Relative testosterone deficiency in older men: clinical definition and presentation

Dysregulation of the Hypothalamic-Pituitary-Testicular Axis due to Energy Deficit

CONTEXT

Although gonadal axis dysregulation from energy deficit is well recognized in women, the effects of energy deficit on the male gonadal axis have received much less attention.

EVIDENCE ACQUISITION

To identify relevant articles, we conducted PubMed searches from inception to May 2021.

EVIDENCE SYNTHESIS

Case series and mechanistic studies demonstrate that energy deficit (both acutely over days or chronically over months) either from inadequate energy intake and/or excessive energy expenditure can lower serum testosterone concentration as a result of hypothalamic-pituitary-testicular (HPT) axis dysregulation in men. The extent to which this has clinical consequences that can be disentangled from the effects of nutritional insufficiency, concomitant endocrine dysregulation (eg, adrenal and thyroid axis), and coexisting comorbidities (eg, depression and substance abuse) is uncertain. HPT axis dysfunction is primarily the result of loss of GnRH pulsatility resulting from a failure of leptin to induce kisspeptin signaling. The roles of neuroendocrine consequences of depression, hypothalamic-pituitary-adrenal axis activation, proinflammatory cytokines, Ghrelin, and genetic susceptibility remain unclear. In contrast to hypogonadism from organic pathology of the HPT axis, energy deficit-associated HPT dysregulation is functional, and generally reversible by restoring energy balance.

CONCLUSIONS

The clinical management of such men should aim to restore adequate nutrition and achieve and maintain a healthy body weight. Psychosocial comorbidities must be identified and addressed. There is no evidence that testosterone treatment is beneficial. Many knowledge gaps regarding epidemiology, pathophysiology, and treatment remain and we highlight several areas that require future research.

Testosterone replacement therapy to improve health in older males

This article provides an overview of current research and updated clinical guidelines regarding testosterone replacement therapy in older males positive for late-onset hypogonadism.

The association of testosterone, sleep, and sexual function in men and women

Testosterone has been the focus of several investigations and review studies in males, but few have addressed its effects on sleep and sexual function, despite evidence of its androgenic effects on circadian activity in both sexes. Studies have been conducted to understand how sleeping increases (and how waking decreases) testosterone levels and how this rhythm can be related to sexual function. This review addresses the inter-relationships among testosterone, sexual function and sleep, including sleep-disordered breathing in both sexes, specifically its effects related to sleep deprivation. In addition, hormonal changes in testosterone that occur in the gonadal and adrenal axis with obstructive sleep apnea and other conditions of chronic sleep deprivation, and which consequently affect sexual life, have also been explored. Nevertheless, hormone-associated sleep disruptions occur across a lifetime, particularly in women. The association between endogenous testosterone and sex, sleep and sleep disturbances is discussed, including the results of clinical trials as well as animal model studies. Evidence of possible pathophysiological mechanisms underlying this relationship is also described. Unraveling the associations of sex steroid hormone concentrations with sleep and sexual function may have clinical implications, as sleep loss reduces testosterone levels in males, and low sex steroid hormone concentrations have been associated with sexual dysfunction.

Considerations for the diagnosis and treatment of testosterone deficiency in elderly men

Increased longevity and population aging will increase the number of men with relative testosterone deficiency, as systemic levels of testosterone decrease by about 1% each year. Androgen deficiency should only be diagnosed in men with definite signs and symptoms, accompanied by low total testosterone levels measured in the morning by a reliable assay. Although clinical trials data are limited, current practice guidelines recommend testosterone replacement therapy for symptomatic men with low testosterone levels to improve bone mineral density, muscle mass and strength, sexual function, and quality of life. Testosterone replacement is not recommended for all older men with low testosterone levels, and should be avoided in patients with prostate or breast cancer, hyperviscosity, erythrocytosis, untreated obstructive sleep apnea, or severe heart failure. The goal of all available testosterone treatment modalities (intramuscular injections, nongenital patch or gel, bioadhesive buccal and oral testosterone, and pellets) is to achieve serum testosterone levels in the mid-normal range during treatment. Cost varies widely among these preparations and may limit their use. Patients receiving testosterone replacement therapy should be re-evaluated 3 months after testosterone initiation and at least annually thereafter.