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      Gonadal Steroids and Body Composition, Strength, and Sexual Function in Men

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          Abstract

          Current approaches to diagnosing testosterone deficiency do not consider the physiological consequences of various testosterone levels or whether deficiencies of testosterone, estradiol, or both account for clinical manifestations. We provided 198 healthy men 20 to 50 years of age with goserelin acetate (to suppress endogenous testosterone and estradiol) and randomly assigned them to receive a placebo gel or 1.25 g, 2.5 g, 5 g, or 10 g of testosterone gel daily for 16 weeks. Another 202 healthy men received goserelin acetate, placebo gel or testosterone gel, and anastrozole (to suppress the conversion of testosterone to estradiol). Changes in the percentage of body fat and in lean mass were the primary outcomes. Subcutaneous- and intraabdominal-fat areas, thigh-muscle area and strength, and sexual function were also assessed. The percentage of body fat increased in groups receiving placebo or 1.25 g or 2.5 g of testosterone daily without anastrozole (mean testosterone level, 44±13 ng per deciliter, 191±78 ng per deciliter, and 337±173 ng per deciliter, respectively). Lean mass and thigh-muscle area decreased in men receiving placebo and in those receiving 1.25 g of testosterone daily without anastrozole. Leg-press strength fell only with placebo administration. In general, sexual desire declined as the testosterone dose was reduced. The amount of testosterone required to maintain lean mass, fat mass, strength, and sexual function varied widely in men. Androgen deficiency accounted for decreases in lean mass, muscle size, and strength; estrogen deficiency primarily accounted for increases in body fat; and both contributed to the decline in sexual function. Our findings support changes in the approach to evaluation and management of hypogonadism in men. (Funded by the National Institutes of Health and others; ClinicalTrials.gov number, NCT00114114.).

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          Most cited references29

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          Age-related changes in total and regional fat distribution.

          Aging is associated with progressive changes in total and regional fat distribution that have negative health consequences. Indeed, a preferential increase in abdominal fat, in particular visceral fat, combined with a decrease in lower body subcutaneous fat are commonly cited in the literature. These age-related changes in body composition can occur independent of changes in total adiposity, body weight or waist circumference, and represent a phenotype closely associated with increased morbidity and mortality risk. Tissues such as the heart, liver and skeletal muscle in the elderly have increased fat deposition, which increases risk for insulin resistance and cardiovascular disease. Furthermore, aging is associated with increased fat content within bone marrow, which exposes the elderly to fracture risk beyond that associated with low bone mineral density alone. Many of the age-associated body compositional changes cannot be detected by simple anthropometric measures alone, and the influence of gender, race or ethnicity, and physical activity patterns on these changes is unclear. This review will explore some of these age-related changes in total and regional fat distribution. Consideration will also be given to the strengths and limitations associated with some of the anthropometric methodologies employed for assessing these changes.
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            Relationship of serum sex steroid levels and bone turnover markers with bone mineral density in men and women: a key role for bioavailable estrogen.

            Estrogen (E) deficiency associated with the menopause is the major cause of bone loss in aging women. However, men also lose significant amounts of bone with age, but they do not have the equivalent of menopause, and serum total testosterone (T) and E levels decline only marginally with age in men. Thus, it has been difficult to attribute bone loss in aging men to either T or E deficiency. Here, we show in a population-based, age-stratified sample of 346 men, aged 23-90 yr, that serum total T and E (estradiol plus estrone) levels decreased over the life span by 30% and 12%, respectively, but bioavailable (or nonsex hormone-binding globulin-bound) T and E levels decreased by 64% and 47%, respectively. In these men and in a parallel cohort of 304 women, aged 21-94 yr, serum PTH increased 84% and 64% over the life span, and urinary N-telopeptide of type I collagen (NTx) excretion, a bone resorption marker, increased 77% and 80% between age 50-85 yr in the men and women, respectively. By univariate analyses, serum bioavailable T and E levels correlated positively with bone mineral density (BMD) at the total body, spine, proximal femur, and distal radius and negatively with urinary NTx excretion in men and women. Urinary NTx excretion was also negatively associated with BMD in both sexes. By multivariate analyses, however, serum bioavailable E level was the consistent independent predictor of BMD in both men and postmenopausal women. Thus, bioavailable E levels decline significantly with age and are important predictors of BMD in men as well as women. These studies suggest that in contrast to traditional belief, age-related bone loss may be the result of E deficiency not just in postmenopausal women, but also in men.
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              Exogenous testosterone (T) alone or with finasteride increases physical performance, grip strength, and lean body mass in older men with low serum T.

              Testosterone (T) therapy in older men with low serum T levels increases lean body mass and decreases fat mass. These changes might improve physical performance and strength; however, it has not been established whether T therapy improves functional outcome in older men. Moreover, concerns exist about the impact of T therapy on the prostate in older men. The administration of finasteride (F), which partially blocks the conversion of T to the more potent androgen, dihydrotestosterone, attenuates the impact of T replacement on prostate size and prostate-specific antigen. We hypothesized that T replacement in older, hypogonadal men would improve physical function and that the addition of F to this regimen would continue to provide the T-induced improvements in physical performance, strength, and body composition. Seventy men with low serum T (<350 ng/dl), age 65 yr and older, were randomly assigned to receive one of three regimens for 36 months: 1) T enanthate, 200 mg im every 2 wk, with placebo pills daily (T-only); 2) T enanthate, 200 mg every 2 wk, with 5 mg F daily (T + F); or 3) placebo injections and pills (placebo). We obtained serial measurements of timed physical performance, grip strength, lower extremity strength, body composition (by dual-energy x-ray absorptiometry), fasting cholesterol profiles, and hormones. Fifty men completed the 36-month protocol. After 36 months, T therapy significantly improved performance in a timed functional test when compared with baseline and placebo [4.3 +/- 1.6% (mean +/- sem, T-only) and 3.8 +/- 1.0% (T + F) vs. -5.6 +/- 1.9% for placebo (P < 0.002 for both T and T + F vs. placebo)] and increased handgrip strength compared with baseline and placebo (P < 0.05). T therapy increased lean body mass [3.77 +/- 0.55 kg (T-only) and 3.64 +/- 0.56 kg (T + F) vs. -0.21 +/- 0.55 kg for placebo (P < 0.0001)], decreased fat mass, and significantly decreased total cholesterol, low-density lipoprotein, and leptin, without affecting high-density lipoprotein, adiponectin, or fasting insulin levels. These results demonstrate that T therapy in older men with low serum T improves physical performance and strength over 36 months, when administered alone or when combined with F, and suggest that high serum levels of dihydrotestosterone are not essential for these beneficial effects of T in men.
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                Author and article information

                Journal
                New England Journal of Medicine
                N Engl J Med
                Massachusetts Medical Society
                0028-4793
                1533-4406
                September 12 2013
                September 12 2013
                : 369
                : 11
                : 1011-1022
                Article
                10.1056/NEJMoa1206168
                4142768
                24024838
                83c58c5f-4699-43dd-973e-ce22e7f53103
                © 2013
                History

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