Relation between plasma high-density lipoprotein cholesterol and sex hormone concentrations in men

The CATCH checklist to investigate adult-onset hypogonadism

Adult-onset hypogonadism is a syndrome often underdiagnosed, undertreated, or incompletely explored. There are various reasons for this: firstly, undefined age range of men in whom testosterone levels should be investigated and then no definitive serum cutoff point for the diagnosis of hypogonadism; and finally, variable and non-specific signs and symptoms; men and physicians do not pay adequate attention to sexual health. All these factors make the diagnostic criteria for hypogonadism controversial. The evaluation of the clinical features and causes of this syndrome, its link with age, the role of testosterone and other hormone levels, and the presence of any comorbidities are all useful factors in the investigation of this population. The purpose of this manuscript, after an accurate analysis of current literature, is to facilitate the diagnosis of hypogonadism in men through the use of the CATCH acronym and a checklist to offer a practical diagnostic tool for daily clinical practice. A narrative review of the relevant literature regarding the diagnosis of late-onset hypogonadism or adult-onset hypogonadism was performed. PubMed database was used to retrieve articles published on this topic. A useful new acronym CATCH (Clinical features [symptoms] and Causes, Age, Testosterone level, Comorbidities, and Hormones) and a practical checklist to facilitate the evaluation of hypogonadism in aging men were used. The evaluation of the clinical features and causes of hypogonadism, the link with age, the role of Testosterone and other hormones, and the evaluation of comorbidities are important in investigating adult-onset hypogonadism. The CATCH checklist could be helpful for clinicians for an early diagnosis of both hypogonadism and associated comorbidities. We suggest the use of this acronym to advocate the investigation of declining testosterone in aging men.

Hormonal, anthropometric and lipid factors associated with idiopathic pubertal gynecomastia

BACKGROUND AND OBJECTIVES

To determine factors associated with pubertal gynecomastia.

DESIGN AND SETTINGS

A cross-sectional study among healthy male school children and adolescents in Riyadh, Saudi Arabia.

METHODS

Subjects were selected from diverse socioeconomic backgrounds. Tanner stage, height, weight, blood hormonal levels (leutilizing hormone [LH], follicle-stimulating hormone [FSH], total testosterone, and estradiol), and anthropometric and lipid parameters (body mass index [BMI], triglycerides, high-density lipoprotein [HDL], and low-density lipoprotein [LDL]), were collected and compared in children with and without gynecomastia.

RESULTS

The study included 542 children and adolescents. Median (interquartile range) age in the whole group was 11(8-13) years. The prevalence of gynecomastia was 185/542 (34%), with a peak at age 14. The 2 groups compared had nonsignificant difference in cholesterol (P=.331), LH (P=.215) and FSH (P=.571) levels. Those with gynecomastia were significantly older, had lower gonad stage, had higher anthropometric (height, weight, and BMI), and lipid (triglycerides, HDL, and LDL) values. In multivariate regression analysis, factors significantly associated with gynecomastia were BMI (odds ratio [OR]=1.05; 95%CI 1.00-1.10; P=.013), HDL (OR=0.42; 95%CI 0.19-0.92; P=.03), and gonad (Stage II OR=2.23; 95%CI 1.27-3.92; P=.005, Stage III OR=6.40; 95%CI 2.70-15.0; P < .0001, Stage IV OR=3.24; 95%CI 1.32-7.95; P=.01, Stage V OR=1.37; 95%CI 0.52-3.56; P=.53, compared with stage I).

CONCLUSION

Pubertal gynecomastia tends to increase in mid-puberty. In our setting, BMI, HDL, and gonad stage were the major factors associated with the development of pubertal gynecomastia.

Association of serum testosterone with lipid abnormalities in patients with angiographically proven coronary artery disease

CONTEXT

Low testosterone levels are associated with an atherogenic lipid profile and may contribute to the pathogenesis of atherosclerosis.

AIMS

Our study aimed to investigate the relationship between serum total testosterone (TT) levels and lipid profile in angiographically confirmed coronary artery disease (CAD) in men.

SETTINGS AND DESIGN

This is a case-control hospital-based study at Teaching Hospital, Karapitiya, Galle, Sri Lanka.

MATERIALS AND METHODS

Two hundred and six men, 103 with angiographically proven CAD and 103 healthy men as a control group were studied. The serum levels of TT and lipids were assessed.

STATISTICAL ANALYSIS

Data were analyzed using Minitab software (version 15 for Windows).

RESULTS

THE MEAN CONCENTRATIONS OF LIPID PARAMETERS OF PATIENTS AND CONTROLS WERE AS FOLLOWS: Serum total cholesterol (TCh), 5.9 ± 2.8 vs. 5.2 ± 1.6 mmol/l (P = 0.022), low-density lipoprotein cholesterol (LDL-Ch), 3.9 ± 1.2 vs. 3.1 ± 0.5 mmol/l (P = 0.001), high-density lipoprotein cholesterol (HDL-Ch), 1.1 ± 0.5 vs. 1.4 ± 0.6 mmol/l (P = 0.001), and TGs, 2.0 ± 1.0 vs. 1.5 ± 0.8 mmol/l (P = 0.001); lipid levels were significantly different between the two groups. The mean levels of TT in the patients and controls were 11.4 ± 2.7 vs. 18.1 ± 7.2 nmol/l (P = 0.001), significantly different. Among CAD patients, a significant positive association was found between testosterone and HDL-Ch (r = 0.623, P = 0.001), whereas a negative association was found with LDL-Ch (r = -0.579, P = 0.001).

CONCLUSIONS

Low levels of TT in men with CAD that appear together with an atherogenic lipid milieu may be involved in the pathogenesis of CAD. The observed association between testosterone and HDL-Ch suggests a protective effect of the hormone.

Physiological levels of estradiol correlate with lipid / lipoprotein profiles in healthy men

In this cross-sectional study, the relationships of the physiological levels of estradiol (E2) and dehydroepiandrosterone-sulfate (DHEA-S) to the lipid and lipoprotein profiles were investigated in 212 apparently healthy men aged from 18 to 59 years old. These subjects were divided into tertiles according to the levels of E2 and DHEA-S, respectively. We performed one-way analysis of variance and analysis of co-variance controlling for age, body mass index, percent body fat, waist to hip ratio, maximal oxygen uptake, alcohol and cigarette consumptions as confounding factors.A lower E2 level was associated with higher concentrations of total cholesterol (TC) and low density lipoprotein cholesterol. A lower DHEA-S level was associated with a lower concentration of high density lipoprotein cholesterol (HDLC) and a higher ratio of TC / HDLC. These correlations remained significant after adjusting for the above confounding factors. Neither free testosterone nor sex hormone-binding globulin was associated with the lipids and lipoproteins. These results suggest that higher levels of E2 and DHEA-S, at least in physiological concentrations, are related to the favorable lipid and lipoprotein levels in men.

Hormone replacement therapy and physical function in healthy older men. Time to talk hormones?

Improving physical function and mobility in a continuously expanding elderly population emerges as a high priority of medicine today. Muscle mass, strength/power, and maximal exercise capacity are major determinants of physical function, and all decline with aging. This contributes to the incidence of frailty and disability observed in older men. Furthermore, it facilitates the accumulation of body fat and development of insulin resistance. Muscle adaptation to exercise is strongly influenced by anabolic endocrine hormones and local load-sensitive autocrine/paracrine growth factors. GH, IGF-I, and testosterone (T) are directly involved in muscle adaptation to exercise because they promote muscle protein synthesis, whereas T and locally expressed IGF-I have been reported to activate muscle stem cells. Although exercise programs improve physical function, in the long-term most older men fail to comply. The GH/IGF-I axis and T levels decline markedly with aging, whereas accumulating evidence supports their indispensable role in maintaining physical function integrity. Several studies have reported that the administration of T improves lean body mass and maximal voluntary strength in healthy older men. On the other hand, most studies have shown that administration of GH alone failed to improve muscle strength despite amelioration of the detrimental somatic changes of aging. Both GH and T are anabolic agents that promote muscle protein synthesis and hypertrophy but work through separate mechanisms, and the combined administration of GH and T, albeit in only a few studies, has resulted in greater efficacy than either hormone alone. Although it is clear that this combined approach is effective, this review concludes that further studies are needed to assess the long-term efficacy and safety of combined hormone replacement therapy in older men before the medical rationale of prescribing hormone replacement therapy for combating the sarcopenia of aging can be established.

Testosterone and cardiovascular disease in men

Despite regional variations in the prevalence of coronary artery disease (CAD), men are consistently more at risk of developing and dying from CAD than women, and the gender-specific effects of sex hormones are implicated in this inequality. This 'Perspectives' article reviews the current evidence regarding the cardiovascular effects of testosterone in men including an examination of the age-related decline in testosterone, the relationship between testosterone levels and coronary disease, coronary risk factors and mortality. We also review the vaso-active effects of testosterone, and discuss how these have been used in men with heart failure and angina. We discuss the 'cause' versus 'effect' controversy, regarding low testosterone levels in men with coronary heart disease, as well as concerns over the use of testosterone replacement therapy in middle aged and elderly men. The article concludes with a discussion regarding the future direction for work in this interesting area, including the relative merits of screening for, and treating hypogonadism with testosterone replacement therapy in men with heart disease.

Inverse association between total testosterone concentrations, incident hypertension and blood pressure

BACKGROUND

Studies on the relationship between testosterone concentrations and blood pressure have yielded inconsistent results. Therefore, this study investigated the prospective association of total testosterone (TT) concentrations with risk of incident hypertension and blood pressure change in 1,484 men aged 20-79 years.

METHODS

Data from the population-based Study of Health in Pomerania, Germany, were used. Serum TT concentrations, measured by chemiluminescent enzyme immunoassays, were categorised into age-specific quartiles. Generalised Estimating Equation (GEE) models, adjusted for age, waist circumference, physical activity, smoking and alcohol consumption were specified.

RESULTS

During a median follow-up time of 5.0 years, the prevalence of hypertension increased from 50.6% to 57.1%. TT concentrations were significantly lower in men with baseline and incident hypertension. Analyses revealed that men with baseline TT concentrations in the lowest quartile had an increased risk of incident hypertension (odds ratio (OR), 1.19 (95% CI, 1.10-1.28)) compared to men with higher TT concentrations. Furthermore, we found a significant inverse association of TT concentrations and blood pressure, showing that men with baseline TT concentrations in the lowest quartile showed the slightest change in systolic blood pressure (-6.01 mmHg), diastolic blood pressure (-2.11 mmHg) and pulse pressure (-3.98 mmHg). Sensitivity analyses in a subpopulation of men without antihypertensive medication confirmed these findings.

CONCLUSION

These results show that low male TT concentrations are predictive of hypertension, suggesting TT as a potential biomarker of increased cardiovascular risk.

Testosterone and coronary artery disease

Cardiovascular disease remains the leading cause of death in most of the developed world despite advances in both prevention and treatment. At the same time, the incidence rates of cardiovascular disease differ greatly between the genders, with men more likely than women to manifest ischemic heart disease. This observation has prompted new research initiatives to explain the discrepancy in heart disease prevalence and incidence between the sexes. Whether androgens affect cardiovascular disease adversely remains a contentious issue, with some data pointing to a deleterious effect of androgens on lipid profiles, and other studies revealing androgens' possible benefits on cardiovascular function. This review will examine the relationship between the endogenous production of androgen as well as the exogenous replacement of testosterone in men and the possible links to cardiovascular disease. The role of testosterone in male cardiovascular health is not completely understood, and additional studies are needed to explain its effect on atherosclerosis and its complications.

Association of serum cholesterol and cholesterol-lowering drug use with serum sex steroid hormones in men in NHANES III

PURPOSE

Low cholesterol levels and statin drugs may protect against prostate cancer with a worse prognosis. Their protective mechanism is unknown, but has been hypothesized to be related to cholesterol's role as a sex steroid hormone precursor. We evaluated whether serum testosterone and estradiol differ by cholesterol or cholesterol-lowering drug use.

MATERIALS AND METHODS

Testosterone and estradiol were measured for 1,457 male participants in the Third National Health and Nutrition Examination Survey. We estimated multivariable-adjusted geometric mean hormone concentration by quintiles of cholesterol concentration and by cholesterol-lowering drugs use.

RESULTS

Across quintiles of cholesterol, testosterone level did not differ (mean, 95% confidence interval (CI); Q1: 5.25, 5.02-5.49, Q5: 5.05, 4.76-5.37 ng/ml; p-trend = 0.32), whereas estradiol levels were lower (Q1: 38.7, 36.9-40.5; Q5: 33.1, 31.8-34.5 pg/ml; p-trend < 0.0001). Neither testosterone (no: 5.12, 4.94-5.30, yes: 4.91, 4.33-5.57 ng/ml, p = 0.57) nor estradiol (no: 35.9, 34.8-37.1; yes: 33.9, 29.4-39.2 pg/ml; p = 0.39) differed by cholesterol-lowering drugs use.

CONCLUSION

Testosterone did not differ by cholesterol or cholesterol-lowering drug use. Estradiol was lower in men with higher cholesterol, but did not differ by cholesterol-lowering drug use. Our results suggest that the lower risk of advanced prostate cancer among statin users is not readily explained by a cholesterol-mediated effect of statins on sex hormone levels.

Cardiovascular disease and androgens: a review

Globally, cardiovascular disease is the single largest cause of mortality. The differences in pattern of cardiovascular disease between the two genders have not been explained properly. The spotlight has largely been focused on estrogens but no conclusive evidence has proven its role in reducing the incidence of cardiovascular disease. Consequently, androgens have attracted significant interest in explaining the gender difference in cardiovascular disease. More studies in last two decades have increased our knowledge about the effects of androgens on cardiovascular disease progression. Evidence for age related fall in testosterone levels in males and increasing cardiovascular events with age had lead to the postulation of idea of 'andropause or male menopause'. Unfortunately, for the last few decades the androgens have been highlighted as agents of abuse among athletes all over the world. There have been multiple reports of their association with sudden cardiac death and adverse cardiovascular outcomes when abused. Contrastingly, there has been an increasing prescription use of testosterone supplementation in various conditions related to androgen deficiency state and for many other off-label indications. Human observational studies have mostly concluded that men with lower testosterone levels tend to have higher incidence of coronary artery disease. Emerging evidence supports that lower androgen levels predict poor cardiovascular risk profile. Role with supplementation of testosterone for cardiovascular disease is being studied in both primary and secondary prevention stages and its safety being evaluated. This is an appropriate time to review the role of androgens specifically from a cardiovascular standpoint.

Androgen deficiency as a predictor of metabolic syndrome in aging men: an opportunity for intervention?

The prevalence of metabolic syndrome is increasing globally and is an important risk factor for the development of cardiovascular disease. Longitudinal population studies have found that low testosterone status in men is a risk factor for the later development of metabolic syndrome. Men with metabolic syndrome and type 2 diabetes mellitus have a higher incidence of hypotestosteronaemia. Furthermore, in men, testosterone levels are inversely associated with the degree of carotid and aortic atherosclerosis. Early interventional, short-term studies have shown that testosterone replacement therapy has a beneficial effect on visceral obesity, insulin sensitivity, glycaemic control and lipid profiles in men with diagnosed hypogonadism with and without diabetes. The effect of testosterone therapy on atherogenesis in men is unknown; however, animal studies have shown that testosterone is atheroprotective and can ameliorate the degree of atherosclerosis. Testosterone is an arterial vasodilator and has been shown to improve myocardial ischaemia in men with coronary artery disease. This review discusses the role that testosterone may play in the pathogenesis of metabolic syndrome in men and also examines the potential role of testosterone replacement therapy in this condition.

Pubertal progression and serum lipid profile in obese children

BACKGROUND

During puberty, sex hormones are associated with decrease in serum lipids in healthy individuals.

AIM

To investigate the relationships between pubertal development, serum lipid profile and atherogenic indices in obese children and adolescents.

METHODS

Body mass index (BMI), blood pressure, and serum lipids of 340 obese children (182 girls, 158 boys) aged 3.6-17.8 years were measured. Atherogenic index, total cholesterol (TC)/high-density lipoprotein-cholesterol (HDL-C) and low-density lipoprotein-cholesterol (LDL-C)/HDL-C were calculated as indices of atherogenic risk.

RESULTS

Weight (F = 62.078; p < 0.001), BMI (F = 21.083; p < 0.001), systolic blood pressure (SBP) (F = 11.956; p < 0.001) and diastolic blood pressure (DBP) (F = 3.947, p = 0.005) differed significantly between pubertal stages and increased with advance in stages in males. HDL-C (F = 4.586; p = 0.004) differed significantly between pubertal stages and decreased with advancing stages in males. Weight (F = 66.915; p <0.001), BMI (F = 23.101; p <0.001), SBP (F = 10.873; p <0.001), DBP (F = 2.839; p = 0.040) and LDL-C (F = 3.072; p = 0.029) differed significantly between pubertal stages and increased with advancing stages in girls. Triglyceride, TC, LDL-C and SBP were statistically significant determinants for HDL-C according to multivariate linear regression analysis. SBP was significantly affected by chronological age, BMI, glucose, TC and HDL-C according to stepwise linear regression analysis.

CONCLUSION

The increasing rate of obesity is associated with an increase in cardiovascular risk factors in parallel with advance in pubertal stages, particularly in boys.

Acute effect of smoking on gallbladder emptying and refilling in chronic smokers and nonsmokers: A sonographic study

AIM: To ultrasonographicaly evaluate the acute effects of smoking on gallbladder contraction and refilling in chronic smokers and nonsmokers.

METHODS: Fifteen chronic smokers (21-30 years old) and fifteen nonsmokers (21-35 years old) participated in this study. Chronic smokers were selected among the volunteers who had been smoking for at least 5 years and 10 cigarettes per day (mean 17.5/d). Examinations were performed in two separate days. In the first day, basal gallbladder (GB) volumes of volunteers were measured after 8-h fasting. After the examinations, participants had a meal containing at least 30-40 gram fat. Gallbladder volume was assessed at 5, 15, 30, 60, 120 and 180 min after the meal. In the second day, participants smoked 2 cigarettes after 8-h fasting. Then, they had the same meal, and gallbladder measurements were repeated at the same time points. Same procedures were applied to both groups.

RESULTS: The mean starving GB volumes were 23.3 ± 3.3 mL in the first day, 21.9 ± 3.0 mL in the second day in nonsmoker group and 18.3 ± 3.0 mL in the first day, 19.5 ± 2.8 mL in second day in smoker group. There was no significant difference between starving GB volumes. We did not find any significant difference between the GB volumes measured at 5, 15, 30, 60, 120 and 180 min in the first and second days in nonsmoker group. In smokers, post cigarette GB volume was found significantly higher at 5, 15 and 30 min which corresponded to GB contraction phase (P < 0.05). Control GB volume measurements were not significantly different between the two groups. Post-smoking GB volumes were also not significantly different between the two groups.

CONCLUSION: Smoking prolongs the maximal GB emptying time both in smokers and in nonsmokers though it is not significant. It delays GB contraction in chronic smokers and causes a significant decrease in GB emptying volume. Smoking causes no significant delay in GB refilling in both smokers and nonsmokers. These effects of smoking observed in acute phase result in bile stasis in GB. Bile stasis is the underlying cause of most GB disorders in chronic process.

Epidemiology: testosterone and the metabolic syndrome

Low levels of testosterone, hypogonadism, have several common features with the metabolic syndrome. In the Tromsø Study, a population-based health survey, testosterone levels were inversely associated with anthropometrical measurements, and the lowest levels of total and free testosterone were found in men with the most pronounced central obesity. Total testosterone was inversely associated with systolic blood pressure, and men with hypertension had lower levels of both total and free testosterone. Furthermore, men with diabetes had lower testosterone levels compared to men without a history of diabetes, and an inverse association between testosterone levels and glycosylated hemoglobin was found. Thus, there are strong associations between low levels of testosterone and the different components of the metabolic syndrome. In addition, an independent association between low testosterone levels and the metabolic syndrome itself has recently been presented in both cross-sectional and prospective population-based studies. Thus, testosterone may have a protective role in the development of metabolic syndrome and subsequent diabetes mellitus and cardiovascular disease in aging men. However, clinical trials are needed to confirm this assumption.

The aging male: testosterone deficiency and testosterone replacement. An up-date

The significance of the age-related decline of androgens remains unclear in terms of cardiovascular risk, mood and cognition, and prostatic health. Although much research has been undertaken in this area and men's health has received still more attention in the latest years, there are no data based on randomized controlled clinical studies in aging men investigating the long-term effects of androgen replacement therapy on various aspects of the cardiovascular system, the immune system, body composition, and the brain. In men receiving long-term androgen replacement therapy, the safety aspects regarding the prostate are also an area of clinical importance. In this paper we present an up-dated review of the experimental and clinical evidence of androgen deficiency and androgen replacement therapy on carbohydrate metabolism, on coagulation and fibrinolysis, inflammatory effects, effects on lipoprotein metabolism, direct arterial effects, effects on body composition, effects on cognitive function and mood, and prostatic effects. The evidence clearly shows that data for the most part are conflicting, with only very few randomized studies available.

Influence of sex and diet on quantitative trait loci for HDL cholesterol levels in an SM/J by NZB/BlNJ intercross population

To investigate the dependence of HDL quantitative trait loci (QTL) on sex and diet, we generated a large intercross population of mice from parental strains SM/J and NZB/BlNJ. We measured HDL levels in progeny fed a chow diet and measured them again after 6, 12, and 16 weeks of feeding a high-fat, high-cholesterol diet. QTL analysis was performed on the 260 female and 253 male F(2) progeny. A total of 13 significant QTL were found. Four QTL were specific to female mice: Hdlq23 (Chr 6, 26 cM), Hdlq26 (Chr 10, 70 cM), Hdlq27 (Chr 15, 48 cM), and Hdlq32 (Chr 19, 40 cM). One significant QTL was specific to male mice: Hdlq29 (Chr 17, 36 cM). In addition, several QTL were found to have effects that were dependent on diet. Sex- and diet-dependent effects were characterized using a linear model-based genome scan method that avoids the potential pitfalls of subdivided data analysis. The dependence of QTL effects on sex suggests an important role for the sex hormones in HDL regulation. We recommend that sex should be explicitly accounted for in future studies in the genetics of HDL regulation in both mice and humans.

Endogenous sex hormones and cardiovascular disease in men

Unlike women, men do not experience an abrupt reduction in endogenous sex hormone production. It has, however, become clear that an age-associated decrease in the levels of (bioactive) sex hormones does occur. Whether endogenous sex hormones have an impact on cardiovascular disease has for many years remained largely unknown, but during the last decade more attention has been drawn to the importance of testosterone, estrogens, and adrenal androgens in etiology, prevention, and treatment of male cardiovascular disease. The purpose of this article is to summarize the evidence currently available on the association between endogenous sex hormones and cardiovascular disease in males. Published studies dealing with the relationship between circulating levels of sex hormones and cardiovascular disease in males were reviewed. The studies reviewed in this article suggest that circulating endogenous sex hormones and estrogens have a neutral or beneficial effect on cardiovascular disease in men.

Differential contribution of testosterone and estradiol in the determination of cholesterol and lipoprotein profile in healthy middle-aged men

The role of endogenous sex steroids in the association between male gender and cardiovascular risk remains unclear. We performed a cross-sectional analysis of the role of endogenous testosterone (T) and estradiol (E2), as well as their respective biologically active fractions, in the determination of lipids and lipoproteins in an occupation-based cohort of 715 healthy middle-aged men. Serum T, sex hormone binding globulin (SHBG) and E(2) were measured by immunoassays; free T (FT) and free E2 (FE2) were calculated using a validated equation. Serum total cholesterol (Chol), HDL-cholesterol (HDL-Chol), apolipoproteins A1 (ApoA1), B (ApoB), E (ApoE), ApoE phenotype, lipoprotein a (Lpa), fibrinogen, C-reactive protein (CRP), systolic (SBP) and diastolic blood pressure (DBP) were assessed. Serum levels of T and FT, correlated positively with HDL-Chol and ApoA1 with Spearman correlation coefficients, partialised for age and body mass index (BMI), ranging between 0.14 and 0.17 (P<0.001); FT was associated with total Chol and ApoB levels (r=0.12 for both T and FT; P<0.01). After adjustment for age and BMI, both serum E2 and FE2 levels correlated significantly with ApoE (r=0.25 and r=0.26 for E2 and FE2, respectively; P<0.001). Free and total E2 were associated with both SBP and DBP with correlation coefficients partialised for age and BMI ranging between 0.11 and 0.13 (P<0.01). No correlation was found between any of the studied sex steroids, fibrinogen, Lpa or CRP. In multiple linear regression analyses, T was the most important independent hormonal determinant of HDL-Chol levels, when E2, SHBG and exogenous factors were considered in the model (P<0.01), whereas E2 contributed mostly in the determination of ApoE levels (P<0.001) and SBP (P<0.01). When FT and FE2 were considered in multivariate analyses as independent hormonal variables, FT was the most significant predictor of HDL-Chol (P<0.01) and ApoB (P<0.01) concentrations. Moreover, in the same multivariate model, ApoE (P<0.001) concentration as well as SBP (P<0.001) was most affected by FE2 levels in comparison with FT. In conclusion, our findings do suggest a differential role of T and E2 in the determination of traditional cardiovascular risk factors in healthy middle-aged men. In the determination of both HDL-Chol and ApoB levels endogenous (F)T may be involved, whereas (F)E2 may contribute to the determination of ApoE levels in this study group of 715 healthy middle-aged men. Regarding the observational design of the study, the physiological relationship of the observed associations between sex steroids and cardiovascular risk factors remains to be unravelled.

Intramuscular testosterone esters and plasma lipids in hypogonadal men: a meta-analysis

PURPOSE

It is unclear whether intramuscular administration of testosterone esters to hypogonadal men is associated with changes in plasma lipids. We therefore analyzed 19 studies published between 1987 and 1999 that focused on male subjects with nonexperimental hypogonadism, treated subjects with an intramuscular testosterone ester and reported pretreatment and post-treatment concentrations of total cholesterol, low-density lipoprotein (LDL), high-density lipoprotein (HDL) cholesterol, or total triglyceride.

METHODS

We calculated study-specific, post-treatment minus pretreatment differences in each plasma lipid concentration (mean [95% confidence interval]). After testing of between-study homogeneity, we combined the study-specific differences. We then determined whether heterogeneity of differences could be explained in models of the differences on study and patient characteristics (mean +/- SE) before and after excluding extreme values using a multiple outlier procedure.

RESULTS

The studies represented 272 hypogonadal men (age 44 +/- 4 years; 20% with hypergonadotropic hypogonadism; total testosterone 0.5 +/- 0.2 ng/mL) who received, on average, 179 +/- 13 mg intramuscular testosterone ester every 16 +/- 1 days for 6 +/- 1 months. Fixed-effects estimates of post-treatment minus pretreatment differences were -14 [-17 to -11] mg/dL (total cholesterol), -5 [-8 to -1] mg/dL (LDL cholesterol), -4 [-5 to -2] mg/dL (HDL cholesterol), and -1 [-6 to + 4] mg/dL (triglyceride). Decreases in HDL cholesterol were larger at lower dosages of testosterone ester (r = -0.54, P = 0.055), but were not explained by attrition, regression to the mean, dosing frequency or duration, concomitant elevation of plasma total testosterone, aromatization of testosterone to estradiol, or other study and patient characteristics.

CONCLUSION

Intramuscular administration of testosterone esters to hypogonadal men is associated with a small, dosage-dependent decrease in HDL cholesterol and concomitant declines in total cholesterol and LDL cholesterol. The aggregate effect of these changes on cardiovascular risk remains unknown but deserves further study.

Mapping of microsatellite loci and association of aorta atherosclerosis with LG VI markers in the rabbit

Twenty-three rabbit microsatellites were extracted from the EMBL nucleotide database. Nine of these markers, together with nine earlier published microsatellite markers, were found to be polymorphic between the AX/JU and IIIVO/JU inbred strains. By using an F(2) intercross we could integrate five markers into the rabbit linkage map. One anonymous microsatellite marker could be assigned to chromosome 1, and one microsatellite marker, located within the metallothionein-1 gene, could be added to linkage group VI (LG VI). Three microsatellite markers (one anonymous, one located within the PMP2 gene, and one located within the FABP6 gene) constitute a new linkage group (LG XI). We also measured the degree of dietary cholesterol-induced aorta atherosclerosis in the F(2) animals. A significant cosegregation was found between the degree of aorta atherosclerosis and the allelic variation of the biochemical marker Est-2 on LG VI in male rabbits. This association was not found in female rabbits.

Effect of testosterone replacement therapy on lipids and lipoproteins in hypogonadal and elderly men

We investigated the effects of long-term testosterone replacement in hypogonadal and elderly men on lipids and lipoproteins. Twenty-two men with initial serum testosterone concentrations below 3.5 ng/ml took part in the study: 11 with hypopituitarism (1st group) and 11 otherwise healthy elderly men with low testosterone levels (2nd group). Testosterone deficiency was replaced by intramuscular injections of testosterone enanthate 200 mg every second week. Plasma levels of sex hormones, gonadotropins, SHBG, lipids and lipoproteins were determined before the treatment and after 3, 6 and 12 months of treatment. During the treatment serum testosterone and estradiol increased significantly, reaching normal levels. This was associated with a decrease in total cholesterol (from 225 +/- 16.9 mg/dl to 202 +/- 13.6 mg/dl after 6 months and 198 +/- 12.8 mg/dl after 1 year of testosterone administration, P < 0.0001 in men with hypoandrogenism associated with aging and from 255 +/- 12.1 mg/dl to 214 +/- 10.6 mg/dl after 6 months and 206 +/- 9 mg/dl after 1 year of treatment, P < 0.0001 in men with hypopituitarism) and LDL-cholesterol concentrations (from 139 +/- 12.5 mg/dl to 126 +/- 10.7 mg/dl after 6 months and 118 +/- 9.8 mg/dl after 1 year of testosterone administration, P < 0.0001 in men with hypoandrogenism associated with aging and from 178 +/- 10.3 mg/dl to 149 +/- 10.2 mg/dl after 6 months and 140 +/- 7.3 mg/dl after 1 year of treatment, P < 0.001 in men with hypopituitarism). However, no significant decrease in HDL-cholesterol levels or HDL2- and HDL3-cholesterol subfractions was observed. The effects of testosterone replacement therapy on lipids and lipoproteins were similar in both groups with different aetiology of hypogonadism. No side effects on the prostate were observed. The results of this study indicate that testosterone replacement therapy in hypogonadal and elderly men may have a beneficial effect on lipid metabolism through decreasing total cholesterol and atherogenic fraction of LDL-cholesterol without significant alterations in HDL-cholesterol levels or its subfractions HDL2-C and HDL3-C.

The relationships of testosterone, estradiol, dehydroepiandrosterone-sulfate and sex hormone-binding globulin to lipid and glucose metabolism in healthy men

We investigated the relationships of plasma sex hormones (free testosterone; free T, estradiol; E2 dehydroepiandrosterone-sulfate; DHEA-S) and sex hormone-binding globulin (SHBG) levels to lipid and glucose metabolism cross-sectionally in 212 apparently healthy men aged from 18 to 59 years. A multiple linear regression analysis for lipid and glucose parameters with age, body mass index (BMI), percent body fat (%fat), waist to hip ratio (WHR), estimated maximal oxygen uptake (VO2max), alcohol and cigarette consumption, sex hormones, and SHBG, respectively, as independent variables, was performed. DHEA-S was indicated as one of the independent predictors of both high density lipoprotein cholesterol (HDL-C), with a positive relation, and of triglyceride and total cholesterol/HDL-C ratio, with a negative relation, while SHBG was one of the predictors of both HDL-C, with a positive relation, and of fasting insulin, with a negative relation. The E2 level was found to be negatively related to both low density lipoprotein cholesterol and fasting blood glucose. These findings thus suggest that the higher levels of SHBG, DHEA-S and E2 within physiological ranges in healthy men may partially help to maintain a desirable profile of the plasma lipid and glucose metabolism.

Effects of androgens on coronary artery atherosclerosis and atherosclerosis-related impairment of vascular responsiveness

The factors responsible for the marked gender differences in risk of coronary heart disease and atherosclerosis severity remain largely undetermined. While some clinical and experimental evidence supports a protective effect of endogenous estrogen on the initiation and progression of atherosclerosis and incidence of coronary heart disease, much of the epidemiological data do not support this conclusion. The possibility that endogenous androgens may have adverse effects on atherosclerosis progression and coronary risk has received little attention. We investigated the effects of experimentally induced hyperandrogenism in female cynomolgus monkeys with diet-induced atherosclerosis. Animals were assigned randomly to one of four treatment groups: (1) untreated controls, (2) ovariectomized (sex hormone-deficient) controls, (3) treated with androstenedione and estrone (mild hyperandrogenism), or (4) treated with testosterone (male plasma androgen pattern). At necropsy, coronary atherosclerosis was approximately twice as extensive (P < .05) in testosterone-treated animals relative to untreated controls, while treatment with androstenedione and estrone had no effect on atherosclerosis extent. Coronary plaque size was positively correlated with lumen size in intact and ovariectomized controls; however, there was no evidence of a similar relation between animals in either androgen treatment group. The atherogenic effects of testosterone were independent of variations in plasma lipoprotein and nonlipoprotein risk variables. Although chronic hyperandrogenism had adverse effects on atherosclerosis progression, it reversed (P < .03) atherosclerosis-related impairment of endothelium-dependent vasodilator responses. We conclude that an experimentally induced male plasma androgen pattern results in exacerbation of diet-induced atherosclerosis-related arterial remodeling in female monkeys.(ABSTRACT TRUNCATED AT 250 WORDS)

Endogenous sex hormones: impact on lipids, lipoproteins, and insulin

Estrogen use has been reported to decrease triglyceride and low-density lipoprotein cholesterol (LDL-C) and increase high-density lipoprotein cholesterol (HDL-C). Estrogen use increases the secretion of large, very low-density lipoprotein cholesterol (VLDL-C) and also stimulates the uptake of VLDL-C by the liver and increases the catabolism of LDL-C in the liver. Sex hormones may affect several enzymes involved in the metabolism of HDL-C and triglyceride and may also affect lipolysis. In both pre- and postmenopausal women, several studies have shown that increased glucose and insulin concentrations are associated with increased free testosterone and decreased sex hormone binding globulin. The temporal direction of this relationship in premenopausal women is not clear, however. In contrast to women, increased androgen concentrations in men do not seem to be associated with increased cardiovascular risk factors, although testosterone concentrations are associated with increased HDL-C and decreased insulin concentrations. Dehydroepiandrosterone (DHEA) and dehydroepiandrosterone sulfate (DHEAS) appear to be associated with improved cardiovascular risk factors in men, but this connection in women is less clear.

Transdermal dihydrotestosterone treatment of 'andropause'

Male ageing coincides on average with progressive impairment of testicular function. The most striking plasma changes are an increase in sex hormone binding globulin (SHBG) and a decrease in non SHBG-bound testosterone, which is the only testosterone subfraction effectively bioavailable for target tissues. In healthy subjects the bioavailable testosterone declines by approximately 1% per year between 40 and 70 years but a more pronounced decline has been observed in non-healthy groups, especially in high cardiovascular risks groups. Relative androgen deficiency is likely to have unfavourable consequences on muscle, adipose tissue, bone, haematopoiesis, fibrinolysis, insulin sensitivity, central nervous system, mood and sexual function and might be treated by an appropriate androgen supplementation. The potential risk for prostate has been the main reason for limiting indications of such treatment. Testosterone (T) and dihydrotestosterone (DHT) are two potent androgens which have opposite effects regarding aromatase activity, an enzyme present in prostate stroma and suspected to have a pathogenic influence through local oestradiol synthesis. T is the main substrate for aromatase and oestradiol synthesis while DHT is not aromatizable and, at sufficient concentration, decreases T and oestradiol levels. A 1.8 years survey of 37 men aged 55-70 years treated with daily percutaneous DHT treatment suggested that high plasma levels of DHT (> 8.5 nmol/l) effectively induced clinical benefits while slightly but significantly reducing prostate size. Early stages of prostate hypertrophy require synergic stimulation by both DHT and oestradiol, and suppressing oestradiol instead of DHT seems easier and better adapted to the specific situation of aged hypogonadic men.(ABSTRACT TRUNCATED AT 250 WORDS)

Interrelation between plasma testosterone and plasma insulin in healthy adult men: the Telecom Study

Plasma insulin is a risk factor for diabetes mellitus and cardiovascular disease in men. We investigated the association between plasma testosterone and plasma insulin in an occupational sample of 1292 healthy adult men. Total plasma testosterone decreased with each decade of age and insulin increased with each decade of age. In these cross-sectional data, this significant graded inverse association between testosterone and insulin was independent of age. The association was reduced but not explained by the addition of obesity and subscapular skinfold to the model. Adjustment for alcohol consumption, cigarette smoking and plasma glucose did not materially alter the association. These results are the reverse of the positive association of androgens with insulin in women and suggest alternative possible explanations for the effect of hyperinsulinaemia on cardiovascular disease risk. Prospective studies will be necessary to determine the direction and causal nature of this association.

Sex hormone concentrations in men with angiographically assessed coronary artery disease--relationship to obesity and body fat distribution

The relationship between circulating sex hormone levels and the occurrence of coronary artery disease (CAD) was studied in a group of 274 men undergoing coronary angiography. Hormone levels in men with CAD (n = 200) were compared to those in men found to be free of coronary lesions (n = 74). No significant differences were found for serum concentrations of estradiol, total testosterone, sex-hormone-binding globulin, free androgen index, dehydroepiandrosterone sulfate, or cortisol between the two groups. Serum androgens were negatively correlated to age in both groups, whereas estradiol was weakly associated with total cholesterol in the group of men without CAD. No consistent associations were detected between sex hormone levels and the degree of obesity or the distribution of body fat, the latter being assessed by the ratio of waist-to-hip circumferences. The results of this study do not support a significant role of sex steroid hormones in coronary artery disease in men.

Association between baseline risk factors, cigarette smoking, and CHD mortality after 10.5 years. MRFIT Research Group

METHODS

The association between baseline risk factors and death from coronary heart disease (CHD) after 10.5 years was investigated for cigarette smokers and nonsmokers who entered the Multiple Risk Factor Intervention Trial (MRFIT).

RESULTS

Rates per thousand person-years of CHD mortality were higher for smokers than for nonsmokers at every level of baseline risk factors examined. There were significant associations between CHD mortality and plasma low-density lipoprotein and high-density lipoprotein cholesterol for smokers and nonsmokers. The inverse association between CHD mortality and high-density lipoprotein cholesterol was significantly stronger among nonsmokers compared with that among smokers and was attributable to a very strong association for former smokers. An inverse relationship between CHD and body mass index was evident for smokers and nonsmokers. Rates of CHD death rose sharply when levels of fasting glucose exceeded 140 mg/dl, and there was a significant association between CHD mortality and blood sugar levels for nonsmokers but not for smokers. For both smokers and nonsmokers, an inverse univariate association between alcohol consumption and CHD mortality was evident. This association, however, did not persist after adjustment for plasma high-density lipoprotein cholesterol.

CONCLUSION

Intervention on blood pressure and blood lipids is particularly important among cigarette smokers because of their increased risk of CHD death. The different associations between high-density lipoprotein cholesterol, fasting serum glucose, and CHD mortality for smokers and nonsmokers requires further investigation.

Endogenous sex hormones, high density lipoprotein cholesterol, and other lipoprotein fractions in men

At least some of the large preponderance for coronary heart disease in men has been attributed to differences in lipid and lipoprotein levels; notably, high density lipoprotein cholesterol (HDL-C), a protective factor, is higher in women. The sex differences in lipid levels have been postulated to be related to differences in sex hormones. In a southern California cohort of 391 men aged 30-79 years, HDL-C levels were positively correlated and very low density lipoprotein cholesterol (VLDL-C) levels were inversely correlated with testosterone levels independently of age, body mass index, physical exercise, smoking, and alcohol intake. Mean HDL-C levels were 12% higher and VLDL-C levels were 40% lower in the highest compared with the lowest quartile of testosterone level. Low density lipoprotein cholesterol levels were positively related to estrone, estradiol, and androstenedione levels. It is premature to attribute the sex differential in lipid cardiovascular risk profiles to higher levels of testosterone per se in men, since testosterone levels are favorably associated with cardiovascular risk while estrogen levels have the converse relation in men. The differing effects and interactions of specific endogenous sex hormones in men and women require further elucidation.

Relation of serum testosterone levels to high density lipoprotein cholesterol and other characteristics in men

Although levels of high density lipoprotein (HDL) cholesterol in males decrease during adolescence and after treatment with testosterone derivatives, several studies have reported that levels of HDL cholesterol are positively associated with endogenous levels of testosterone in men. This association was further examined using data collected during 1985 and 1986 from 3,562 white and 500 black men who ranged in age from 31 to 45 years. Black men had higher mean levels of both HDL cholesterol (8 mg/dl) and total testosterone (33 ng/dl) than white men, and positive associations were observed between testosterone and HDL cholesterol levels (r = 0.22, whites; r = 0.26, blacks). In addition, levels of testosterone were related positively to alcohol consumption and cigarette smoking and negatively to age, Quetelet index, and use of beta-blockers. We used stratification and regression analyses to determine if any of these characteristics could account for the positive association between levels of HDL cholesterol and total testosterone. Although controlling for most factors had little influence, adjusting for Quetelet index reduced the strength of the association between levels of testosterone and HDL cholesterol by approximately 30%. These findings suggest that the positive association between levels of testosterone and HDL cholesterol may not be causal. Multivariable analyses that control for obesity and other potentially confounding characteristics should be used in studies that assess the relation of testosterone levels to coronary heart disease.

Is baldness a risk factor for coronary artery disease? A review of the literature

A literature search identified eight articles containing data on both baldness and coronary artery disease (CAD). Three of these articles described case-control studies that showed a positive relationship between baldness and CAD when controlling for CAD risk factors. Three other case-control studies showed no such relationship, but these did not control for CAD risk factors. The results of two cohort studies were inconclusive. Insufficient data were available from these studies to analyze possible relationships between baldness and CAD risk factors themselves. Overall, the data reviewed suggest that a small risk of CAD due to baldness may exist, but this risk is smaller than that of well-known CAD risk factors such as smoking and hypertension. Future research should emphasize proper control for age and CAD risk factors.

Sex hormones and lipoproteins in men

PURPOSE

To clarify the conflicting evidence of an association between endogenous sex hormones and lipoprotein metabolism in men, we examined the relationship between sex hormone levels, total cholesterol, and high-density lipoprotein cholesterol (HDL-C), taking into account the coronary artery disease (CAD) status of the subjects.

PATIENTS AND METHODS

Sex hormone levels, total cholesterol, and HDL-C were measured in 67 men with CAD from among 191 consecutive male patients between the ages of 25 and 75 undergoing coronary angiography, in 26 men without angiographic evidence of CAD, and in 55 men who were clinically free of CAD.

RESULTS

There was a consistently positive correlation between total estradiol or calculated free estradiol and both total cholesterol and HDL-C, which persisted after adjustment for potential confounders. Total cholesterol was associated with total testosterone after controlling for age, adiposity, and the presence or absence of CAD, but not with calculated free testosterone. No association was noted between total testosterone or calculated free testosterone and HDL-C. A significant interaction was observed between estradiol and testosterone with respect to total cholesterol.

CONCLUSION

This study demonstrates an association between sex hormone levels and lipoprotein metabolism, specifically between estradiol levels and both total cholesterol and HDL-C. Unlike most previous investigators, we were able both to control for the CAD status of our subjects and to consider unbound, biologically active hormone levels. In addition, we documented a complex interaction between endogenous testosterone and estradiol in relation to lipoprotein levels; this association should be considered in future studies.

Relationships of plasma lipoprotein concentrations to unbound, albumin-bound and sex hormone-binding globulin-bound fractions of gonadal steroids in men

Most epidemiologic studies of plasma lipoproteins and gonadal steroids have measured total hormone concentrations only. Gonadal steroids are transported in plasma in unbound, albumin-bound and sex hormone-binding globulin (SHBG)-bound forms, only the first two of which are biologically active. In the present study the associations of plasma lipoproteins with the different fractions of testosterone, oestradiol and 5 alpha-dihydrotestosterone (5 alpha DHT) were explored by multiple regression in 70 men aged 52-67 years (mean, 59 years). The principal finding was that the distribution of cholesterol between the two major subclasses of high density lipoprotein (HDL) was correlated with the concentrations of unbound and albumin-bound oestradiol, but not with SHBG-bound oestradiol or any fraction of testosterone or 5 alpha DHT. These associations were independent of plasma triglyceride. Apoproteins A-I and A-II were not correlated with any hormone fraction. Thus, in middle-aged/elderly men HDL subclasses appear to be influenced by circulating estrogenic activity, but not by androgenic activity, through a mechanism that is unrelated to triglyceride transport or HDL apoprotein metabolism.

Association of decreased sex hormone binding globulin and cardiovascular risk factors

Sex hormones play a major role in determining the risk of cardiovascular disease. While earlier studies have shown that reduced sex hormone binding globulin (SHBG) is associated with increased glucose and insulin concentrations in premenopausal women, few data exist on the relationship of SHBG to other cardiovascular risk factors in women. We hypothesized that decreased SHBG would be associated with an atherogenic pattern of cardiovascular risk factors. We measured total testosterone, total estradiol and SHBG, lipids and lipoproteins, glucose and insulin, and systolic and diastolic blood pressure in 96 premenopausal women. Although total testosterone and total estradiol were not related to cardiovascular risk factors, SHBG was negatively associated with triglyceride concentration (r = -0.37) and positively associated with high density lipoprotein cholesterol (HDLC) (r = 0.42). After adjustment for overall adiposity (body mass index) and upper body adiposity (as measured by the ratio of waist-to-hip circumferences), SHBG was still positively related to HDLC, but not to triglyceride. Adjustment for insulin abolished the relationship between SHBG and triglyceride levels, but did not alter the relationship between SHBG and HDLC. Sex hormones were not related to either systolic or diastolic blood pressure.

Endogenous sex hormones and cardiovascular disease in men. A prospective population-based study

Plasma obtained and frozen in 1972-1974 from 1,009 white men (40-79 years old) who have been followed for 12 years was examined for endogenous sex hormone levels according to prevalent or subsequent cardiovascular disease. In these older men, no sex hormone measured (testosterone, androstenedione, estrone, or estradiol) was significantly associated with known cardiovascular disease at baseline or with subsequent cardiovascular mortality or ischemic heart disease morbidity or mortality. Sex hormone-binding globulin levels were also similar by disease status. Analyses of hormone:sex hormone-binding globulin ratios or of estrogen:androgen ratios showed a similar lack of association with cardiovascular disease. Testosterone levels were significantly inversely associated with levels of blood pressure, fasting plasma glucose, and triglyceride and body mass index. In contrast, the only significant estrogen risk factor associations were positive correlations of estrone with total plasma cholesterol, triglyceride, and glucose. These data do not support a causal role for elevated endogenous estrogen levels and heart disease.

Relationship between sex hormones and haemostatic factors in healthy middle-aged men

Associations of plasma testosterone and estradiol with some haemostatic factors (factor VII activity, fibrinogen, antithrombin III and alpha 2-antiplasmin) were cross-sectionally examined in 251 healthy, middle-aged men participating in the Paris Prospective Study II on risk factors for ischaemic heart disease. Testosterone levels were negatively correlated to factor VII activity and alpha 2-antiplasmin, the main inhibitor of fibrinolysis. No association was found either between testosterone levels and both fibrinogen and antithrombin III, or between estradiol levels and the set of haemostatic variables. The associations between testosterone and both factor VIIc and alpha 2-antiplasmin were independent of HDL-cholesterol, LDL-cholesterol, triglycerides, smoking, alcohol, body mass index and blood pressure. These results suggest that low circulating testosterone levels might be associated with a hypercoagulability state and therefore could contribute to an increased risk of IHD.

Genetic analysis of strains C57BL/6J and BALB/cJ for Ath-1, a gene determining atherosclerosis susceptibility in mice

We previously reported that mice have at least one major gene determining atherosclerosis susceptibility, Ath-1. Susceptible alleles of Ath-1 are found in strain C57BL/6J and are associated with relatively low levels of high-density lipoprotein cholesterol (HDL-C) when these mice are fed an atherogenic diet. Resistant alleles of Ath-1 are found in strains C3H/HeJ and BALB/cJ and are associated with relatively high levels of HDL-C. Data reported earlier from the set of seven recombinant inbred (RI) strains, derived from C57BL/6By and BALB/cBy, showed that these parental strains differed at Ath-1. However, due to the limited number of RI strains, it was not possible to determine with certainty whether Ath-1 was the only major gene determining atherosclerosis susceptibility in these two strains or to determine its map position accurately. In this report, examination of F1, F2, and backcross progeny from a cross between C57BL/6J and BALB/cJ demonstrates that Ath-1 is the major gene determining atherosclerotic lesion formation and HDL-C levels in female mice. The data from male animals suggest that environmental factors or modifying genes also influence male HDL-C levels and thus partly obscure the Ath-1 phenotype. HDL-C levels in F1 progeny resemble the BALB/c parent. The data from the cross provide confirmatory evidence that Ath-1 is linked to Alp-2 on chromosome 1 with a map distance of 4.8 +/- 2.3 (SE). Combining these data with a previous cross between strain C57BL/6 and strain C3H/HeJ gives a map distance between Ath-1 and Alp-2 of 4.9 +/- 1.8 based on 7 crossovers found among 144 tested chromosomes.

Sex, plasma lipoproteins, and atherosclerosis: prevailing assumptions and outstanding questions

We review the hypothesis that the incidence of coronary heart disease (CHD) is higher in men than in women due to differences in plasma lipoprotein risk factors between the sexes. Men and women appear to be equally susceptible to the effects of lipoprotein risk factors for CHD, and the difference between the sexes in lipoprotein risk factors for CHD appears to be consistent with their being, at least in part, responsible for the sex difference in CHD. This is apparent both when men and women of equal age are compared, and when age-related variations in the sex differences in plasma lipoproteins and CHD are considered. Differences between the sexes in lipoprotein concentrations are still present when sex differences in adiposity, cigarette smoking, physical activity, and diet are taken into account. Evidence relating these sex differences in CHD and lipoproteins to the effects of sex hormones is critically examined. It is commonly accepted that androgens induce changes in lipoprotein concentrations that would predispose towards CHD, whereas estrogens are held to have opposite effects. However, much of the evidence for this comes from studies of changes associated with administration of synthetic gonadal steroids or with changes in gonadal function. Studies of differences in lipoprotein metabolism in normal men and women are extremely limited. In males high-density lipoprotein (HDL) cholesterol levels fall at puberty, correlating with the rise in plasma testosterone concentrations. In females, HDL levels do not change at puberty, despite the rise in estrogen concentrations. Evidence for lipoprotein changes during the menopause, when estrogen levels decline, is equivocal. Similarly, the evidence for an increase in CHD incidence at the menopause is inconclusive. National mortality data indicate that the decreasing sex difference in CHD after 50 years of age is due to a declining rate of increase in men rather than to an acceleration in CHD incidence in women. In men the age-related increase in low-density lipoprotein (LDL) concentrations diminishes beyond 50 years of age, whereas in women the rate of increase remains unchanged. Studies of the effects of gonadectomy are of doubtful relevance in assessing the roles of sex hormones in CHD, and have not been performed with sufficient rigor to provide definitive conclusions.(ABSTRACT TRUNCATED AT 400 WORDS)

Comparison of atherosclerotic lesions and HDL-lipid levels in male, female, and testosterone-treated female mice from strains C57BL/6, BALB/c, and C3H

In order to determine whether male and female mice differed in HDL-lipid levels or in atherosclerotic response to a high fat diet, we examined 3 inbred strains which differed in susceptibility to atherosclerosis; C57BL/6, BALB/c, and C3H. Mice were fed normal chow or an atherogenic diet containing 1.25% cholesterol, 15% fat, and 0.5% cholic acid. Lesion number and size were determined after 14 weeks on the diet; plasma HDL-lipid levels were determined at 0 and 4 weeks on the diet. For C3H, the most atherosclerosis-resistant strain, HDL-lipid levels were very high and not affected by sex or diet. For BALB/c, HDL-lipid levels were intermediate between the other two strains. Male levels were significantly higher than the females, and the atherogenic diet caused a drop in HDL-lipid levels of 14-27% depending on sex. For C57BL/6, the most atherosclerosis-susceptible strain, HDL-lipid levels were low compared to the other two strains. Males and females on normal chow did not differ in HDL-lipid, but females showed a 50% decrease in HDL when fed the atherogenic diet. For both BALB/c and C57BL/6, testosterone-treated females resembled the males. The HDL-lipid levels in mice on atherogenic diet differed over a 3-fold range among the nine groups. When HDL-lipid levels were compared to the number of atherosclerotic lesions or the total lesion area, a high degree of correlation was observed (r = -0.95 for lesion number and -0.93 for total lesion area). This suggests that HDL-lipid levels are important in determining atherosclerosis susceptibility in mice.

Increase in plasma high-density lipoprotein concentration following complete androgen blockage in men with prostatic carcinoma

There is evidence that endogenous estrogens have a positive effect on plasma high density lipoprotein (HDL) concentration, whereas the relation between HDL and male sex hormones is unclear, since both positive and negative effects have been reported. This study examined the effects of LHRH agonist in combination with an antiandrogen on plasma lipids and lipoproteins in 17 elderly men with prostatic carcinoma. Subjects were examined prior to and after therapy at 4-week intervals up to 16 weeks. Prior to therapy, their lipid and lipoprotein profiles were not significantly different from a control group composed of individuals of similar age and living in the same community area. Following therapy plasma levels of testosterone and dihydrotestosterone were markedly decreased (above 90%) and their residual activity neutralized through effective use of an antiandrogen. Plasma estradiol decreased between 65% and 85% and the concentration of cortisol was unaffected. The very low density lipoprotein (VLDL) apo-B decreased and low density lipoprotein (LDL) apo-B increased; thus, no change was observed in the total plasma apo-B levels. Total plasma cholesterol increased by 6% (baseline v peak values, mg/dL, mean +/- SEM; 219 +/- 9 v 233 +/- 9, P less than 0.05) due to a significant rise in HDL cholesterol concentration (45.5 +/- 2.8 v 56.5 +/- 3.6, P less than 0.01). Both VLDL and LDL cholesterol levels remained unchanged. The mean elevation of 21% in HDL cholesterol was accompanied by a significant rise in HDL apo-A concentration (161 +/- 6 v 193 +/- 10, P less than 0.01), thus suggesting an increase in HDL mass and/or particle number.(ABSTRACT TRUNCATED AT 250 WORDS)

Low serum apolipoprotein A-I in acute myocardial infarction survivors with normal HDL cholesterol

High density lipoprotein (HDL) cholesterol, apolipoprotein A-I (apo A-I), gamma-glutamyl-transferase, testosterone and oestradiol were determined in plasma in non-diabetic males who had survived an acute myocardial infarction (AMI) before the age of 60. They also had serum levels of cholesterol below 7.0 mmol/l 1 year after the AMI. On the basis of diastolic blood pressure they were subdivided into 2 groups with diastolic blood pressures below 90 mm Hg (n = 39), and with or above 95 mm Hg (n = 21) and then compared with an age-matched male non-diabetic reference group (n = 32). There were no significant differences in the levels of HDL cholesterol, gamma-glutamyl-transferase, and sex hormones between the AMI groups and the reference group. Reduced plasma levels of apo A-I were found in the AMI groups.

Long-term transdermal dihydrotestosterone therapy: effects on pituitary gonadal axis and plasma lipoproteins

In order to investigate whether dihydrotestosterone (DHT) alone has an inhibiting effect on pituitary luteinizing hormone (LH) secretion, and whether this natural androgen has any effect on plasma lipids when administered transdermally, dihydrotestosterone was applied for 3 mth in a daily dose of 125 or 250 mg in gel form for transdermal absorption (Andractim) to elderly males with relatively low plasma testosterone levels. The results clearly show that DHT inhibits LH secretion, as plasma LH levels were decreased, although testosterone, free testosterone, estradiol and free estradiol levels were decreased. Regarding plasma lipid levels, DHT administration for 3 mth resulted in a moderate decrease in plasma cholesterol and low-density lipoprotein (LDL) levels, and a slight decrease in high-density lipoprotein (HDL)-cholesterol levels, the HDL/TLC ratio remaining constant. This suggests that percutaneous DHT administration is a relatively safe modality of androgen replacement therapy as far as atherogenicity is concerned.

Serum high density lipoprotein subclasses, testosterone and sex-hormone-binding globulin in Trinidadian men of African and Indian descent

Serum high-density lipoprotein (HDL) cholesterol, testosterone and sex-hormone-binding globulin (SHBG) were measured in 300 men, aged 35-64 years, of African and Indian descent who represented a 40% sample of participants in a community survey of coronary heart disease in Trinidad. Free testosterone was calculated from total testosterone and SHBG. In 113 men, HDL2 and HDL3 cholesterol were measured by a precipitation technique. Indian men had a significantly lower HDL-cholesterol concentration than African men (P = 0.003), which is known to be due to a reduction in the HDL3 fraction (demonstrable only in younger men in the subsample drawn for this study). Testosterone did not differ with ethnic group, but SHBG was reduced in Indians (P = 0.03). After allowance for age, ethnic group, alcohol consumption and smoking habit, HDL cholesterol was associated positively with SHBG (P = 0.025) but was not related significantly to either total testosterone or its free and bound components. Serum HDL2 cholesterol was associated positively and independently with SHBG (P = 0.001) and total and bound testosterone (P = 0.002), whereas HDL3 cholesterol showed no significant associations with these factors. Neither SHBG or testosterone afforded an explanation for the relatively low HDL and HDL3 cholesterol concentrations in Indian men.