Sex hormones and sexual function in obese men losing weight

Does weight loss improve semen quality and reproductive hormones? Results from a cohort of severely obese men

Background

A high body mass index (BMI) has been associated with reduced semen quality and male subfecundity, but no studies following obese men losing weight have yet been published. We examined semen quality and reproductive hormones among morbidly obese men and studied if weight loss improved the reproductive indicators.

Methods

In this pilot cohort study, 43 men with BMI > 33 kg/m² were followed through a 14 week residential weight loss program. The participants provided semen samples and had blood samples drawn, filled in questionnaires, and had clinical examinations before and after the intervention. Conventional semen characteristics as well as sperm DNA integrity, analysed by the sperm chromatin structure assay (SCSA) were obtained. Serum levels of testosterone, estradiol, sex hormone-binding globulin (SHBG), luteinizing hormone (LH), follicle-stimulating hormone (FSH), anti-Müllerian hormone (AMH) and inhibin B (Inh-B) were measured.

Results

Participants were from 20 to 59 years of age (median = 32) with BMI ranging from 33 to 61 kg/m². At baseline, after adjustment for potential confounders, BMI was inversely associated with sperm concentration (p = 0.02), total sperm count (p = 0.02), sperm morphology (p = 0.04), and motile sperm (p = 0.005) as well as testosterone (p = 0.04) and Inh-B (p = 0.04) and positively associated to estradiol (p < 0.005). The median (range) percentage weight loss after the intervention was 15% (3.5 - 25.4). Weight loss was associated with an increase in total sperm count (p = 0.02), semen volume (p = 0.04), testosterone (p = 0.02), SHBG (p = 0.03) and AMH (p = 0.02). The group with the largest weight loss had a statistically significant increase in total sperm count [193 millions (95% CI: 45; 341)] and normal sperm morphology [4% (95% CI: 1; 7)].

Conclusion

This study found obesity to be associated with poor semen quality and altered reproductive hormonal profile. Weight loss may potentially lead to improvement in semen quality. Whether the improvement is a result of the reduction in body weight per se or improved lifestyles remains unknown.

Comparing effects of a low-energy diet and a high-protein low-fat diet on sexual and endothelial function, urinary tract symptoms, and inflammation in obese diabetic men

INTRODUCTION

Abdominal obesity and type 2 diabetes mellitus are associated with sexual and endothelial dysfunction, lower urinary tract symptoms (LUTS), and chronic systemic inflammation.

AIM

To determine the effects of diet-induced weight loss and maintenance on sexual and endothelial function, LUTS, and inflammatory markers in obese diabetic men.

MAIN OUTCOME MEASURES

Weight, waist circumference (WC), International Index of Erectile Function (IIEF-5) score, Sexual Desire Inventory (SDI) score, International Prostate Symptom Scale (IPSS) score, plasma fasting glucose and lipids, testosterone, sex hormone binding globulin (SHBG), inflammatory markers (high-sensitivity C-reactive protein [CRP] and interleukin-6 [IL-6]) and soluble E-selectin, and brachial artery flow-mediated dilatation (FMD) were measured at baseline, 8 weeks, and 52 weeks.

METHODS

Over 8 weeks, 31 abdominally obese (body mass index ≥ 30 kg/m(2) , WC ≥ 102 cm), type 2 diabetic men (mean age 59.7 years) received either a meal replacement-based low-calorie diet (LCD) ∼1,000 kcal/day (N = 19) or low-fat, high-protein, reduced-carbohydrate (HP) diet (N = 12) prescribed to decrease intake by ∼600 kcal/day. Subjects continued on, or were switched to, the HP diet for another 44 weeks.

RESULTS

At 8 weeks, weight and WC decreased by ∼10% and ∼5% with the LCD and HP diet, respectively. Both diets significantly improved plasma glucose, low-density lipoprotein (LDL), SHBG, IIEF-5, SDI and IPSS scores, and endothelial function (increased FMD, reduced soluble E-selectin). Erectile function, sexual desire, and urinary symptoms improved by a similar degree with both diets. CRP and IL-6 decreased with the HP diet. At 52 weeks, reductions in weight, WC, and CRP were maintained. IIEF-5, SDI, and IPSS scores improved further.

CONCLUSIONS

Diet-induced weight loss induces rapid improvement of sexual, urinary, and endothelial function in obese diabetic men. A high-protein, carbohydrate-reduced, low-fat diet also reduces systemic inflammation and sustains these beneficial effects to 1 year.

Lifestyle/dietary recommendations for erectile dysfunction and female sexual dysfunction

Sexual problems are diffuse in both genders. Although epidemiologic evidence seems to support a role for lifestyle factors in erectile dysfunction, limited data are available suggesting the treatment of underlying risk factors may improve erectile dysfunction. The results are sparse regarding associations between lifestyle factors and female sexual dysfunction, and conclusions regarding influence of healthy behaviors on female sexual dysfunction cannot be made before more studies have been performed. Beyond the specific effects on sexual dysfunctions in men and women, adoption of these measures promotes a healthier life and increased well-being, which may help reduce the burden of sexual dysfunction.

The moderating impact of lifestyle factors on sex steroids, sexual activities and aging in Asian men

The present study sought to evaluate the relative associations of exercise, sleep and other lifestyle habits with aging, sex hormones, percent body fat (%BF) and sexual activities in men living in the community. A better understanding of this complex interrelationship is important in helping the formulation of modalities for a holistic approach to the management of aging men. The results showed that age is a major determinant for many physiological parameters, including sleep, hormonal and metabolic parameters, some lifestyle factors and sexual activities. Testosterone (T), bioavailable testosterone (BioT) and dehydroepiandrosterone sulphate (DHEAS) concentrations decreased with age, while estradiol (E2), sex hormone-binding globulin (SHBG) and %BF increased with age. In addition, there exist intricate associations among hormonal and lifestyle factors, %BF and age. High-intensity exercise and longer duration of sleep were associated with higher concentrations of T and BioT. T was shown to be associated positively with men who were engaged in masturbation. DHEAS was associated with men wanting more sex and with good morning penile rigidity. Older Singaporean men tended to sleep for shorter duration, but exercised more intensely than younger men. Coital and masturbation frequencies decreased with age, and a significantly greater number of younger men were engaged in masturbation. Relationship between the partners is a key determinant of sexuality in men. It appears that T may have a limited, while dehydroepiandrosterone (DHEA) have a greater role than previously suggest, as a motivational signal for sexual function in men. Both biological and psychosocial factors interact with each other to influence sexual functions in men. Hence, a biopsychosocial approach may be more appropriate for a more lasting resolution to sexual dysfunctions in men.

Men's sexual health and the metabolic syndrome

The aim of this article is to provide an overview of the current literature on the impact of the metabolic syndrome on male sexual health and current developments in the management of sexually dysfunctional men with a metabolic syndrome. The increasing prevalence across the world of the metabolic syndrome-a cluster of cardiovascular disease risk factors-causes the metabolic syndrome to be considered the most important threat to male sexual health of the 21st century. It has been shown to have a negative impact on male sexual function through its relationship with cardiovascular disease risk, its association with hypogonadism, and associated psychosocial factors. Besides established pharmacological and hormonal interventions, lifestyle modification programs are considered important therapeutic tools.

Obesity: modern man's fertility nemesis

The obesity pandemic has grown to concerning proportions in recent years, not only in the Western World, but in developing countries as well. The corresponding decrease in male fertility and fecundity may be explained in parallel to obesity, and obesity should be considered as an etiology of male fertility. Studies show that obesity contributes to infertility by reducing semen quality, changing sperm proteomes, contributing to erectile dysfunction, and inducing other physical problems related to obesity. Mechanisms for explaining the effect of obesity on male infertility include abnormal reproductive hormone levels, an increased release of adipose-derived hormones and adipokines associated with obesity, and other physical problems including sleep apnea and increased scrotal temperatures. Recently, genetic factors and markers for an obesity-related infertility have been discovered and may explain the difference between fertile obese and infertile obese men. Treatments are available for not only infertility related to obesity, but also as a treatment for the other comorbidities arising from obesity. Natural weight loss, as well as bariatric surgery are options for obese patients and have shown promising results in restoring fertility and normal hormonal profiles. Therapeutic interventions including aromatase inhibitors, exogenous testosterone replacement therapy and maintenance and regulation of adipose-derived hormones, particularly leptin, may also be able to restore fertility in obese males. Because of the relative unawareness and lack of research in this area, controlled studies should be undertaken and more focus should be given to obesity as an etiolgy of male infertility.

Testosterone and type 2 diabetes

PURPOSE OF REVIEW

To describe the relationship between testosterone levels and type 2 diabetes (T2D).

RECENT FINDINGS

Multiple epidemiological studies have shown that low testosterone levels are associated with and predict the future development of T2D and the metabolic syndrome. Although this relationship is confounded by the association of total testosterone with sex hormone-binding globulin, free testosterone remains associated with measures of insulin resistance and T2D in some, but not all studies. Although the link between low testosterone levels and insulin resistance is not solely a consequence of adiposity, current studies suggest that a substantial component is mediated through its association with body fat, in particular abdominal visceral adipose tissue. This testosterone-fat relationship is bi-directional, as both weight loss and testosterone therapy increase testosterone levels, reduce fat mass, and decrease insulin resistance.

SUMMARY

Low testosterone levels are very commonly found in men with T2D and are associated with aging and obesity. Whether testosterone treatment in men with T2D decreases insulin resistance above that attributable to its fat-reducing effect is currently unknown. Future studies should compare testosterone treatment with lifestyle changes (exercise and weight loss measures), and other insulin-sensitizing agents. Until further evidence is available, testosterone therapy outside clinical trials should be reserved for diabetic men with unequivocal hypogonadism.

Effects of a low-energy diet on sexual function and lower urinary tract symptoms in obese men

OBJECTIVE

Abdominal obesity and type 2 diabetes mellitus are associated with erectile and urinary dysfunction in men. The extent to which sexual function and lower urinary tract symptoms (LUTSs) are improved by weight loss remains unclear.

SUBJECTS

We compared the effects of 8 weeks of a low-calorie diet using meal replacements (Kicstart) on insulin sensitivity, plasma testosterone levels, erectile function (measured by the five-item version of the International Index of Erectile Function, IIEF-5), sexual desire (measured by the Sexual Desire Inventory, SDI) and LUTS (measured by the International Prostate Symptom Score, IPSS), in abdominally obese (body mass index >or=30 kg m(-2), waist circumference (WC) >or=102 cm) men (mean age 49.7 years) with uncomplicated diet or oral hypoglycemic-treated type 2 diabetes mellitus (n = 19) or without type 2 diabetes mellitus (n=25), with a control group of nondiabetic men (n = 26) with similar body mass index and WC.

RESULTS

Weight loss of ∼ 10% was significantly associated with increased insulin sensitivity, plasma testosterone levels, IIEF-5 and SDI scores, as well as reduced WC and IPSS scores, in diabetic as well as nondiabetic men. The degree of weight loss was significantly associated with improvements in plasma testosterone levels (r = -0.34), erectile function (r = -0.26) and LUTS (r=0.65). Reduction in LUTS was significantly associated with increased plasma testosterone (r = -0.35), erectile function (r = -0.42) and sexual desire (r = -0.40).

CONCLUSIONS

Diet-induced weight loss significantly and rapidly improves sexual function, and reduces LUTS, in obese middle-aged men with or without diabetes.

Long-term effects of calorie restriction on serum sex-hormone concentrations in men

Calorie restriction (CR) slows aging and consistently reduces circulating sex hormones in laboratory animals. However, nothing is known regarding the long-term effects of CR with adequate nutrition on serum sex-hormone concentration in lean healthy humans. In this study, we measured body composition, and serum total testosterone, total 17-beta-estradiol, sex hormone-binding globulin (SHBG), and dehydroepiandrosterone sulfate (DHEA-S) concentrations in 24 men (mean age 51.5 +/- 13 years), who had been practicing CR with adequate nutrition for an average of 7.4 +/- 4.5 years, in 24 age- and body fat-matched endurance runners (EX), and 24 age-matched sedentary controls eating Western diets (WD). We found that both the CR and EX volunteers had significantly lower body fat than the WD volunteers (total body fat, 8.7 +/- 4.2%; 10.5 +/- 4.4%; 23.2 +/- 6.1%, respectively; P = 0.0001). Serum total testosterone and the free androgen index were significantly lower, and SHBG was higher in the CR group than in the EX and WD groups (P < or = 0.001). Serum 17beta-estradiol and the estradiol:SHBG ratio were both significantly lower in the CR and EX groups than in the WD group (P < or = 0.005). Serum DHEA-S concentrations were not different between the three groups. These findings demonstrate that, as in long-lived CR rodents, long-term severe CR reduces serum total and free testosterone and increases SHBG concentrations in humans, independently of adiposity. More studies are needed to understand the role of this CR-mediated reduction in sex hormones in modulating the pathogenesis of age-associated chronic diseases such as cancer and the aging process itself.

Obesity and testicular function

Obesity in men, particularly when central, is associated with lower total testosterone [TT], free testosterone [FT] and sex hormone-binding globulin [SHBG], and a greater decline in TT and FT with increasing age compared with lean men. Obesity-related conditions such as obstructive sleep apnea, insulin resistance and type 2 diabetes mellitus are independently associated with decreased plasma testosterone. Possible mechanisms include decreased LH pulse amplitude, inhibitory effects of oestrogen at the hypothalamus and pituitary and the effects of leptin and other peptides centrally and on Leydig cells. Obese men have reduced sperm concentration and total sperm count compared to lean men but sperm motility and morphology appear unaffected. The cause and effect relationships between low plasma androgen levels, obesity and the metabolic syndrome, and associated cardiometabolic risk remain unclear. While weight loss normalizes TT and FT in obese men, androgen replacement in the short term does not significantly improve cardiometabolic risk profile despite reducing fat mass.

The effect of obesity on sperm disorders and male infertility

The results of several studies point to an increased likelihood of abnormal semen parameters among overweight men, and an elevated risk for subfertility among couples in which the male partner is obese. Obesity is, therefore, associated with a higher incidence of male factor infertility. Several mechanisms might account for the effect of obesity on male infertility, both directly and indirectly, by inducing sleep apnea, alterations in hormonal profiles (reduced inhibin B and androgen levels accompanied by elevated estrogen levels) and increased scrotal temperatures, ultimately manifesting as impaired semen parameters (decreased total sperm count, concentration and motility; increased DNA fragmentation index). Neither the reversibility of obesity-associated male infertility with weight loss nor effective therapeutic interventions have been studied in-depth. The increasing prevalence of obesity calls for greater clinical awareness of its effects on fertility, better understanding of underlying mechanisms, and exploration into avenues of treatment.

Erectile dysfunction and hormonal imbalance in morbidly obese male is reversed after gastric bypass surgery: a prospective randomized controlled trial

The effects of weight loss on erectile function and hormones have not been well studied. The aim of this study was to measure the degree to which sexual function and in particular erectile function and hormonal environment change after substantial weight loss, surgically and non-surgically induced in the morbidly obese male in a prospective randomized long-term controlled trial. Furthermore, how surgery makes a difference when treating morbidly obese men was envisaged in this context. We prospectively studied 20 morbidly obese men for 24 months, divided into two groups: group A included 10 patients who underwent life style modifications (exercise and diet) for 4 months and subsequently gastric bypass, and another 10 patients in group B were kept on weekly follow-up. None of the men were taking phosphodiesterase type-5 inhibitors. All patients underwent International Index of Erectile Function (IIEF)-5 questionnaire, serum oestradiol, prolactin (PRL), luteinizing (LH) and follicle-stimulating (FSH) hormones, free and total testosterone (FT and TT) at baseline (time 0), surgery - 4 months latter baseline (time 1) and final evaluation - 24 months (time 2). From times 0 to 1, group A presented a mean body mass index (BMI) reduction of 12.6 (p < 0.0001), whereas group B, 2.1 (p > 0.05). The BMI reductions between times 0 and 2 were 24.7 (p < 0.0001) and 0.7 (p > 0.05) for groups A and B respectively. BMI average between the two groups was similar at time 0 (p = 0.2142), and different at times 1 (p = 0.0033) and 2 (p < 0.0006). Increase in IIEF-5 score (p = 0.0469), TT (p = 0.0349) and FSH levels (p = 0.0025), and reduction in PRL level (p < 0.0001) were observed in group A from times 0 to 2 and 1 to 2. There were no changes from times 0 to 1. Comparing groups A and B at time 2, IIEF-5, TT and FT increased significantly in group A (p = 0.0224, 0.0043 and 0.0149 respectively). Surgery-induced weight loss increased erectile function quality measured by IIEF-5 questionnaire, increased TT, FT and FSH and reduced PRL levels. The hormonal impact verified could justify the improvement in erectile function. Lifestyle modifications impacted BMI without hormonal or sexual impact in morbidly obese. New studies are warranted in the field to support our data.

An aromatase polymorphism modulates the relationship between weight and estradiol levels in obese men

OBJECTIVE

To describe the influence of the TTTA aromatase polymorphism (TTTAn) on the relation between obesity and plasma estradiol (E(2)) in obese men.

DESIGN

A 2-year cohort study.

SETTING

Clinical research center.

PATIENT(S)

Severely obese men (31 who had had gastric bypass surgery and 118 controls).

INTERVENTION(S)

Men were genotyped for the TTTAn CYP19A1 polymorphism. Anthropomorphic measures, plasma E(2), and other hormonal levels were determined at baseline and 2-year follow-up.

MAIN OUTCOMES MEASURE(S)

Relationships between weight and changes in weight and plasma E(2) were examined in relation to the TTTAn polymorphism.

RESULT(S)

The mean age was 46.5 ± 10.82 years, and mean body mass index was 47.1 ± 8.46 kg/m(2). The most common repeats were 7 and 11. TTTAn number did not correlate with plasma E(2) in the univariate analysis. When patients were stratified per weight group, the correlation between plasma E(2) and weight was seen only among men with a higher TTTA repeat at baseline and 2 years. Similarly, only men with higher TTTA exhibited reduced E(2) levels after weight loss.

CONCLUSION(S)

A higher TTTA repeat is associated with a strengthened relationship between obesity and E(2). The well-established effect of increased weight on plasma E(2) appears to be absent in men with low TTTA numbers.

Effect of Roux-en-Y gastric bypass surgery on the sex steroids and quality of life in obese men

CONTEXT

The effect of bariatric surgery on the reproductive function of obese men is not entirely elucidated.

OBJECTIVE

The aim of the study was to define the effect of Roux-En-Y gastric bypass surgery on the reproductive hormones and sexual function in obese men.

DESIGN AND SETTING

The cohort was followed for 2 yr at a clinical research center.

PATIENTS

Sixty-four severely obese men (22 who had gastric bypass surgery and 42 controls) participated in the study.

INTERVENTION(S)

Anthropometrics [weight, body mass index (BMI), and percentage body fat] and reproductive hormones were measured. The sexual quality of life was assessed using the Impact of Weight on the Quality Of Life-Lite questionnaire.

MAIN OUTCOME MEASURE(S)

Reproductive hormones and sexual quality of life were measured.

RESULTS

The mean age was 48.9 +/- 1.2 yr. At baseline, mean weight was 333.0 +/- 7.1 lb, BMI was 46.2 +/- 0.9 kg/m(2), and total testosterone was 339.9 +/- 21.32 ng/dl. BMI correlated positively with estradiol and negatively with total and free testosterone. Indices of dissatisfaction with sexual quality of life correlated positively with measures of obesity. Difficult sexual performance and low sexual desire correlated negatively with free and total testosterone (r = -0.273, P = 0.038; and r = -0.267, P = 0.042, respectively). After 2 yr, the gastric bypass surgery group had a significant decrease in BMI (-16.6 +/- 1.2 vs. -0.46 +/- 0.51 kg/m(2)) and estradiol (-8.1 +/- 2.4 vs. 1.6 +/- 1.4 pg/ml) and had an increase in total testosterone (310.8 +/- 47.6 vs. 14.2 +/- 15.3 ng/dl) and free testosterone (45.2 +/- 5.1 vs. -0.4 +/- 3.0 pg/ml). Sexual quality of life was improved after gastric bypass surgery.

CONCLUSION

Hormonal alterations and diminished sexual quality of life among obese men are related to degree of obesity, and both are improved after gastric bypass surgery.

Androgen receptor gene polymorphism and the metabolic syndrome in 60-80 years old Norwegian men

The metabolic syndrome (MS) includes a clustering of metabolic derangements. Low testosterone levels have been shown to be associated with both components of MS and MS per se. As most androgen-related effects are mediated thorough the androgen receptor (AR), we wanted to investigate to which degree the AR CAG and GGN repeat polymorphisms might be related to MS. Sixty-eight men, 60-80 years old, with subnormal total testosterone levels (<or=11.0 nmol/L) and 104 men with normal levels (>11.0 nmol/L), participating in a nested case-control study were investigated in this study. Body weight, height, waist circumferences and blood pressure were measured. Fasting blood samples were drawn and an oral glucose tolerance test (OGTT) was performed. The CAG and GGN polymorphisms in the AR gene were determined by direct sequencing of leucocyte DNA. Men with MS had lower CAG repeat number than healthy men (p = 0.007). There were, however, no difference in CAG or GGN repeats length between the groups with subnormal or normal testosterone concentrations. In cross-sectional analyses, men with CAG repeat lengths <or= 21 had significantly higher fasting glucose, C-peptide and glycosylated haemoglobin (HbA1c) levels (all p < 0.05). In multiple regression analyses, CAG repeat length was an inverse and independent predictor of glucose after an OGTT and of HbA1c levels. We also found that men with more than one component of MS had shorter CAG repeat number (p for trend 0.013) than those with only one component. In conclusion, there were no associations with GGN repeat length, while short CAG repeat length seems to be associated with increased risk of MS.

Impact of male obesity on infertility: a critical review of the current literature

OBJECTIVE

To evaluate the current understanding of the effects and potential mechanisms of obesity on male fertility.

DESIGN

Literature review of articles pertaining to obesity and male infertility.

RESULT(S)

Recent population-based studies suggest an elevated risk for subfertility among couples in which the male partner is obese and an increased likelihood of abnormal semen parameters among heavier men. Male factor infertility is associated with a higher incidence of obesity in the male partner. Obese men exhibit reduced androgen and SHBG levels accompanied by elevated estrogen levels. Reduced inhibin B levels correlate with degree of obesity and are not accompanied by compensatory increases in FSH. This complexly altered reproductive hormonal profile suggests that endocrine dysregulation in obese men may explain the increased risk of altered semen parameters and infertility. Additional features of male obesity that may contribute to an increased risk for infertility are altered retention and metabolism of environmental toxins, altered lifestyle factors, and increased risks for sexual dysfunction. Neither reversibility of obesity-associated male infertility with weight loss nor effective therapeutic interventions have been studied yet.

CONCLUSION(S)

The increasing prevalence of obesity calls for greater clinician awareness of its effects on fertility, better understanding of underlying mechanisms, and eventually avenues for mitigation or treatment.

Inverse association of testosterone and the metabolic syndrome in men is consistent across race and ethnic groups

CONTEXT

Low sex hormone levels have been associated with the metabolic syndrome (MetS).

OBJECTIVES

Our objective was to determine whether the association between sex hormone levels and MetS varies by race/ethnicity among men and to investigate the relationship of sex hormones and individual components of MetS.

DESIGN

We conducted a population-based observational survey.

PARTICIPANTS

A multistage stratified design was used to recruit a random sample of 2301 racially/ethnically diverse men age 30-79 yr. Blood samples were obtained on 1899 men. Analyses were conducted on 1885 men with complete data on total testosterone (T), free T, and SHBG.

INTERVENTIONS

There were no interventions.

MAIN OUTCOME MEASURE

MetS was defined using a modification of the Adult Treatment Panel III guidelines. The association between MetS and sex hormone levels was assessed using odds ratios and 95% confidence intervals estimated using logistic regression models.

RESULTS

A strong inverse association was observed, in both bivariate and multivariate analyses, between hormone levels and MetS. The odds of MetS increased about two-fold with a 1 sd decrease in hormone levels. The association between sex hormones and MetS was statistically significant across racial/ethnic groups. Although the magnitude of this association was largest among White men, racial/ethnic differences were not statistically significant. The strength of the association of sex hormones with individual components of MetS varied; stronger associations were observed with waist circumference and dyslipidemia and more modest associations with diabetes and elevated blood sugar.

CONCLUSIONS

A robust, dose-response relationship between sex hormone levels and odds of the metabolic syndrome in men is consistent across racial/ethnic groups.

Improvements in sexual quality of life after moderate weight loss

We evaluated changes in sexual quality of life as they relate to weight loss over a 2-year period in individuals undergoing weight loss treatment. Six dimensions of sexual quality of life were measured using items from the Impact of Weight on Quality of Life questionnaire (feeling sexually unattractive, lacking sexual desire, reluctance to be seen undressed, difficulty with sexual performance, avoidance of sexual encounters and lack of enjoyment of sexual activity). At baseline women were more likely than men to report lack of sexual enjoyment and reluctance to be seen undressed in spite of lower body mass index (BMI). Weight loss averaged 13.1% and was significantly associated with improvements in all sexual quality of life dimensions. A 3-4% regain did not appear to negatively affect sexual quality of life. The greatest improvements for women had occurred by 3 months and were observed in all dimensions, whereas for men only 'not feeling sexually attractive' showed marked improvement in this short time frame.

Erectile dysfunction: does insulin resistance play a part?

OBJECTIVE

To review MEDLINE literature for correlations between insulin resistance and erectile dysfunction (ED).

DESIGN

MEDLINE literature review (1966 to present).

SETTING

Academic medical center.

PATIENT(S)

None.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

None.

RESULT(S)

Erectile dysfunction affects more than half of men over the age of 40. Fortunately, most men with ED can be successfully treated with phosphodiesterase 5A (PDE-5) inhibitors, which up-regulate the vasodilatory effects of nitric oxide (NO). Insulin resistance affects 25% of U.S. adults and increases to a 60% occurrence in individuals who are overweight. Endothelial dysfunction, which is associated with insulin resistance states, can cause disturbances in the subcellular signaling pathways required for NO production. Because endothelial production of NO and insulin sensitivity are positively related in healthy humans, the relationships among insulin resistance, NO, and ED are the target of this review of MEDLINE literature.

CONCLUSION(S)

Insulin resistance states are characterized by defective vascular NO production and impaired insulin-induced vasodilation, both of which are likely to cause ED. Diagnosing and treating insulin resistance should be part of the initial management plan for ED. Future studies concerning the cause and effect relationship of insulin resistance and ED should be implemented.

Serum testosterone level and related metabolic factors in men over 70 years old

BACKGROUND

Sex hormone decline remarkably decreases metabolic function in elderly men. Many degenerative diseases may relate to testosterone deficiency.

OBJECTIVE

To evaluate the serum testosterone concentration in elderly men, its related metabolic and inflammatory factors, and the relationship of metabolic syndrome to testosterone levels.

METHODS

381 elderly men (78.8+/-4.1 yr old) residing in a veterans' nursing home were enrolled. We measured body height and weight, waist and hip circumferences, body fat, blood pressure, blood glucose and insulin, glycosylated hemoglobin (HbA1c), lipid profile, complete blood count, high sensitivity C-reactive protein (hsCRP), total testosterone, and SHBG. Free testosterone was calculated by Nanjee-Wheeler's method.

RESULTS

Serum total testosterone levels were 0.20-15.74 ng/ml (free testosterone 11.78-478.31 pmol/l). Total testosterone correlated negatively with body mass index (BMI), waist-hip ratio, body fat, blood glucose, blood insulin, HbA1c, serum triglyceride, white blood cell (WBC) count and hsCRP; but positively with HDL-cholesterol (HDL-C) and hemoglobin. Multiple regression stepwise forward analysis revealed that BMI values, fasting blood glucose, WBC count, fasting hsCRP and hemoglobin were independent factors related to total testosterone. Furthermore, total testosterone is lower in elderly men with metabolic syndrome, according to National Cholesterol Education Program criteria with a modification of waist circumference. However, free testosterone plays a small role in association with metabolic factors in this elderly men's population.

CONCLUSION

Total testosterone level is significantly related to metabolic and inflammatory factors in elderly men. Low total testosterone may be a significant indicator for development of metabolic syndrome in elderly men.

Sexual function and obesity

OBJECTIVE

To review the literature on the relationship between obesity and sexual function.

METHOD

A search in the medical literature from 1966 and onwards was carried out through Medline and Embase for publications on obesity, in combination with Medical Subject Heading words related to sexual function and dysfunction.

COMMENTS

Four prospective and seven cross-sectional studies were found describing association between obesity and erectile dysfunction (ED). One cross-sectional study was found describing obesity and female sexual dysfunction (FSD). The prospective studies on ED all demonstrated a direct association and so did five of the seven cross-sectional studies. The single FSD study did not find any relationship. Eight intervention studies on weight loss and sexual difficulties were identified. All included few individuals and results were mixed even if most indicated an increase of sexual activity among both men and women after weight loss intervention.

CONCLUSION

Support for the assumption that obesity is associated with ED was found in both prospective and cross-sectional studies. FSD was not adequately described in the literature and prospective studies are needed here. Results from weight loss intervention studies are less conclusive, but also point toward improvement in sexual dysfunction with reduced weight.

Testosterone and erectile function: from basic research to a new clinical paradigm for managing men with androgen insufficiency and erectile dysfunction

OBJECTIVES

Androgens are essential for the development and growth of the penis, and they regulate erectile physiology by multiple mechanisms. Our goal is to provide a concise overview of the basic research and how this knowledge can be translated into a new clinical paradigm for patient management. In addition, this new paradigm may serve as a basis for stimulating constructive debate regarding the use of testosterone in men, and to promote new, innovative basic and clinical research to further understand the underlying mechanisms of androgen action in restoring erectile physiology.

METHODS

A literature review was performed utilizing the US National Library of Medicine's PubMed database.

RESULTS

On the basis of evidence derived from laboratory animal studies and clinical data, we postulate that androgen insufficiency disrupts cellular-signaling pathways and produces pathologic alterations in penile tissues, leading to erectile dysfunction. In this review, we discuss androgen-dependent cellular, molecular, and physiologic mechanisms modulating erectile function in the animal model, and the implication of this knowledge in testosterone use in the clinical setting to treat erectile dysfunction. The new clinical paradigm incorporates many of the consensed points of view discussed in traditional consensed algorithms exclusively designed for men with androgen insufficiency. There are, however, novel and innovative differences with this new clinical paradigm. This paradigm represents a fresh effort to provide mandatory and optional management strategies for men with both androgen insufficiency and erectile dysfunction.

CONCLUSIONS

The new clinical paradigm is evidence-based and represents one of the first attempts to address a logical management plan for men with concomitant hormonal and sexual health concerns.

Reduced fertility among overweight and obese men

BACKGROUND

Overweight and obese men have been reported to have lower sperm counts and hormonal changes, but data are lacking regarding effects on couple fertility.

METHODS

We examined the relationship between male body mass index (BMI) and infertility in couples enrolled in the Agricultural Health Study in the United States. The analysis sample was limited to couples (wife <40 years old) with an attempt at pregnancy in the last 4 years based on pregnancy and fertility data provided by wives. Infertility was defined as not conceiving a pregnancy after at least 12 months of unprotected intercourse regardless of whether or not a pregnancy ultimately occurred. Self-reported weight and height were used to calculate BMI (kg/m). Adjusted odds ratios (aORs) for infertility associated with increases in male BMI were calculated with logistic regression.

RESULTS

Adjusting for potential confounders, a 3-unit increase in male BMI was associated with infertility (aOR = 1.12; 95% confidence interval = 1.01-1.25; n = 1329). There was a dose-response relationship, and the BMI effect was stronger when the data were limited to couples with the highest-quality infertility data. The association between BMI and infertility was similar for older and younger men, suggesting that erectile dysfunction in older men does not explain the association.

CONCLUSIONS

This report of lower fertility in overweight and obese men needs replication. If the findings are robust, programs to prevent obesity may improve men's reproductive health and save medical costs for infertility treatment.

Obesity and sexual quality of life

OBJECTIVES

Reduced sexual quality of life is a frequently reported yet rarely studied consequence of obesity. The objectives of this study were to 1) examine the prevalence of sexual quality-of-life difficulties in obese individuals and 2) investigate the association between sexual quality of life and BMI class, sex, and obesity treatment-seeking status.

RESEARCH METHODS AND PROCEDURES

Subjects consisted of 1) 500 participants in an intensive residential program for weight loss and lifestyle modification (BMI = 41.3 kg/m2), 2) 372 patients evaluated for gastric bypass surgery (BMI = 47.1 kg/m2), and 3) 286 obese control subjects not seeking weight loss treatment (BMI = 43.6 kg/m2). Participants completed the Impact of Weight on Quality of Life-Lite, a measure of weight-related quality of life. Responses to the four Sexual Life items (assessing enjoyment, desire, performance, and avoidance) were analyzed by BMI, sex, and group.

RESULTS

Higher BMI was associated with greater impairments in sexual quality of life. Obese women reported more impairment in sexual quality of life than obese men for three of four items. Gastric bypass surgery candidates reported more impairment in sexual quality of life than residential patients and controls for most items. In general, residential patients reported levels of impairment greater than or equal to controls.

DISCUSSION

Obesity is associated with lack of enjoyment of sexual activity, lack of sexual desire, difficulties with sexual performance, and avoidance of sexual encounters. Sexual quality of life is most impaired for women, individuals with Class III obesity, and patients seeking gastric bypass surgery.

Effects of paradoxical sleep deprivation and cocaine on genital reflexes in hyperlipidic-fed rats

The present study was designed to investigate the effects of a hyperlipidic diet (HD) on penile erection (PE) and ejaculation (EJ) induced by cocaine in paradoxical sleep deprived (PSD) rats. Secondly, we aimed to verify the influence of HD cafeteria diet on steroid hormone levels. Twenty-one day-old male Wistar rats were randomly assigned into two groups: rats fed with commercial chow diet and rats fed with a palatable HD containing chow mixed with peanuts, milk chocolate and sweet cookies in the proportion of 3:2:2:1. After nine weeks of treatment, the animals were submitted to PSD or maintained as home cage control group for 96 h and challenged with cocaine (7 mg/kg, i.p.). Results showed that the HD led to a reduction in the frequency of erection in the PSD+cocaine group when compared to the PSD+cocaine fed with standard diet. Regardless of the diet, testosterone concentrations were significantly lower and progesterone was higher in the PSD rats than in the respective home-cage control rats. Although there were no hormonal alterations, the findings showed that a long-term HD might modify the stimulating effects of cocaine in potentiating genital reflexes in PSD rats.

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.

Changes in sex hormone-binding globulin and testosterone during weight loss and weight maintenance in abdominally obese men with the metabolic syndrome

BACKGROUND

Mild hypoandrogenism in men, usually defined by low levels of testosterone, is a peculiar feature of abdominal obesity that independently predicts the development of insulin resistance and diabetes mellitus. Little is known about the short- and long-term effects of weight loss on sex steroids in abdominally obese men, however.

OBJECTIVES

We assessed the effect of rapid weight loss and sustained weight maintenance on the plasma concentrations of testosterone and other sex hormones in 58 abdominally obese men (age, 46.3 +/- 7.5 years; body mass index, 36.1 +/- 3.8 kg/m(2); waist girth, 121 +/- 10 cm) with the metabolic syndrome.

RESULTS

The men lost on average 16.3 +/- 4.5 kg during a 9-week very low-calorie diet (VLCD) and maintained 14.3 +/- 9.1 kg weight loss after a 12-month maintenance period (vs. baseline, p < 0.001). Sex hormone-binding globulin (SHBG) increased from 27.6 +/- 11.9 to 48.1 +/- 23.5 nmol/l during the VLCD but decreased to 32.6 +/- 12.9 nmol/l during weight maintenance, which was still higher than at baseline (p < 0.001). Free testosterone (fT) increased from 185 +/- 66 to 208 +/- 70 pmol/l (p = 0.002) during the VLCD and remained high after 1 year of weight maintenance (212 +/- 84 pmol/l, p = 0.002). Total testosterone levels followed a pattern intermediate between fT and SHBG. Plasma estradiol and dehydroepiandrosterone sulphate concentrations changed only transiently or not at all.

CONCLUSIONS

Rapid weight loss with successful weight maintenance in abdominally obese men with the metabolic syndrome brings about a sustained increase in fT levels. The dramatic increase in SHBG attenuated initially during weight maintenance but remained elevated. These findings may be important with regard to prevention of progressive metabolic decompensation and cardiovascular disease associated with obesity and the metabolic syndrome.

Testosterone and sex hormone-binding globulin predict the metabolic syndrome and diabetes in middle-aged men

OBJECTIVE

In men, hypoandrogenism is associated with features of the metabolic syndrome, but the role of sex hormones in the pathogenesis of the metabolic syndrome and diabetes is not well understood. We assessed the association of low levels of testosterone and sex hormone-binding globulin (SHBG) with the development of the metabolic syndrome and diabetes in men.

RESEARCH DESIGN AND METHODS

Concentrations of SHBG and total and calculated free testosterone and factors related to insulin resistance were determined at baseline in 702 middle-aged Finnish men participating in a population-based cohort study. These men had neither diabetes nor the metabolic syndrome.

RESULTS

After 11 years of follow-up, 147 men had developed the metabolic syndrome (National Cholesterol Education Program criteria) and 57 men diabetes. Men with total testosterone, calculated free testosterone, and SHBG levels in the lower fourth had a severalfold increased risk of developing the metabolic syndrome (odds ratio [OR] 2.3, 95% CI 1.5-3.4; 1.7, 1.2-2.5; and 2.8, 1.9-4.1, respectively) and diabetes (2.3, 1.3-4.1; 1.7, 0.9-3.0; and 4.3, 2.4-7.7, respectively) after adjustment for age. Adjustment for potential confounders such as cardiovascular disease, smoking, alcohol intake, and socioeconomic status did not alter the associations. Factors related to insulin resistance attenuated the associations, but they remained significant, except for free testosterone.

CONCLUSIONS

Low total testosterone and SHBG levels independently predict development of the metabolic syndrome and diabetes in middle-aged men. Thus, hypoandrogenism is an early marker for disturbances in insulin and glucose metabolism that may progress to the metabolic syndrome or frank diabetes and may contribute to their pathogenesis.