Diagnosing and Managing Low Serum Testosterone

Abstract

Measuring testosterone levels became easier in the 1970s, and it wasn't long before levels were being checked in men across all age groups. At that time, several authors reported an age-associated decline of serum testosterone levels beginning in the fourth or fifth decades of life. Other studies found that the decline in testosterone with age might be more related to comorbidities that develop in many aging men. Aggressive marketing campaigns by pharmaceutical companies have led to increased awareness of this topic, and primary care physicians are seeing more patients who are concerned about "low T." Unfortunately, testosterone replacement therapy has not been straightforward. Many men with low testosterone levels have no symptoms, and many men with symptoms who receive treatment and reach goal testosterone levels have no improvement in their symptoms. The actual prevalence of hypogonadism has been estimated to be 39% in men aged 45 years or older presenting to primary care offices in the United States. As the US population ages, this number is likely to increase. This article, targeted to primary care physicians, reviews the concept of late-onset hypogonadism, describes how to determine the patients who might benefit from therapy, and offers recommendations regarding the workup and initiation of treatment.A 56-year-old overweight man with symptoms of low energy, daytime sleepiness, and decreased libido happens to be watching a golf tournament on TV from his favorite recliner and suddenly a commercial appears. Th is patient is in your offi ce the following Monday and asks you, "Is it low T?"Aggressive marketing campaigns by pharmaceutical companies have led to increased awareness of hypogonadism among men, who may then present to the clinic requesting testing or treatment (1). As a result, primary care physicians are seeing more patients like the one described above. Th e physiological age-related decrease in testosterone production should be differentiated from late-onset hypogonadism (LOH), defi ned as the presence of three sexual symptoms and low testosterone (low T) in aging men (2). Th is defi nition was proposed to help clinicians identify aging men with low testosterone who could potentially benefi t from hormonal replacement therapy. Th e purpose of this article is to review the data on LOH, also known as low T, and present the most recent evidence and recommendations regarding the approach to the patient from our case scenario. PHYSIOLOGY AND DEFINITIONSMale reproductive endocrine physiology involves the hypothalamic-pituitary-target organ and feedback model. Disruptions at diff erent levels of this pathway can lead to disturbed androgenic eff ects: primary disorders of the testes (primary hypogonadism), disorders of the pituitary or hypothalamus (secondary hypogonadism), and disorders of androgen action on target tissue or androgen resistance. Other less common entities that manifest as androgen defi ciency include chronic stress (by suppressing gonadotropin-releasing hormone secretion) and exogenous...

Analysis of cardiovascular risk factors associated with serum testosterone levels according to the US 2011–2012 National Health and Nutrition Examination Survey

“…moderate related work activity ¼ 4 and vigorous related work activity ¼ 8). Testosterone deficiency (TD) was defined as a serum testosterone level <300 ng/dL (10.4 nmol/L) [33,34] after excluding any external factors such as a history of receiving testosterone, history of drug abuse, AIDS, pituitary hypothalamus disease, hyperthyroidism, endstage renal disease or a history of using anti-epilepsy medicine or a 5a-reductase inhibitor. These variables, regardless of being continuous or dichotomous, were included in the logit model of logistic regression, in which the log odds of the outcomes were modeled as a combination of the predictor variables.…”

The Effect of Testosterone and Fenofibrate, Administered Alone or in Combination, on Cardiometabolic Risk Factors in Men with Late‐Onset Hypogonadism and Atherogenic Dyslipidemia

“…In numerous studies, testosterone replacement was able to improve libido, sexual function, central obesity, glycometabolic control, mood, and muscle strength [8,10,11]. Unfortunately, no previous study has investigated the effect of testosterone therapy on cardiovascular morbidity or mortality, and therefore, the causality of the relationship between low testosterone levels and cardiovascular disease is unclear.…”

Predictive Values of Nocturia and Its Voiding Frequency on the Aging Males’ Symptoms

“…For instance, nocturia should be precisely measured by using the frequency volume chart (FVC) over a 2–3-day period [ 35 ]. Moreover, serum testosterone [ 36 ] and melatonin [ 37 ] levels should also be included in the predictive model to represent the modulating effects of androgen deficiency and sleep disruption, respectively. More in-depth investigations using cohort studies and interventional designs for further understanding of the underlying pathology on how nocturia and AMS are related to aging are warranted.…”