A mathematical comparison of techniques to predict biologically available testosterone in a cohort of 1072 men

Morris, Paul D; Malkin, CJ; Channer, KS; Jones, T. H.

doi:10.1530/eje.0.1510241

Cited by 110 publications

(82 citation statements)

References 19 publications

(8 reference statements)

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“…Total testosterone, SHBG, LH and FSH and high sensitivity CRP (hsCRP) were measured by ELISA (DRG Instruments GmbH, Marburg, Germany) and fasting lipids (Olympic Diagnostics, Hamburg, Germany). Calculated measurements of free and bioavailable testosterone were made using published formulae (24,25).…”

Section: Study Design and Treatmentmentioning

confidence: 99%

Long-term benefits of testosterone replacement therapy on angina threshold and atheroma in men

Mathur

Malkin²,

Saeed³

et al. 2009

European Journal of Endocrinology

135

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Introduction: In short-term studies, testosterone replacement therapy has been shown to protect male subjects from exercise-induced ischaemia and modify cardiovascular risk factors such as insulin resistance, fat mass and lipid profiles. Methods: This randomised parallel group controlled trial was designed to assess the treatment effect of testosterone therapy (Nebido) compared with placebo in terms of exercise-induced ischaemia, lipid profiles, carotid intima-media thickness (CIMT) and body composition during 12 months treatment in men with low testosterone levels and angina. Results: A total of 15 men were recruited but 13 (nZ13) reached adequate duration of follow-up; seven were treated with testosterone and six with placebo. Testosterone increased time to ischaemia (129G48 s versus 12G18, PZ0.02) and haemoglobin (0.4G0.6 g/dl versus K0.03G0.5, PZ0.04), and reduced body mass index (K0.3 kg/m 2 versus 1.3G1, PZ0.04) and triglycerides (K0.36

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Section: Study Design and Treatmentmentioning

confidence: 99%

Long-term benefits of testosterone replacement therapy on angina threshold and atheroma in men

Mathur

Malkin²,

Saeed³

et al. 2009

European Journal of Endocrinology

135

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“…A calculated free testosterone value less than 5 ng/dl is considered abnormal. When the total testosterone value is borderline, calculated free testosterone values are useful to help confirm androgen insufficiency [105]. In studies using this approach, 17.6% of men with ED had criteria for androgen insufficiency [106].…”

Section: Testosteronementioning

confidence: 99%

Testosterone and Erectile Function: From Basic Research to a New Clinical Paradigm for Managing Men with Androgen Insufficiency and Erectile Dysfunction

2007

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Objectives-Androgens are essential for the development and growth of the penis, and they regulate erectile physiology by multiple mechanisms. Our goal is to provide a concise overview of the basic research and how this knowledge can be translated into a new clinical paradigm for patient management. In addition, this new paradigm may serve as a basis for stimulating constructive debate regarding the use of testosterone in men, and to promote new, innovative basic and clinical research to further understand the underlying mechanisms of androgen action in restoring erectile physiology. Methods-A literature review was performed utilizing the US National Library of Medicine's PubMed database.Results-On the basis of evidence derived from laboratory animal studies and clinical data, we postulate that androgen insufficiency disrupts cellular-signaling pathways and produces pathologic alterations in penile tissues, leading to erectile dysfunction. In this review, we discuss androgendependent cellular, molecular, and physiologic mechanisms modulating erectile function in the animal model, and the implication of this knowledge in testosterone use in the clinical setting to treat erectile dysfunction. The new clinical paradigm incorporates many of the consensed points of view discussed in traditional consensed algorithms exclusively designed for men with androgen insufficiency. There are, however, novel and innovative differences with this new clinical paradigm. This paradigm represents a fresh effort to provide mandatory and optional management strategies for men with both androgen insufficiency and erectile dysfunction. Conclusions-The new clinical paradigm is evidence-based and represents one of the first attempts to address a logical management plan for men with concomitant hormonal and sexual health concerns.

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“…Free and bioavailable T were calculated from the total concentration and the concentration of SHBG using the equations provided by Ly and Handelsman 34 and Morris et al 35 ; these algorithms have been validated in male populations against a reference method. Free T indicates the concentration of T that is not bound to either SHBG or albumin, while bioavailable T includes the free and albumin-bound fractions.…”

Section: Statistical Analysesmentioning

confidence: 99%

Endogenous sex hormones and the risk of prostate cancer: A prospective study

Weiss¹,

Huang²,

Rinaldi

et al. 2008

Intl Journal of Cancer

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Sex steroid hormones influence prostate development and maintenance through their roles in prostate cellular proliferation, differentiation and apoptosis. Although suspected to be involved in prostate carcinogenesis, an association between circulating androgens and prostate cancer has not been clearly established in epidemiologic studies. We conducted a nested case-control study with prospectively collected samples in the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial, to examine associations of prostate cancer with androstenedione (D4-A), testosterone (T), sex hormone-binding globulin (SHBG) and 3a-androstanediol glucuronide (3a-diolG). A total of 727 incident Caucasian prostate cancer cases (age ≥ 65 years, N 5 396) and 889 matched controls were selected for this analysis. Overall, prostate cancer risks were unrelated to serum T, estimated free and bioavailable T, and SHBG; however, risks increased with increasing T:SHBG ratio (p trend 5 0.01), mostly related to risk in older men (≥65 years, p trend 5 0.001), particularly for aggressive disease [highest versus lowest quartile: odds ratio (OR) 2.76, 95% confidence interval (CI) 1. 50-5.09]. No clear patterns were noted for D4-A and 3a-diolG. In summary, our large prospective study did not show convincing evidence of a relationship between serum sex hormones and prostate cancer. T:SHBG ratio was related to risk in this older population of men, but the significance of this ratio in steroidal biology is unclear. ' 2008 Wiley-Liss, Inc.Key words: prostate; hormones; testosterone; 3a-diolG; sex hormonebinding globulin; androstenedione Prostate cancer is the most commonly diagnosed nonskin cancer and the second leading cause of cancer mortality among men in the United States. 1 Age, race and family history of prostate cancer are the only well-established risk factors for this disease (reviewed in Refs. 2, 3). Androgens are important in prostate cancer; prolonged administration of testosterone induces prostate cancer in animal models 4,5 and androgens are important modifiers of disease progression and metastases. 6,7 Testosterone (T) is derived in the testes from androstenedione (D4-A) and is converted in the prostate to its more active form, dihydrotestosterone (DHT). 8 DHT binds in a complex to the androgen receptor (AR), influencing cellular proliferation through control of numerous gene-regulating AR response elements. DHT is further metabolized to 3a-androstanediol (3a-diol) and 3a-androstanediol glucuronide (3a-diolG). In circulation, sex hormone-binding globulin (SHBG) is the major high-affinity carrier of T, while serum albumin serves as an androgen carrier of low binding affinity. 8 SHBG may also play a role directly in steroid signaling, through binding to a receptor (R SHBG ), inducing cAMP synthesis (reviewed in Ref. 9).Although androgens are important in prostate carcinogenesis, 10 epidemiologic studies relating serum hormone levels to prostate cancer risk have been inconclusive, with most prospective studies in the United States an...

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A mathematical comparison of techniques to predict biologically available testosterone in a cohort of 1072 men

Cited by 110 publications

References 19 publications

Long-term benefits of testosterone replacement therapy on angina threshold and atheroma in men

Long-term benefits of testosterone replacement therapy on angina threshold and atheroma in men

Testosterone and Erectile Function: From Basic Research to a New Clinical Paradigm for Managing Men with Androgen Insufficiency and Erectile Dysfunction

Endogenous sex hormones and the risk of prostate cancer: A prospective study

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