Are published normal ranges of serum testosterone too high? Results of a cross-sectional survey of serum testosterone and luteinizing hormone in healthy men

Analysis of diurnal variation in serum testosterone levels in men with symptoms of testosterone deficiency

BACKGROUND

Testosterone (T) plays a crucial role in various physiological functions in men, and understanding the variations in T levels during the day is essential for diagnosing and treating testosterone deficiency (TD).

AIM

We sought to evaluate the reduction in serum total T (TT) levels throughout the day in men with symptoms of testosterone deficiency and to determine the variables having an impact on the extent of this decline.

METHODS

The study population consisted of a group of men who within 3 months of each other had all undergone both early morning and afternoon TT level measurements. We did not include patients with a history of a prior orchiectomy, testosterone levels below 100 ng/dL or above 1000 ng/dL, a history of androgen deprivation therapy, or patients on T therapy. Statistical analyses were conducted using descriptive statistics, t-tests, chi-square tests, and correlation calculations. Liquid chromatography-tandem mass spectrometry was used to measure TT, and a change in TT levels greater than 100 ng/dL was considered significant. Using multivariable and univariable analysis, we attempted to define predictors of a decrease in afternoon TT levels.

OUTCOMES

The majority of men showed no significant difference in T levels between morning and afternoon.

RESULTS

In total, 506 men with a median age of 65 years were analyzed. The most common comorbidities were hypertension and hyperlipidemia. Levels of TT were measured in the morning and afternoon, and no significant differences in mean T levels based on the time of the test were found. Age was not significantly associated with T levels.

CLINICAL IMPLICATIONS

There was a weak negative correlation between age and the difference between morning and afternoon T levels, with younger men showing more significant variations in T levels. The most considerable differences in T levels were observed in men younger than 30 years. There were no predictors of the magnitude of the T decrease in the afternoon.

STRENGTHS AND LIMITATIONS

Strengths of the study include the number of subjects and the use of liquid chromatography-tandem mass spectrometry for T measurement. Limitations include failure to measure morning and afternoon T levels on the same day, the retrospective nature of the study, and a smaller sample size of patients younger than 30 years.

CONCLUSION

In this study we found no strong link between age and daily T fluctuation, but we observed a decrease in the magnitude of variation with aging. The group experiencing the most significant decline in daily T had higher morning and consistently normal afternoon T levels.

Understanding One Half of the Sex Difference Equation: The Modulatory Effects of Testosterone on Diabetic Cardiomyopathy

Diabetes is a prevalent disease, primarily characterized by high blood sugar (hyperglycemia). Significantly higher rates of myocardial dysfunction have been noted in individuals with diabetes, even in those without coronary artery disease or high blood pressure (hypertension). Numerous molecular mechanisms have been identified through which diabetes contributes to the pathology of diabetic cardiomyopathy, which presents as cardiac hypertrophy and fibrosis. At the cellular level, oxidative stress and inflammation in cardiomyocytes are triggered by hyperglycemia. Although males are generally more likely to develop cardiovascular disease than females, diabetic males are less likely to develop diabetic cardiomyopathy than are diabetic females. One reason for these differences may be the higher levels of serum testosterone in males compared with females. Although testosterone appears to protect against cardiomyocyte oxidative stress and exacerbate hypertrophy, its role in inflammation and fibrosis is much less clear. Additional preclinical and clinical studies will be required to delineate testosterone's effect on the diabetic heart.

Guidelines on the use of sex and gender in cardiovascular research

In cardiovascular research, sex and gender have not typically been considered in research design and reporting until recently. This has resulted in clinical research findings from which not only all women, but also gender-diverse individuals have been excluded. The resulting dearth of data has led to a lack of sex- and gender-specific clinical guidelines and raises serious questions about evidence-based care. Basic research has also excluded considerations of sex. Including sex and/or gender as research variables not only has the potential to improve the health of society overall now, but it also provides a foundation of knowledge on which to build future advances. The goal of this guidelines article is to provide advice on best practices to include sex and gender considerations in study design, as well as data collection, analysis, and interpretation to optimally establish rigor and reproducibility needed to inform clinical decision-making and improve outcomes. In cardiovascular physiology, incorporating sex and gender is a necessary component when optimally designing and executing research plans. The guidelines serve as the first guidance on how to include sex and gender in cardiovascular research. We provide here a beginning path toward achieving this goal and improve the ability of the research community to interpret results through a sex and gender lens to enable comparison across studies and laboratories, resulting in better health for all.

Analytical Methods for the Determination of Neuroactive Steroids

Neuroactive steroids are a family of all steroid-based compounds, of both natural and synthetic origin, which can affect the nervous system functions. Their biosynthesis occurs directly in the nervous system (so-called neurosteroids) or in peripheral endocrine tissues (hormonal steroids). Steroid hormone levels may fluctuate due to physiological changes during life and various pathological conditions affecting individuals. A deeper understanding of neuroactive steroids' production, in addition to reliable monitoring of their levels in various biological matrices, may be useful in the prevention, diagnosis, monitoring, and treatment of some neurodegenerative and psychiatric diseases. The aim of this review is to highlight the most relevant methods currently available for analysis of neuroactive steroids, with an emphasis on immunoanalytical methods and gas, or liquid chromatography combined with mass spectrometry.

Association of hypogonadism symptoms and serum hormones in aging males

The association between hypogonadism symptoms and the levels of serum hormones are still in debate. To investigate the relationship between hypogonadism symptoms and serum hormones in middle-aged and elderly Chinese men, this community-based cross-sectional study was conducted based on a total of 965 ageing men. The ageing males' symptom (AMS) scale, International Index of Erectile Function-5 (IIEF-5), International Prostate Symptom Score (IPSS) questionnaires and related variables were assessed. Blood tests for total testosterone (TT), sex hormone-binding globulin (SHBG) and luteinising hormone (LH) were performed. Serum level of free testosterone (FT) and bioavailable testosterone (Bio-T) was calculated. The mean age was 56.34 ± 8.85 years. Total AMS score was significantly associated with all five serum hormones (LH: p < 0.001; SHBG: p < 0.001; TT: p =.043; FT: p = 0.007; Bio-T: p < 0.001). We identified sexual and somatic symptoms were obviously related to five serum hormones, while psychological symptoms seemed to have no association with serum hormones. After adjusting for age and BMI, multiple linear regression analysis indicated that LH had positive correlations with total AMS score, somatic and sexual symptom score (p < 0.05). In conclusion, LH and SHBG had the strongest correlation hypogonadism and might be used as early predictors for symptomatic hypogonadism in the near future.

Reference Intervals of Total Testosterone in Adult Filipino Men

BACKGROUND

The reference range of total testosterone needs to be established locally as ethnic differences in adiposity, insulin sensitivity, and sex hormone-binding globulin (SHBG) levels may affect total testosterone levels. The aim of this study is to establish the reference intervals of total testosterone from healthy, young adult Filipino males.

METHODS

The study included 110 healthy, Filipino male volunteers aged 21-40, studying or working at the University of the Philippines Manila. Clinical history, height, weight, body mass index (BMI), and blood pressure (BP) were obtained, and blood for total testosterone, SHBG, albumin, insulin, fasting blood sugar (FBS), and total cholesterol was collected. Free testosterone was calculated using Vermeulen's formula. The 2.5th to 97.5th percentiles of subjects for total testosterone were used as the normative range for Filipino men.

RESULTS

The reference range of total testosterone is 7.33-53.01 nmol/L.

CONCLUSION

The present study derived reference ranges of total testosterone using data from apparently healthy, young adult men to support clinical services.

RNA-mediated gene fusion in mammalian cells

One of the hallmarks of cancer is the formation of oncogenic fusion genes as a result of chromosomal translocations. Fusion genes are presumed to form before fusion RNA expression. However, studies have reported the presence of fusion RNAs in individuals who were negative for chromosomal translocations. These observations give rise to "the cart before the horse" hypothesis, in which the genesis of a fusion RNA precedes the fusion gene. The fusion RNA then guides the genomic rearrangements that ultimately result in a gene fusion. However, RNA-mediated genomic rearrangements in mammalian cells have never been demonstrated. Here we provide evidence that expression of a chimeric RNA drives formation of a specified gene fusion via genomic rearrangement in mammalian cells. The process is: (i) specified by the sequence of chimeric RNA involved, (ii) facilitated by physiological hormone levels, (iii) permissible regardless of intrachromosomal (TMPRSS2-ERG) or interchromosomal (TMPRSS2-ETV1) fusion, and (iv) can occur in normal cells before malignant transformation. We demonstrate that, contrary to "the cart before the horse" model, it is the antisense rather than sense chimeric RNAs that effectively drive gene fusion, and that this disparity can be explained by transcriptional conflict. Furthermore, we identified an endogenous RNA AZI1 that functions as the "initiator" RNA to induce TMPRSS2-ERG fusion. RNA-driven gene fusion demonstrated in this report provides important insight in early disease mechanisms, and could have fundamental implications in the biology of mammalian genome stability, as well as gene-editing technology via mechanisms native to mammalian cells.

Photonic Molecularly Imprinted Polymer Film for the Detection of Testosterone in Aqueous Samples

The detection of testosterone in aqueous solutions is a difficult task due to the low concentration levels that are relevant in environmental and physiological samples. Current analytical methods are expensive and/or complex. To address this issue, we fabricated a molecularly imprinted polymer (MIP) photonic film for the detection of testosterone in water. The films were obtained using colloidal crystals as templates for the pore morphology. Monodispersed silica particles with an average diameter 330 nm were used to obtain the colloidal crystal by vertical deposition. A solution of acrylic acid with testosterone as the imprinted template was infiltrated in the colloidal crystal and polymerized via bulk polymerization; the particles were then removed by acid etching and the testosterone eluted by a suitable solvent. The material was characterized by FTIR, swelling experiments and microscopy; MIPs were investigated by equilibrium rebinding, kinetics and reuse experiments. The results showed that the MIPs exhibited selectivity to the template, a 30-min equilibration time and stability after at least six cycles of use and regeneration. After incubation, the reflectance spectra of the films showed a shift of the Bragg diffraction peak that correlated with testosterone concentration in the 5–100 ppb range.

Harmonized Reference Ranges for Circulating Testosterone Levels in Men of Four Cohort Studies in the United States and Europe

Background

Reference ranges for testosterone are essential for making a diagnosis of hypogonadism in men.

Objective

To establish harmonized reference ranges for total testosterone in men that can be applied across laboratories by cross-calibrating assays to a reference method and standard.

Population

The 9054 community-dwelling men in cohort studies in the United States and Europe: Framingham Heart Study; European Male Aging Study; Osteoporotic Fractures in Men Study; and Male Sibling Study of Osteoporosis.

Methods

Testosterone concentrations in 100 participants in each of the four cohorts were measured using a reference method at Centers for Disease Control and Prevention (CDC). Generalized additive models and Bland-Altman analyses supported the use of normalizing equations for transformation between cohort-specific and CDC values. Normalizing equations, generated using Passing-Bablok regression, were used to generate harmonized values, which were used to derive standardized, age-specific reference ranges.

Results

Harmonization procedure reduced intercohort variation between testosterone measurements in men of similar ages. In healthy nonobese men, 19 to 39 years, harmonized 2.5th, 5th, 50th, 95th, and 97.5th percentile values were 264, 303, 531, 852, and 916 ng/dL, respectively. Age-specific harmonized testosterone concentrations in nonobese men were similar across cohorts and greater than in all men.

Conclusion

Harmonized normal range in a healthy nonobese population of European and American men, 19 to 39 years, is 264 to 916 ng/dL. A substantial proportion of intercohort variation in testosterone levels is due to assay differences. These data demonstrate the feasibility of generating harmonized reference ranges for testosterone that can be applied to assays, which have been calibrated to a reference method and calibrator.

Growth Inhibition by Testosterone in an Androgen Receptor Splice Variant-Driven Prostate Cancer Model

BACKGROUND

Castration resistance creates a significant problem in the treatment of prostate cancer. Constitutively active splice variants of androgen receptor (AR) have emerged as drivers for resistance to androgen deprivation therapy, including the next-generation androgen-AR axis inhibitors abiraterone and enzalutamide. In this study, we describe the characteristics of a novel castration-resistant prostate cancer (CRPC) model, designated JDCaP-hr (hormone refractory).

METHODS

JDCaP-hr was established from an androgen-dependent JDCaP xenograft model after surgical castration. The expression of AR and its splice variants in JDCaP-hr was evaluated by immunoblotting and quantitative reverse transcription-polymerase chain reaction. The effects of AR antagonists and testosterone on JDCaP-hr were evaluated in vivo and in vitro. The roles of full-length AR (AR-FL) and AR-V7 in JDCaP-hr cell growth were evaluated using RNA interference.

RESULTS

JDCaP-hr acquired a C-terminally truncated AR protein during progression from the parental JDCaP. The expression of AR-FL and AR-V7 mRNA was upregulated by 10-fold in JDCaP-hr compared with that in JDCaP, indicating that the JDCaP and JDCaP-hr models simulate castration resistance with some clinical features, such as overexpression of AR and its splice variants. The AR antagonist bicalutamide did not affect JDCaP-hr xenograft growth, and importantly, testosterone induced tumor regression. In vitro analysis demonstrated that androgen-independent prostate-specific antigen secretion and cell proliferation of JDCaP-hr were predominantly mediated by AR-V7. JDCaP-hr cell growth displayed a bell-shaped dependence on testosterone, and it was suppressed by physiological concentrations of testosterone. Testosterone induced rapid downregulation of both AR-FL and AR-V7 expression at physiological concentrations and suppressed expression of the AR target gene KLK3.

CONCLUSIONS

Our findings support the clinical value of testosterone therapy, including bipolar androgen therapy, in the treatment of AR-overexpressed CRPC driven by AR splice variants that are not clinically actionable at present. Prostate 76:1536-1545, 2016. © 2016 Wiley Periodicals, Inc.

Comparing calculated free testosterone with total testosterone for screening and diagnosing late-onset hypogonadism in aged males: A cross-sectional study

OBJECTIVE

The aim of this study is to compare calculated free testosterone (cFT) and total testosterone (T) in predicting late-onset hypogonadism (LOH) in middle-aged and elderly males.

METHODS

We surveyed a random sample of 608 males between the ages of 45 and 87 years from Shanghai, China. The Aging Male Symptoms (AMS) questionnaire and the Androgen Deficiency in Aging Male (ADAM) questionnaire were completed by the subjects. Testosterone (T), sex hormone-binding globulin (SHBG), albumin, and other blood biochemical indexes were measured in 332 males. The corresponding cFT was obtained using the Vermeulen formula and the correlations between T and cFT were analyzed by SPSS statistical software.

RESULTS

Among the 332 males who underwent biochemical evaluation, 289 males (87.0%) was positively screened by the ADAM questionnaire and 232 males (69.9%) by the AMS questionnaire. As suggested by linear regression, cFT exhibited a negative correlation with age in both ADAM+ and AMS+ group, whereas T did not appear to have significant correlation with age. Besides, there were statistically significant differences in cFT (P<.001) in the AMS questionnaire.

CONCLUSIONS

Calculated free testosterone levels are more reliable than T levels for diagnosing LOH in middle-aged and elderly males.

Dynamic alteration of serum testosterone with aging: a cross-sectional study from Shanghai, China

BACKGROUND

Level of the testosterone in a man's life span is very important. Studies on the serum testosterone concentrations in different age groups of healthy men were controversial. The aim of this study was to investigate dynamic changes of serum reproductive hormones with aging in healthy Chinese male and to compare its correlation with age.

METHODS

Total of 1,093 healthy Chinese men from Shanghai aged from 20 to 87  years old was enrolled in the study. Concentrations of serum total testosterone (T), luteinizing hormone (LH) and sex hormone binding globulin (SHBG) were quantified by EIA. Testosterone secretion index (TSI) and free testosterone index (FTI) were then calculated. Data were analyzed by SPSS program. Non-parametric tests and univariate linear regression analyses were used.

RESULTS

The 1,039 male participants were grouped into 12 groups by 5-year apart for each group. Significant differences in T, LH, SHBG, FTI and TSI were found between the 12 different age groups. Average of serum total T was 15.36 ± 4.86 nmol/L; LH was 4.76 ± 2.76 IU/L, SHBG was 32.61 ± 17.24 nmol/L. Compared to age 20 ~ 24 group, serum T level of age 35 ~ 39, 40 ~ 44, 45 ~ 49, 50 ~ 54, and 55 ~ 59 was significantly decreased (p < 0.05). Intriguingly, however, serum T level of age 60 or older did not significantly reduced compared to the age of 20 ~ 24 group. Serum LH and SHBG were positively correlated with aging (p <0.01), while TSI and FTI were negatively correlated with aging (p <0.01). In addition, BMI was negatively and significantly correlated with levels of T (r = -0.585, p < 0.001), LH (r = -0.090, p < 0.001), SHBG (r = - 1.817, p < 0.001), and TSI (r = - 0.104, p < 0.001), but positively and significantly correlated with FTI level (r = 0.011, p < 0.001).

CONCLUSION

Serum total testosterone fluctuated with aging in adult men, and FTI and TSI decreased gradually with aging. While age was not significantly correlated with T level, BMI was significantly and negatively correlated with T level, suggesting body weight may affect testosterone level.

A validated age-related normative model for male total testosterone shows increasing variance but no decline after age 40 years

The diagnosis of hypogonadism in human males includes identification of low serum testosterone levels, and hence there is an underlying assumption that normal ranges of testosterone for the healthy population are known for all ages. However, to our knowledge, no such reference model exists in the literature, and hence the availability of an applicable biochemical reference range would be helpful for the clinical assessment of hypogonadal men. In this study, using model selection and validation analysis of data identified and extracted from thirteen studies, we derive and validate a normative model of total testosterone across the lifespan in healthy men. We show that total testosterone peaks [mean (2.5-97.5 percentile)] at 15.4 (7.2-31.1) nmol/L at an average age of 19 years, and falls in the average case [mean (2.5-97.5 percentile)] to 13.0 (6.6-25.3) nmol/L by age 40 years, but we find no evidence for a further fall in mean total testosterone with increasing age through to old age. However we do show that there is an increased variation in total testosterone levels with advancing age after age 40 years. This model provides the age related reference ranges needed to support research and clinical decision making in males who have symptoms that may be due to hypogonadism.

Reference ranges for testosterone in men generated using liquid chromatography tandem mass spectrometry in a community-based sample of healthy nonobese young men in the Framingham Heart Study and applied to three geographically distinct cohorts

CONTEXT

Reference ranges are essential for partitioning testosterone levels into low or normal and making the diagnosis of androgen deficiency. We established reference ranges for total testosterone (TT) and free testosterone (FT) in a community-based sample of men.

METHODS

TT was measured using liquid chromatography tandem mass spectrometry in nonobese healthy men, 19-40 yr old, in the Framingham Heart Study Generation 3; FT was calculated. Values below the 2.5th percentile of reference sample were deemed low. We determined the association of low TT and FT with physical dysfunction, sexual symptoms [European Male Aging Study (EMAS) only], and diabetes mellitus in three cohorts: Framingham Heart Study generations 2 and 3, EMAS, and the Osteoporotic Fractures in Men Study.

RESULTS

In a reference sample of 456 men, mean (sd), median (quartile), and 2.5th percentile values were 723.8 (221.1), 698.7 (296.5), and 348.3 ng/dl for TT and 141. 8 (45.0), 134.0 (60.0), and 70.0 pg/ml for FT, respectively. In all three samples, men with low TT and FT were more likely to have slow walking speed, difficulty climbing stairs, or frailty and diabetes than those with normal levels. In EMAS, men with low TT and FT were more likely to report sexual symptoms than men with normal levels. Men with low TT and FT were more likely to have at least one of the following: sexual symptoms (EMAS only), physical dysfunction, or diabetes.

CONCLUSION

Reference ranges generated in a community-based sample of men provide a rational basis for categorizing testosterone levels as low or normal. Men with low TT or FT by these criteria had higher prevalence of physical dysfunction, sexual dysfunction, and diabetes. These reference limits should be validated prospectively in relation to incident outcomes and in randomized trials.

The influence of age on bioavailable and free testosterone is independent of body mass index and glucose levels

PURPOSE

To evaluate the influence of age on serum levels of total testosterone (TT), bioavailable testosterone (BT), free testosterone (FT), and sex-hormone binding globulin (SHBG), considering the presence of fasting blood glucose levels and body mass index (BMI) in a selected male population.

METHODS

A total of 428 men were analyzed. Anthropometry was taken from all, considering BMI as general obesity indicative variable. Fasting blood samples were drawn for determination of plasma glucose levels and serum levels of albumin, TT, and SHBG. The values of BT and FT were calculated from TT, SHBG, and albumin, by Vermeulen's equation. Statistical significance was set at P ≤ 0.05.

RESULTS

Age was negatively correlated to BT (r = -0.301; P < 0.001) and FT (r = -0.273; P < 0.001), but not to TT levels (r = 0.002, P = 0.974). Age was positively correlated to SHBG (r = 0.376; P < 0.001). Age was independently associated with the occurrence of high SHBG levels (OR = 1.07, 95%CI = 1.05-1.10, P < 0.001) and of low BT (OR = 1.04, 95%CI = 1.02-1.07, P < 0.001) and FT levels (OR = 1.05, 95%CI = 1.03-1.08, P < 0.001), but not with low levels of TT (P = 0.08).

CONCLUSIONS

Age was significantly associated to high levels of SHBG and to low levels of BT and FT, without significant association to TT. This pattern was independent of BMI and glucose levels.

Erectile dysfunction in opioid users: lack of association with serum testosterone

This study describes the prevalence of erectile dysfunction (ED) among 57 men using illicit opioids who presented to a primary care program for buprenorphine therapy. Participants' mean age was 40 years and 34% reported ED. Low total testosterone was detected in 17% of those reporting ED, but total testosterone was not significantly associated with ED. Examining multiple comorbidities and laboratory parameters, only older age was significantly associated with ED (r = .27, P< .05). ED is highly prevalent among men abusing opioids, but low total testosterone is rarely the cause.

Maternal smoking and developmental changes in luteinizing hormone (LH) and the LH receptor in the fetal testis

CONTEXT

The LH receptor (LHCGR) drives fetal testosterone secretion, which is vital for human masculinization. Maternal smoking is associated with defective masculinization, but the relationship between smoking, tropic hormones, testosterone, and functional LHCGR expression is poorly understood.

OBJECTIVE

This study aimed to investigate developmental changes in fetal gonadotropins, human chorionic gonadotropin (hCG), and expression of fetal testicular LHCGR isoforms and the effects of maternal cigarette smoking.

DESIGN

We conducted an observational study of the male fetus, comparing pregnancies in which the mothers did or did not smoke.

SETTING

The study was conducted at the Universities of Aberdeen and Glasgow.

PATIENTS/PARTICIPANTS

Testes and blood were collected from 54 morphologically normal human male fetuses of women undergoing elective termination of normal second-trimester pregnancies.

MAIN OUTCOME MEASURES

We measured circulating testosterone, hCG, LH, prolactin, FSH, and testicular LHCGR isoform expression.

RESULTS

Fetal testosterone and hCG, but not LH, significantly declined between 11 and 19 wk gestation with no significant change in testicular responsiveness. The proportion of nonfunctional LHCGR transcript in fetal testes was 2.3-fold lower than in adults. Fetal hCG was reduced 38% (P = 0.021) and the ratio of inactive vs. active LHCGR isoforms lowered by smoking.

CONCLUSIONS

Falling second-trimester fetal testosterone is probably due to declining maternal hCG because Leydig cell LH/hCG responsiveness remains constant. Although maternal cigarette smoking reduces fetal hCG, the ratio of inactive LHCGR isoforms is reduced and gonadotropin drive maintains testosterone production near control levels. The lower relative abundance of inactive isoforms compared with the adult testis reflects the importance of LHCGR.

Secular decline in male testosterone and sex hormone binding globulin serum levels in Danish population surveys

CONTEXT

Adverse secular trends in male reproductive health have been reported to be reflected in increased testicular cancer risk and decreased semen quality in more recently born men. These secular trends may also be reflected by changes in Leydig cell function.

OBJECTIVE

The objective of the study was to examine whether an age-independent time trend in male serum testosterone levels exists.

DESIGN AND SETTING

Testosterone and SHBG were analyzed in 5350 male serum samples from four large Danish population surveys conducted in 1982-1983, 1986-1987, 1991-1992, and 1999-2001. Free testosterone levels were calculated. The effects of age, year of birth, and time period on hormone levels were estimated in a general linear statistical model.

MAIN OUTCOME MEASURES

Testosterone, SHBG, and calculated free testosterone levels in Danish men in relation to age, study period, and year of birth were measured.

RESULTS

Serum testosterone levels decreased and SHBG levels increased with increasing age. In addition to this expected age effect, significant secular trends in testosterone and SHBG serum levels were observed in age-matched men with lower levels in the more recently born/studied men. No significant age-independent effect was observed for free testosterone. Adjustment for a concurrent secular increase in body mass index reduced the observed cohort/period-related changes in testosterone, which no longer were significant. The observed cohort/period-related changes in SHBG levels remained significant after adjustment for body mass index.

CONCLUSIONS

The observed age-independent changes in SHBG and testosterone may be explained by an initial change in SHBG levels, which subsequently lead to adjustment of testosterone at a lower level to sustain free testosterone levels.

The association of time of day and serum testosterone concentration in a large screening population

OBJECTIVE

To assess testosterone patterns during clinical hours in a large population of men participating in a national screening programme for prostate cancer, as the effect of time of day on serum testosterone concentration is unclear and largely reported in small studies.

SUBJECTS AND METHODS

Testosterone levels were measured in 3006 men attending the national Prostate Cancer Awareness Week screening programme. Blood samples were obtained between 06.00 and 18.00 hours, whenever men presented for screening. All men completed questionnaires on age, comorbidities, height and weight. Testosterone levels were compared based on four periods, i.e. T1, 06.00-10.00 (632 men), T2, 10.00-12.00 (812), T3, 12.00-14.00 (388), and T4, 14.00-18.00 hours (1174).

RESULTS

The mean (sd, range) age of the men was 60.3 (9.9, 40-94) years and the mean (sd) testosterone level was 415.2 (190.9) ng/dL. There was no change in mean (sd) testosterone levels over T1, T2 and T3, at 444.9 (206.2), 433.5 (195.8) and 434.4 (181.2) ng/dL, respectively, but levels at T4, at 380.4 (176.4) ng/dL, were lower by approximately 13% (P < 0.05). Advancing age, diabetes and obesity were associated with lower testosterone levels. The percentage of men with biochemical hypogonadism (<300 ng/dL) did not change across all four periods.

CONCLUSIONS

Testosterone levels in older men are stable throughout the morning and early afternoon, declining only modestly thereafter. Further case-controlled studies are needed to confirm these findings.

Mood changes, body mass index and bioavailable testosterone in healthy men: results of the Androx Vienna Municipality Study

OBJECTIVE

To determine whether sex hormones alone or in combination with body mass index (BMI) influence mood in men.

SUBJECTS AND METHODS

Blood samples were taken from 669 manual workers (aged 43-67 years) to measure sex hormone levels, in particular bioavailable testosterone (BAT). At the same time BMI was calculated. All participants completed the Beck's Depression Inventory (BDI) for the evaluation of depression. Then BMI and BAT were correlated to the BDI scores, to determine a possible interaction.

RESULTS

There was a quadratic main effect for BAT on the BDI scores, i.e. an increased risk of depression with an odds ratio of 1.871 (P = 0.029) for hypo- and hypergonadal men. Also, there was an interaction between BAT and BMI, which was mainly detected in underweight and obese men. This U-shaped effect for underweight and obese men was not detected in men with a 'normal' weight, who had a significantly linear decrease in the risk of depression by changing from the hypogonadal to the eugonadal subgroup, as well as for changing from the eugonadal to the hypergonadal subgroup, with a mean odds ratio of 0.513 (P = 0.032).

CONCLUSIONS

Depression depends on BAT and BMI; in men of normal weight, an increase in BAT reduces the risk of depression, which is not the case in underweight and obese men. Consequently eugonadal men with normal testosterone levels have the lowest risk of depression.

Biochemical reference intervals for sex hormones with a new AutoDelfia method in aged men

BACKGROUND

Our aim was to establish sex hormone reference intervals measured with a new AutoDelfia immunoassay method for aged men free of medication and/or conditions known to influence sex hormone levels.

METHODS

The reference population consisted of 466 individuals between 64 and 97 years (mean 72 years) and a mean body mass index (BMI) of 26.9 kg/m(2).

RESULTS AND CONCLUSIONS

Because age correlated significantly with most sex hormones studied, we calculated reference intervals for three age groups (64-69, 70-74 and > or =75 years). In clinical practice, single ranges can be used for men aged 64 years or over for testosterone, estradiol and follicle-stimulating hormone (FSH) with the AutoDelfia method. For free testosterone and luteinizing hormone (LH), separate reference intervals should be used for men aged 64-74 years and those aged 75 years or over. For sex hormone-binding globulin, two separate reference intervals by age (64-69 and > or =70 years) are also needed for aged men. LH and FSH reference ranges should be judged with caution, because they may be too high due to cases of subclinical hypogonadism included in the reference population.

Hypogonadism in HIV-1-Infected Men is common and does not resolve during antiretroviral therapy

Objectives

To assess the prevalence of abnormal testosterone and gonadotropin values in HIV-infected men before and after 2 years of combination antiretroviral therapy (cART).

Design

Multicentre cohort of HIV-infected adults.

Methods

We identified 139 Caucasian antiretroviral-naive male patients who started zidovudine/ lamivudine-based cART that was virologically successful over a 2 year period. Ninety-seven were randomly chosen and plasma hormone determinations of free testosterone (fT) and luteinizing hormone (LH) at baseline and after 2 years of cART were evaluated.

Results

At baseline 68 patients (70%) had subnormal fT levels. In these, LH levels were low in 44%, normal in 47% and high in 9%. There was a trend for an association between lower CD4+ T-cell counts and hypogonadism. Most participants had normal FSH levels. No significant changes of fT, LH and FSH levels were observed after 2 years of cART.

Conclusions

Low fT levels, mainly with normal or low LH levels and thus indicating secondary hypogonadism, are found in the majority of HIV-infected men and do not resolve during 2 years of successful cART.