Secondary outcome measurements were body composition, VFA, blood pressure (BP), and homeostasis model assessment of insulin resistance (HOMA-IR).

RESULTS

Posttraining body weight and BFI (P<0.05), total cholesterol, glucose, and insulin levels (P<0.01), BP, and HOMA-IR (P<0.001) decreased, whereas SHBG (P<0.001) and metabolic syndrome factors (P<0.01) improved in the exercise group but not in the control group. SHBG levels also showed a significant positive correlation with high-density lipoprotein cholesterol (HDL-C) and significant negative correlations withglucose, diastolic blood pressure, fat mass, BMI, and percent body fat (P<0.05).

CONCLUSIONS

Our findings indicate that aerobic exercise improves body composition, SHBG, insulin levels, and metabolic syndrome factors. These findings suggest that in obesepostmenopausal Korean women, 16 weeks of aerobic exercise is effective for preventing the metabolic syndrome caused by obesity.

Associations of body size and reproductive factors with circulating levels of sex hormones and prolactin in premenopausal Japanese women

OBJECTIVE

Body size and reproductive factors are important risk factors of breast cancer. The aim of the present study was to examine the associations of these factors with blood concentrations of sex hormones and prolactin in premenopausal Japanese women.

METHODS

We measured the plasma concentrations of estradiol, estrone, testosterone, dehydroepiandrosterone sulfate (DHEAS), sex hormone-binding globulin (SHBG), follicle-stimulating hormone, luteinizing hormone, and prolactin among 436 women who had regular menstrual cycles less than 40 days long. Information on menstrual and reproductive factors including history of breastfeeding was obtained using a self-administered questionnaire. Height and weight were measured.

RESULTS

After controlling for age and the phase of the menstrual cycle, the body mass index (BMI) was significantly inversely associated with total estradiol, estrone and SHBG and significantly positively associated with total and free testosterone and DHEAS. Nulliparous women had significantly higher levels of total and free testosterone, DHEAS, and prolactin than parous women. Duration of breastfeeding for the first child was significantly inversely associated with free testosterone and prolactin levels.

CONCLUSIONS

The data suggest that an increased risk of premenopausal breast cancer associated with low BMI is partially mediated by an increased total estradiol. Androgens and prolactin may explain the breast cancer protection provided by giving birth and breastfeeding.

Racial differences in the association between sex hormone-binding globulin and adiposity in premenopausal women: the BioCycle study

OBJECTIVE

To assess the associations between measures of adiposity and sex hormone- binding globulin (SHBG) and to evaluate whether such associations differ by race.

RESEARCH DESIGN AND METHODS

Adiposity was measured by anthropometry and dual-energy X-ray absorptiometry among women (146 white, 50 black, and 25 Asian) aged 18-44 years in the BioCycle study. SHBG was repeatedly measured over one to two menstrual cycles. The ratio of trunkal to leg fat (T/L) was used to assess upper to lower body adiposity.

RESULTS

Among whites, all adiposity measures were significantly and inversely associated with SHBG. Among blacks, BMI (β = -0.032), waist circumference (β = -0.016), and T/L (β = -0.033) were significantly associated with SHBG, whereas total and trunkal fat were not (P interaction with race <0.04). Among Asians, measures of central and upper body fat were significantly associated with SHBG (e.g., T/L, β = -0.84) but not BMI.

CONCLUSIONS

Associations between SHBG and adiposity differ by race among premenopausal women.

Endocrinology of obesity

Obesity is a growing health concern in humans and companion animals. Obesity is highly associated with various endocrine abnormalities that are characterized by hormonal imbalance and/or resistance. Weight reduction generally normalizes these endocrine alterations, implicating obesity as a direct cause. Most data in this area have been derived from obese humans, with little data pertaining to hormonal changes in obese dogs and cats. Because the literature contains inconsistent results and because considerable hormone-hormone interactions occur, we have a limited understanding of the obesity-induced changes on the endocrine system in dogs and cats.

Effects of androgens on adipocyte differentiation and adipose tissue explant metabolism in men and women

OBJECTIVE

To examine the effects of aromatizable or nonaromatizable androgens on abdominal subcutaneous (SC) and omental (OM) adipose tissue lipid metabolism and adipogenesis in men and women.

DESIGN AND SUBJECTS

Primary organ and preadipocyte cultures were established from surgical samples obtained in men (n = 22) and women undergoing biliopancreatic diversions (n = 12) or gynaecological surgeries (n = 8). Cultures were treated with testosterone, dihydrotestosterone (DHT) and methyltrienolone (R1881).

MEASUREMENTS

Heparin-releasable lipoprotein lipase (HR-LPL) activity, glycerol release, adiponectin secretion, glycerol-3-phosphate dehydrogenase activity and lipid accumulation were measured.

RESULTS

In organ cultures from men, DHT had a statistically significant inhibitory effect on HR-LPL activity in the OM compartment. Testosterone significantly inhibited HR-LPL activity in SC and OM cultures. In women, high DHT concentrations tended to inhibit HR-LPL activity in OM cultures. Minor androgenic effects were observed for basal and isoproterenol-stimulated lipolysis as well as adiponectin release in men. On the other hand, adipocyte differentiation was significantly and dose-dependently inhibited by DHT, testosterone and R1881 in SC and OM cultures from both sexes. These effects did not differ according to adipose tissue depot but appeared to be more pronounced in women than in men.

CONCLUSIONS

Androgens slightly decreased HR-LPL activity in adipose tissue organ cultures, but markedly inhibited adipogenesis in SC and OM primary preadipocyte cultures in both sexes. Androgenic effects on adipose tissue in men vs. women may not differ in terms of direction but in the magnitude of their negative impact on adipogenesis and lipid synthesis.

Androgen metabolism in adipose tissue: recent advances

Androgens modulate adipocyte function and affect the size of adipose tissue compartments in humans. Aldo-keto reductase 1C (AKR1C) enzymes, especially AKR1C2 and AKR1C3, through local synthesis and inactivation of androgens, may be involved in the fine regulation of androgen availability in adipose tissue. This review article summarizes recent findings on androgen metabolism in adipose tissue. Primary culture models and whole tissue specimens of human adipose tissue obtained from the abdominal subcutaneous and intra-abdominal (omental) fat compartments were used in our studies. The non-aromatizable androgen dihydrotestosterone (DHT) inhibits adipocyte differentiation in subcutaneous and omental adipocytes in humans. This inhibitory effect is partially reversed by anti-androgens. Activity and mRNA expression of AKR1C1, 2 and 3 were detected in SC and OM adipose tissue, in men and women, with higher levels in the SC depot than the omental depot of both sexes. The abundance of AKR1C enzyme mRNAs was particularly elevated compared to other steroid-converting enzymes. Significant positive associations were observed between AKR1C enzyme mRNA levels or DHT inactivation rates and visceral fat accumulation as well as OM adipocyte size in women and in men, at least in the normal weight to moderately obese range. Mature adipocytes had significantly higher DHT inactivation rates compared to preadipocytes. Accordingly, adipocyte differentiation significantly increased AKR1C enzyme expression and DHT inactivation rates. Treatment of preadipocytes with dexamethasone alone led to significant increases in the formation of 5alpha-androstan-3alpha,17beta-diol. This stimulation was completely abolished by RU486, suggesting that androgen inactivation is stimulated by a glucocorticoid receptor-dependent mechanism. In conclusion, higher AKR1C activity and expression in mature adipocytes may explain the associations between these enzymes and obesity. We speculate that glucocorticoid-induced androgen inactivation could locally decrease the exposure of adipose cells to active androgens and partially remove their inhibitory effect on adipogenesis. We hypothesize that body fat distribution patterns likely emerge from the local adipose tissue balance between active androgens and glucocorticoids in each fat compartment.

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.

Research methodology: endocrinologic measurements in exercise science and sports medicine

OBJECTIVE

To provide background information on methodologic factors that influence and add variance to endocrine outcome measurements. Our intent is to aid and improve the quality of exercise science and sports medicine research endeavors of investigators inexperienced in endocrinology.

BACKGROUND

Numerous methodologic factors influence human endocrine (hormonal) measurements and, consequently, can dramatically compromise the accuracy and validity of exercise and sports medicine research. These factors can be categorized into those that are biologic and those that are procedural-analytic in nature.

RECOMMENDATIONS

Researchers should design their studies to monitor, control, and adjust for the biologic and procedural-analytic factors discussed within this paper. By doing so, they will find less variance in their hormonal outcomes and thereby will increase the validity of their physiologic data. These actions can assist the researcher in the interpretation and understanding of endocrine data and, in turn, make their research more scientifically sound.

Body fat, energy balance and estradiol levels: a study based on hormonal profiles from complete menstrual cycles

BACKGROUND

Female fecundity is regulated by nutritional status. Although widely cited, this hypothesis is not strongly supported by empirical data from non-obese, healthy women of reproductive age.

METHODS

Healthy, reproductive aged women (n = 141) from Southern Poland collected daily morning saliva samples for one complete menstrual cycle. Levels of 17-beta-estradiol were analyzed by radioimmunoassay. Anthropometric measurements, including body fat percentage, were taken randomly with respect to phase of the menstrual cycle. Energy balance was specified based on changes in body fat percentage from the beginning to the end of the observation period.

RESULTS

Women with very low and high body fat had significantly lower levels of E2 compared with women with low and average body fat. In women of very low to average body fat, a 10% increase in body fat was associated with a 5-7 pmol/l increase in estradiol levels. The association between fat percentage and E2 was even stronger in women with positive energy balance, who also showed significant differences between body fat groups in estradiol profiles across whole the menstrual cycle. No such relationship was found in women with negative energy balance.

CONCLUSIONS

In healthy women, we found a non-linear association between body fat and estradiol levels. Both very low and high body fat was associated with decreased estradiol levels. The relationship between estradiol and body fat was strongly influenced by women's energy balance.

Changes over 14 years in androgenicity and body mass index in a biracial cohort of reproductive-age women

BACKGROUND

Body mass index (BMI) is directly related to testosterone (total T and free T) and inversely to SHBG cross-sectionally, but little is known about how changes in body fat and androgen markers affect each other over time.

METHODS

Participants included 969 White and Black women from the Coronary Artery Risk Development in Young Adults (CARDIA) cohort, who were ages 18-30 at entry into the study and were pre- or perimenopausal 16 yr later at the time of the CARDIA Women's Study (CWS). Total T and SHBG were assayed from specimens drawn at the CWS examination and stored serum from the yr 2 and 10 CARDIA exams. Free T was calculated based on total T and SHBG. BMI and waist circumference were measured at yr 2, 10, and 16.

RESULTS

Despite clinically significant increases in BMI and waist circumference, total T and free T tended to decline, whereas SHBG remained relatively constant. BMI and waist circumference were directly correlated with free T and inversely correlated with SHBG in cross-sectional analyses. In longitudinal, multivariable analyses, an annualized increase in BMI was inversely related to a concurrent annualized decrease in SHBG (beta = -0.79 ng/dl, and se = 0.22 in Blacks; beta = -1.07 ng/dl; and se = 0.31 in Whites). However, early increases in BMI were not related to later decreases in SHBG.

CONCLUSION

Increases in adiposity are closely tied to decreases in SHBG, but changes in BMI and SHBG may occur concurrently rather than sequentially.

Prognostic value of body mass index in locally advanced breast cancer

PURPOSE

The purpose of this retrospective study was to determine the association and prognostic value of body mass index (BMI) at the time of initial diagnosis in patients with locally advanced breast cancer (LABC). The analysis includes the subsets of inflammatory (IBC) and noninflammatory (non-IBC LABC) breast cancer.

EXPERIMENTAL DESIGN

We identified 602 patients who had LABC treated on prospective clinical trials. BMI was divided into three groups: (a) < or =24.9 (normal/underweight), (b) 25.0 to 29.9 (overweight), and (c) > or =30 (obese). Kaplan-Meier product limit method was used to estimate survival outcomes. Cox proportional hazards were used to determine associations between survival and BMI and to test for an interaction between BMI and breast cancer type.

RESULTS

Eighty-two percent had non-IBC LABC and 18% had IBC. Obese patients tended to have a higher incidence of IBC compared with overweight and normal/underweight groups (P = 0.01). Median follow up was 6 years for all patients. Median overall survival (OS) and recurrence-free survival (RFS) were 8.8 and 5.9 years, respectively. Patients with LABC who were obese or overweight had a significantly worse OS and RFS (P = 0.001) and a higher incidence of visceral recurrence compared with normal/underweight patients. In a multivariable model, BMI remained significantly associated with both OS and RFS for the entire cohort. The interactions between BMI and LABC subsets and between BMI and menopausal status were not statistically significant.

CONCLUSION

Patients with LABC and high BMI have a worse prognosis. Evaluation of the biological factors associated with this observation can provide tools for additional therapeutic interventions.

Birthweight and body size throughout life in relation to sex hormones and prolactin concentrations in premenopausal women

The association of birthweight and body size throughout life with premenopausal breast cancer risk may be due, in part, to relationships with sex hormones. Therefore, we assessed whether birthweight, body shape at ages 5 and 10, body mass index (BMI) at age 18 and adulthood, adult waist circumference and waist-to-hip ratio (WHR), and attained height were associated with the plasma concentrations of estrogens, androgens, progesterone, prolactin, and sex hormone-binding globulin (SHBG) in 592 premenopausal women, ages 33 to 52 years old, from the Nurses' Health Study II. About 85% of women provided blood samples during follicular and luteal menstrual phases; other women had a single untimed sample. We observed few associations between sex hormone levels and birthweight or body shape in childhood. However, adult BMI was inversely associated with SHBG (P trend < 0.001) and positively associated with free testosterone (P trend < 0.001) concentrations. Adult BMI was not associated with follicular or luteal free estradiol levels (P trend >or= 0.15) because it was inversely associated with total estradiol levels (P trend < 0.001 for follicular and luteal estradiol levels). Testosterone, androstenedione, and progesterone were inversely associated with BMI. Comparing women with a BMI of >or=30 versus <20 kg/m2, levels were higher by 53% for free testosterone and lower by 51% for SHBG, 39% for follicular estradiol, 20% for luteal estradiol, 14% for androstenedione, 13% for testosterone, and 20% for progesterone. We observed no clear associations between BMI at age 18, waist circumference, WHR, or height, and sex hormone concentrations. Our results suggest that effects on premenopausal sex hormone levels may be one mechanism through which adult adiposity, but not birthweight or childhood body size, affects premenopausal breast cancer risk.

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.

Steroidogenic alterations and adrenal androgen excess in PCOS

BACKGROUND

This cross-sectional study was undertaken to improve our understanding of the steroidogenic alterations leading to adrenal hyperandrogenism in polycystic ovarian syndrome (PCOS).

METHODS

Two-hundred and thirty-four women with clinical and biochemical features suggestive of PCOS underwent metabolic and hormonal evaluation. We used the androstenedione/DHEAS ratio as a surrogate for the level of ovarian 3betaHSD activity. We then selected the 90th percentile for the ratio in those with elevated DHEAS (>9 micromol/l) as the cut-off level beyond which excess DHEAS production will be minimized by excess ovarian 3betaHSD activity. This cut-off level was at a ratio of 1.5 and all PCOS women were then divided into two groups, the higher (>1.5) being the group with excess ovarian 3betaHSD activity. We hypothesized that women with a high ratio would be unlikely to have DHEAS excess due to the rapid conversion of DHEA to androstenedione. Those with a low ratio (concordant ovarian and adrenal steroidogenesis) could then either have high DHEAS or normal DHEAS, depending on whether CYP17 activity was higher or lower respectively.

RESULTS

Insulin resistance was found to be associated with decreased CYP17 activity while irregular cycles and neuroendocrine dysfunction were determined to be associated with higher ovarian 3betaHSD activity.

CONCLUSION

Adrenal androgen excess in PCOS seems to be related to insulin sensitivity as well as decreased activity of 3betaHSD, the latter being preferentially present in those women with regular cycles or without neuroendocrine dysfunction.

The association between magnesium intake and fasting insulin concentration in healthy middle-aged women

OBJECTIVE

We assessed the association between magnesium intake and fasting insulin levels in a large cohort of women.

METHODS

Female nurses free of diabetes, cardiovascular diseases and cancer from the Nurses Health Study provided blood samples between 1989-1990. We selected a sub-sample of 219 women for this analysis. Magnesium intake was assessed by a food frequency questionnaire in 1990 and categorized into quartiles. Cross-sectional geometric means of fasting insulin concentrations by quartiles of magnesium intake were obtained with Generalized Linear Model and adjusted for several risk factors and lifestyle characteristics.

RESULTS

After adjustment for age, body mass index (BMI), total energy, physical activity, hours per week spent sitting outside work, alcohol intake, smoking, and family history of diabetes, magnesium intake was inversely associated with fasting insulin concentration. The multivariate adjusted geometric mean for women in the lowest quartile of magnesium intake was 11.0 microU/mL and 9.3 microU/mL among those in the highest quartile of magnesium intake (p for trend = 0.04). The inverse association remained when we considered magnesium from only food sources.

CONCLUSION

Higher magnesium intake is associated with lower fasting insulin concentrations among women without diabetes. Because lower fasting insulin concentrations generally reflect greater insulin sensitivity, these findings provide a mechanism through which higher dietary magnesium intake may reduce the risk of developing type 2 diabetes mellitus.

Interactions of metabolic hormones, adipose tissue and exercise

Physiological and psychological systems work together to determine energy intake and output, and thus maintain adipose tissue. In addition, adipose tissue secretes leptin and cytokines, which induces satiety and has been linked to catecholamines, cortisol, insulin, human growth hormone, thyroid hormones, gonadotropin and lipolysis. Thus, adipose tissue is acted upon by a number of physiological stimuli, including hormones, and simultaneously, is an active component in the regulation of its own lipid content. All of the hormones mentioned above are associated with each other and respond to exercise and exercise training. Thus, exercise is one of the major links between the hormonal modulators of energy intake and output. It appears that the sympathetic nervous system and the catecholamines are key components facilitating the lipolytic activity during exercise. These two neuroendocrine factors directly affect adipose metabolism and metabolic hormones that influence adipose metabolism. Acute low- and moderate-intensity exercise causes hormonal changes that facilitate lipolytic activity. Exercise training reduces these hormonal responses, but the sensitivity to these hormones increases so that lipolysis may be facilitated. Large amounts of adipose tissue blunt the metabolic hormonal responses to exercise, but the sensitivity of these hormones is increased; thus maintaining normal lipolytic activity. Although the physiological role of the endocrine system during exercise and training is significant, other training effects may have as great, or greater influence on lipolytic activity in adipose tissue.

Acanthosis nigricans: clinical predictor of abnormal glucose tolerance in Asian women with polycystic ovary syndrome

The aim of this retrospective study was to assess whether acanthosis nigricans is a predictive factor for abnormal glucose tolerance (AGT) in Asian women with polycystic ovary syndrome (PCOS). Data from the record forms and electronic form of 121 PCOS women who consecutively attended the Reproductive Endocrinology and Infertility Unit were reviewed. In accordance with the unit's guidelines, all women received a physical examination, had anthropometric measurements taken and underwent as a 75-g oral glucose tolerance test after diagnosis. Their age, body mass index (BMI) and waist/hip ratio (WHR) was 29.1+/-6.1 years, 27.4+/-6.8 kg/m2 and 0.84+/-0.6 (mean+/-standard deviation), respectively. The prevalence of AGT was 42.9%, with 1.6% having impaired fasting glucose, 32.3% having impaired glucose tolerance and 9.1% having type 2 diabetes mellitus. The PCOS women with acanthosis nigricans had significantly higher BMI, WHR, fasting glucose, 2-h post-load glucose, fasting insulin, 2-h post-load insulin and prevalence of AGT compared with those without acanthosis nigricans. By logistic regression analysis, acanthosis nigricans and WHR were independent predictors for AGT, with an odds ratio (95% confidence interval) of 2.7 (1.1-7.1) and 10.1 (1.8-20.7), respectively. In conclusion, acanthosis nigricans was demonstrated as a predictive factor for AGT in Asian women with PCOS.

Obesity and outcomes in premenopausal and postmenopausal breast cancer

PURPOSE

Obesity is associated with adverse outcomes in postmenopausal women with breast cancer. In premenopausal women, the association is less clear.

METHODS

A population-based sample of 1,360 Australian women with breast cancer before the age of 60 years, 47% diagnosed before age 40, and 74% premenopausal, was studied prospectively for a median of 5 years (range, 0.2-10.8 years). Obesity was defined as a body mass index of > or =30 kg/m2. The hazard ratio (HR) for adverse clinical outcome associated with obesity was estimated using Cox proportional hazard survival models.

RESULTS

Obesity increased with age (P < 0.001) and was associated with increased breast cancer recurrence (P = 0.02) and death (P = 0.06), larger tumors (P = 0.002), and more involved axillary nodes (P = 0.003) but not with hormone receptor status (P > or = 0.6) or with first cycle adjuvant chemotherapy dose reductions (P = 0.1). Adjusting for number of axillary nodes, age at diagnosis, tumor size, grade, and hormone receptor status, obese women of all ages were more likely than nonobese women to have disease recurrence [HR, 1.57; 95% confidence interval (95% CI), 1.11-2.22; P = 0.02] and to die from any cause during follow-up (HR, 1.56; 95% CI, 1.01-2.40; P = 0.05). In premenopausal women, the adjusted HRs were 1.50 (95% CI, 1.00-2.26; P = 0.06) and 1.71 (95% CI, 1.05-2.77; P = 0.04), respectively.

CONCLUSIONS

Obesity is independently associated with poorer outcomes in premenopausal women, as it is in postmenopausal women, and this is not entirely explained by differences in tumor size or nodal status. Given the high and increasing prevalence of obesity in western countries, more research on improving the treatment of obese breast cancer patients is warranted.

Association between the T27C polymorphism in the cytochrome P450 c17alpha (CYP17) gene and risk factors for breast cancer

Mammographic density is associated with increased breast cancer risk and is influenced by sex hormones. A T27C polymorphism (alleles A1 and A2, respectively) in the 5' promoter region of CYP17 may be associated with elevated sex hormone levels. In a cross-sectional study of 181 pre- and 173 postmenopausal women, we examined the relationship of this polymorphism with mammographic density and other risk factors for breast cancer. Subjects were recruited across five categories of density. Risk factor and dietary information, anthropometric measures, and blood samples were obtained. Sex hormone, lipid, growth factor levels, and CYP17 genotypes were determined. CYP17 genotype was not associated with mammographic density levels before or after adjusting for risk factors for breast cancer. In premenopausal women, the A2 allele was associated with higher levels of dehydroepiandrosterone sulfate, and in postmenopausal women, with higher levels of total estradiol and lower levels of follicle stimulating hormone. Among premenopausal women, interactions were observed between CYP17 genotype and endogenous insulin levels as well as dietary variables associated with mammographic density. Our findings suggest that the CYP17 A2 allele is associated with hormone levels, and interacts with insulin levels and diet to affect breast density levels and potentially breast cancer risk.

Dietary Determinants of Epithelial Ovarian Cancer: A Review of the Epidemiologic Literature

Ovarian cancer is commonly a fatal disease and, despite advances in screening and treatment, the lack of understanding of the underlying etiology has limited prevention strategies. This article reviews the epidemiologic literature on the relationship between consumption of major food groups and the risk of epithelial ovarian cancer (EOC). We identified 7 cohort studies and 27 case-control studies of consumption of major food groups (fruits and vegetables, meats, eggs, fish, dairy products, grains, fats and oils) and EOC risk. Vegetable but not fruit consumption was found to possibly exhibit beneficial effects on the risk of EOC, whereas high meat consumption may be associated with an increased risk. A protective effect on risk of EOC for whole-grain food consumption as well as for consumption of low-fat milk is suggested by the results of the studies. However, evidence for associations of foods such as fish, grains, milk products, and fats and oils with EOC risk is limited and inconsistent, and further examination of these dietary determinants of EOC are warranted. In conclusion, a typical Western diet, which is high in meats and low in vegetables, may be positively associated with ovarian cancer incidence. However, the association between specific dietary factors and EOC risk remains unclear and merits further examination. In particular, future studies need to address the effect of milk products according to fat content and possible biological mechanisms to explain observed effects.

The effect of physiologic hyperinsulinemia during an oral glucose tolerance test on the levels of dehydroepiandrosterone (DHEA) and its sulfate (DHEAS) in healthy young adults born with low and with normal birth weight

Several data support that adrenal hyperandrogenism affects women with low birth weight (LBW). We also found an association between serum dehydroepiandrosterone (DHEA) and fasting insulin levels. The aim of our study was to detect the acute effects of reactive hyperinsulinemia during oral glucose tolerance test (OGTT) on DHEA(S) levels in LBW men and women. Fifty three men and 47 women (of those, 37 men and 33 women were LBW) were enrolled. DHEA, DHEAS, and insulin levels were measured before and during OGTT. Cortisol was also measured. DHEA/cortisol ratio during OGTT was calculated to analyze the acute effect of hyperinsulinemia on DHEA levels. During OGTT, DHEA and cortisol levels decreased in each individual, independently of gender and birth weight. Serum DHEAS decreased to a minor (but significant) extent only in LBW women (p<0.05). The rate of DHEA/cortisol increased in both gender, independently of birth weight. The increase of the rate of DHEA/cortisol during OGTT was associated with maximal insulin response (r = 0.45, p<0.05) and with the insulin(AUC) (r = 0.48, p<0.05) in women. Our results suggest that reactive hyperinsulinemia during OGTT might activate the androgen pathway of adrenal cortex including DHEA production. Therefore acute hyperinsulinemia might counterbalance to some extent the diurnal decrease of DHEA during OGTT.

Central obesity and breast cancer risk: a systematic review

The specific effect of central rather than general obesity on breast cancer risk is not clear. This review examines the relationship between waist and waist-hip ratio (WHR) and risk of breast cancer in pre- and post-menopausal women using all available cohort and case-control data. The databases of the Cochrane Library, Medline, Cancer Lit and Embase were searched until October 2002. Relevant cohort and case-control studies with separate analyses in pre- and/or post-menopausal women were included. Random effects meta-analyses were carried out, subgrouped by pre- or post-menopausal status and cohort or case-control design. Sensitivity analyses were also performed. Five cohort studies with 72,1705 person years of observation (453 pre-menopausal and 2684 post-menopausal cases), and three case-control studies comprising 276 pre-menopausal cases with 758 pre-menopausal controls and 390 post-menopausal cases with 1071 post-menopausal controls were included. Pooled results from cohort studies using the most adjusted data [but without adjustment for weight or body mass index (BMI)] suggest a 39% lower risk of breast cancer in post-menopausal women with the smallest waist (compared with the largest) and a 24% lower risk in women with the smallest WHR. In pre-menopausal women, however, pooled results suggest that measurement of waist or WHR have little effect on risk of breast cancer. Adjustment for BMI abolished the relationship between waist or WHR and risk of post-menopausal breast cancer, but introduced such a relationship amongst pre-menopausal women. The relationship between a smaller measurement of waist or WHR and lower risk of post-menopausal breast cancer appears to result from the associated correlation with BMI. Amongst pre-menopausal women, central (not general) obesity may be specifically associated with an increased risk of breast cancer.

Early carotid atherosclerosis in normotensive severe obese premenopausal women with low DHEA(S)

The aim of this study was to investigate the direct involvement of hyperinsulinaemia, DHEA and DHEA-S [DHEA(S)] in severe obesity in early carotid atherosclerosis, measured as intima-media thickness (IMT). Seventeen normotensive premenopausal women with very high BMI (43.5 +/- 1.6 kg/m2) were recruited for the study. Six women were also evaluated 12 months after laparoscopic adjustable silicone gastric banding (LASGB). Dietary intake, fasting plasma lipid profile, glycemic and insulinemic response to the OGTT, adrenal secretion, at baseline and after ACTH stimulation test, were measured. IMT, common carotid diameter (CD) and left ventricular mass index (LVMi) were measured by B-mode echotomography. All obese subjects showed higher fasting and stimulated insulin levels, but lower DHEA(S) levels than controls, showing a negative correlation between both fasting and stimulated insulin and DHEA(S), either at baseline or after ACTH testing. IMT was higher (p < 0.05) than controls, with a positive correlation with stimulated insulin (p < 0.05) and a strong negative correlation with DHEA(S) (p < 0.001). In a multiple linear regression analysis, insulin response to OGTT maintained an association with DHEA(S) independent of fasting insulin, while DHEA maintained the association with IMT independent of stimulated insulin (p < 0.0001). In the six patients evaluated 12 months after LASGB, fasting insulin levels decreased, while DHEA(S) levels increased (p < 0.05). In conclusion, an early cardiovascular involvement was detected in this group of severe obese with hyperinsulinaemia and low DHEA(S), even in the absence of other well known CVD risk factors.

Androgen receptor gene repeats and indices of obesity in older adults

OBJECTIVE

To examine the relationship between GGN and CAG trinucleotide repeat polymorphisms in the androgen receptor (AR) gene and indices of obesity in older Caucasian adults.

DESIGN

A cross-sectional study.

SUBJECTS

Ninety-nine healthy men (age 51-93 y) and 113 healthy postmenopausal women (age 51-92 y).

MEASUREMENTS

Genotyping the GGN and CAG repeats of the AR gene, and measuring body weight, height and waist and hip circumferences. Waist was measured at the umbilicus (wstumb), iliac crest (wstili), and mid-way between the iliac crest and lowest rib (wstwst). Waist-to-hip ratios (WHRUMB, WHRILI and WHRWST) and body mass index (BMI) were calculated.

RESULTS

Women who were homozygous for a common GGN (17 or 18) and short CAG (</=25) had higher waist and hip circumferences and higher WHRUMB and WHRWST, compared with women without this allele combination. The odds ratios (OR) for the upper 25th percentile of obesity measures were 3.6-5.6-fold higher for wstumb, wstwst, WHRUMB and WHRWST among women with this allele combination. Men who had both a rare GGN (not 17) and short CAG (</=23) had a higher WHRUMB and WHRILI compared with men without this allele combination. The OR related to the upper 10th percentile of obesity measures among men who had this allele combination was 4.7-fold higher for WHRILI.

CONCLUSION

AR GGN and CAG allele combinations are strongly associated with central obesity indices in older adults, particularly in women.

Weight loss in breast cancer patient management

PURPOSE

To systematically review and summarize evidence relevant to obesity and breast cancer clinical outcome, potential hormonal mediating mechanisms, and the current status of weight loss interventions for chronic disease management.

METHODS

A comprehensive, formal literature review was conducted to identify 5,687 citations with key information from 159 references summarized in text and tables. This process included a search for all breast cancer studies exploring associations among survival or recurrence and obesity at diagnosis or weight gain after diagnosis using prospective criteria.

RESULTS

On the basis of observational studies, women with breast cancer who are overweight or gain weight after diagnosis are found to be at greater risk for breast cancer recurrence and death compared with lighter women. Obesity is also associated with hormonal profiles likely to stimulate breast cancer growth. Recently, use of weight loss algorithms proven successful in other clinical settings that incorporate dietary therapy, physical activity, and ongoing behavior therapy have been endorsed by the National Institutes of Health and other health agencies.

CONCLUSION

Although definitive weight loss intervention trials in breast cancer patients remain to be conducted, the current evidence relating increased body weight to adverse breast cancer outcome and the documented favorable effects of weight loss on clinical outcome in other comorbid conditions support consideration of programs for weight loss in breast cancer patients. Recommendations for the clinical care of overweight or obese breast cancer patients are offered.

Effect of low-fat and/or low-energy diets on anthropometric measures in participants of the women's diet study

OBJECTIVE

To compare the effects of low-fat, low-energy and combination low-fat/low-energy intervention on changes in six anthropometric measures in Caucasian and African-American free-living women.

METHODS

The effects of dietary counseling strategies for fat and/or energy reduction were examined on anthropometric measures in 86 pre-menopausal women, average BMI of 28 kg/m2, who participated in a 12-week intervention trial called the Women's Diet Study. The dietary goals were 15% of energy from fat and/or 25% reduction in energy intake, relative to reported baseline intake, using a 2 x 2 factorial design. Analysis of covariance models were constructed to evaluate changes in anthropometric measures over the 12 weeks of study.

RESULTS

The biggest difference by race was in women who were relatively heavier at baseline, in which case African-American women lost significantly less weight but decreased their waist:hip ratio to a significantly greater extent than Caucasian women. With regard to the effects of diet arm, weight loss varied depending on baseline weight, and in women with higher baseline weights, the combination low-fat/low-energy diet resulted in the most weight loss (6.7 kg, p < 0.05). Decreases in the other anthropometric measures at week 12 were more uniform across diet arms and did not depend on baseline values. After controlling for previous weight history and race, the decreases in BMI, percent body fat and waist circumference after 12 weeks were statistically equivalent with the low-fat, low-energy or combination low-fat/low-energy diets. The relatively greater decreases in percent body fat and waist circumference with the combination diet versus the low-fat or low-energy diets were not statistically significant.

CONCLUSION

The low-fat, low-energy and combination diets all resulted in similar and statistically significant decreases in BMI, percent body fat and waist circumference over 12 weeks of intervention. The extent of weight loss, however, varied depending on baseline weight, and the combination diet was the only intervention to result in significant weight loss for women who were heavier at baseline. This indicates that, although there may be an advantage for reducing dietary fat in initially heavier women, any of these counseling strategies could be effective for improving anthropometric predictors of health risks associated with overweight status. This is useful since flexibility in dietary choices may facilitate adherence to dietary counseling in some individuals.

Racial disparities in metabolism, central obesity, and sex hormone-binding globulin in postmenopausal women

Increased total and intraabdominal fat (IAF) obesity as well as other metabolic conditions associated with the insulin resistance syndrome (IRS) are related to low levels of sex hormone-binding globulin (SHBG) in young and older Caucasian (CAU) and young African-American (AA) women. We examined whether postmenopausal AA women, a population with a high incidence of obesity and IRS despite low IAF, would have higher levels of circulating SHBG compared with CAU women, and whether there would be negative relationships between indexes of obesity and risk factors associated with IRS and SHBG levels. We measured body composition, SHBG, free testosterone, leptin, glucose tolerance, insulin, and lipoprotein lipids in 55 CAU (mean +/- SD, 59 +/- 7 yr) and 35 AA (57 +/- 6 yr) sedentary women of comparable obesity (48% body fat, by dual energy x-ray absorptiometry). Compared with CAU women, AA women had larger waist (101 vs. 96 cm), larger fat mass (44.9 +/- 8.8 vs. 39.9 +/- 8.1 kg), larger sc fat area (552 +/- 109 vs. 452 +/- 109 cm(2)), and lower IAF/SC ratio (0.28 +/- 0.12 vs. 0.38 +/- 0.15; P < 0.01), but similar waist to hip ratio (0.83). Both groups had similar SHBG (117 vs. 124 nmol/L) and free testosterone (3.7 vs. 3.4 pmol/L) levels, but AA women had a 35% higher leptin, 34% higher fasting insulin, and 39% greater insulin response to a glucose load (P < 0.05) compared with CAU women. In CAU, but not AA, women SHBG correlated negatively with body mass index (r = -0.28; P < 0.05), waist (r = -0.36; P = 0.01), IAF (r = -0.34; P = 0.01), and insulin response to oral glucose (r = -0.37; P < 0.05) and positively with high density lipoprotein cholesterol (r = 0.30; P = 0.03). The relationship between insulin area and SHBG in CAU women disappeared after adjusting for IAF, whereas the relationship between high density lipoprotein cholesterol and SHBG persisted after adjusting for IAF, but not for fat mass. Leptin was positively related to fat mass (P < 0.05) in both groups, but it was related to insulin only in the Caucasian women (P< 0.01). There was a racial difference in the slopes (P< 0.05) of the relationships of leptin to fat mass (P < 0.05). Racial differences in leptin disappeared after adjustment for fasting insulin. These results suggest that the metabolic relationships between total and regional obesity, glucose, and lipid metabolism with SHBG in CAU women are different from those in postmenopausal obese AA women.

Association of increased C-peptide serum levels and testosterone in type 2 diabetes

Background: The purpose of our study was to investigate the association of C-peptide and steroid hormones in males and females with type 2 diabetes compared to controls. Methods: In 562 subjects, matched for age and body mass index (BMI), 126 female type 2 diabetic patients (known diabetes duration: 7.8+/-0.8 years, HbA(1c): 7.6+/-0.14%), 126 healthy female subjects, 155 male type 2 diabetic patients (known diabetes duration: 6.4+/-0.6 years, HbA(1c): 7.7+/-0.11%), and 155 healthy male controls, C-peptide levels and serum levels of steroid hormones (progesterone, cortisol, DHEAS, estradiol, and testosterone) were measured by immunometric assays. Ratios of steroid hormones were calculated to investigate shifts in steroidogenesis. Results: In female patients, testosterone was significantly higher than in controls (1.7+/-0.1 vs. 1.4+/-0.2 pmol/l; P<0.05), something that was also demonstrated for the ratio of testosterone/estradiol (P<0.05). In male patients, lower levels of testosterone (11.8+/-0.5 vs. 14.3+/-0.5 pmol/l; P<0.05) and higher cortisol levels (257.5+/-9.9 vs. 228.2+/-7.9 µmol/l, P<0.01) were found than in controls. The progesterone/DHEAS ratio (P<0.05) and the progesterone/testosterone ratio (P<0.001) were significantly higher and DHEAS/cortisol significantly lower in type 2 diabetic males than in controls. In a multiple linear regression analysis that controlled for age, BMI, C-peptide, HDL-cholesterol, and HbA(1c), testosterone was significantly and positively correlated with C-peptide levels in female (P<0.05) but not in male type 2 diabetic patients. Conclusions: Testosterone levels were higher in female patients than in controls and correlated with C-peptide levels while testosterone levels were lower in male patients than in controls and showed no correlation with C-peptide. A higher ratio of testosterone/estradiol in type 2 diabetic females and of progesterone/DHEAS and progesterone/testosterone in type 2 diabetic males than in controls may indicate gender-dependent shifts in steroidogenesis. Whether the shifts in steroidogenesis contribute to insulin resistance in diabetic patients should be the subject of further studies.

Testosterone, androstenedione and dihydrotestosterone concentrations are elevated in female patients with major depression

Hyperactivity of the HPA-system in major depression is reflected by an increased secretion of adrenal hormones especially cortisol and dehydroepiandrosterone (DHEA). In women for whom androgenicity is associated with cardiovascular disorders the dominant source of androstenedione and testosterone secretion are the adrenal glands. To date, there is only sparse information about the regulation of androstenedione, testosterone and dihydrotestosterone (DHT) concentrations in women with severe major depression.Therefore, 11 pre- and postmenopausal, severely depressed, hypercortisolemic women (Hamilton Depression Scale, 31.3+/-5.9; age, 28-77 yrs; mean, 48. 1+/-18.1 yrs) and 11 age-matched healthy female controls (age, 24-81 yrs; mean, 47.9+/-21.5 yrs) underwent a 24 hour (h) blood sampling starting at 0800 h with 30-minute sampling intervals. By applying multivariate analysis of covariance with age as covariate, androstenedione, testosterone and DHT plasma levels at 0900 h show a trend for elevated concentrations in depressed women compared to controls (F(1,19)=2.7; P=0.057). Univariate F tests reveal a significant difference between the groups for androstenedione (4. 19+/-1.571 vs 2.584+/-1.257 nmol/l; P<0.05) testosterone (1.110+/-0. 278 vs 0.833+/-0.347 nmol/l; P<0.05) and DHT (0.656+/-0.207 vs 0. 483+/-0.242 nmol/l; P<0.05). Mean ACTH (16.4+/-10.4 vs 10.4+/-2.4 pmol/l; P=0.89), LH (13.5+/-11.8 vs 8.9+/-9.2 IU/l; P=0.12), FSH (35. 2+/-33.1 vs 31.3+/-35.7 IU/l; P=0.67) and estradiol (135.4+/-157.4 vs 82.2+/-85.1 pmol/l; P=0.20) plasma levels did not differ between patients and controls. Further, there was a trend towards an age related decline in testosterone secretion in healthy controls (r=-0. 24; P=0.08) which did not occur in depressed patients (r=0.17; P=0. 96), while the calculated ratio of DHEA to testosterone was similar in both groups (0.2+/-0.14 vs 0.13+/-0.7; P=0.21, unpaired t-test). In conclusion, androstenedione, testosterone and DHT concentrations all were increased in hypercortisolemic women with severe major depression. These findings are best explained as a consequence of an overstimulation of the adrenal glands through pituitary and hypothalamic sites of the HPA-system.

Vascular wall function in insulin-resistant JCR:LA-cp rats: role of male and female sex

Vascular wall function was assessed in obese insulin-resistant (cp/cp) and lean normal (+/?), male and female, JCR:LA-cp rats. Both male and female cp/cp rats showed enhanced maximum contractility in response to norepinephrine; impaired smooth muscle in response to sodium nitroprusside, a nitric oxide (NO) donor; and impaired relaxation in response to acetylcholine (ACh), compared with their lean counterparts. The abnormalities were similar in male and female cp/cp rats. The NO synthase inhibitor, Nomega-nitro-L-arginine methyl ester (L-NAME), inhibited ACh-mediated relaxation significantly in male rats, both cp/cp and +/?. The inhibition of ACh-mediated relaxation by L-NAME in +/? females was less, with no reduction in maximal relaxation, and was absent in cp/cp females. These effects suggest that the relative importance of NO in the endothelial modulation of smooth muscle contractility is greater in male rats. The results are consistent with a decreased role for endothelial NO in the cp/cp rats of both sexes and a reduction in NO-independent cholinergic relaxation in the male cp/cp rat. This NO-independent mechanism is not affected in the female cp/cp rats. The relatively small differences between males and females in smooth muscle cell and vascular function may contribute to sex-related differences in the atherogenesis, vasospasm, and ischemic damage associated with the obese insulin-resistant state.

Duration of obesity and risk of non-insulin-dependent diabetes mellitus

Although obesity is one of the major risk factors for diabetes mellitus, the association of the duration of obesity with glucose intolerance or insulin dysregulation has not yet been clarified. Thirteen articles were picked up from the MEDLINE database by using the four key-word phrases, "duration of obesity," "duration of overweight," "prolonged obesity," and "prolonged overweight." Although the definition of overweight was similar among the children-based studies (> = 20% or 2 SD over ideal weight), the cutoff point for adults ranged from 25.0 to 30.0 kg/m2 of body mass index. With regard to the definition of the duration of obesity, the articles were roughly divided into two groups, with some researchers bearing the definition on the number of years from the onset of overweight and some calculating using the person-years method. The prevalence or incidence of non-insulin-dependent diabetes mellitus (NIDDM) or impaired glucose tolerance (IGT) are probably associated with the duration of obesity. The effect of prolonged obesity on insulin dysregulation is still unclear.