Androgen therapy in the aging male

Abstract

The world population is expanding rapidly; at the same time, life expectancy is increasing, and fertility rates are decreasing. Due to these facts, it is expected that the biggest increases of population growth will occur in the aging population. In the aging male, endocrine changes and a decline in endocrine function involve tissue responsiveness as well as reduced secretory output from peripheral glands and alterations in the central mechanism controlling the temporal organization of hormonal release. The latter are likely to be responsible for the dampened circadian hormonal and non-hormonal rhythms. These are in part responsible for the age-dependent decrease of the peripheral levels of testosterone, dehydroepiandrosterone (DHEA), the thyroid hormones, growth hormone (GH), IGF1 and melatonin. These hormonal changes, which develop in most men at about the age of 50, are in part responsible for endocrine deficiencies of some older men. One of the best-studied endocrine deficiencies is late-onset hypogonadism. This is a syndrome characterized by adverse effects on multiple organ systems and decreased quality of life, associated with advancing age and characterized by signs and symptoms of hypogonadism and a deficiency in serum androgen levels with or without a decreased genomic sensitivity to androgens. In cases of endocrine deficiencies, traditional endocrinology aims to replace the missing hormone or hormones with substitutes. It has been demonstrated that interventions such as hormone therapies may favorably influence some of the pathological conditions in aging men by preventing the preventable and delaying the inevitable. A comprehensive medical, psycho-social and life-style history, a physical examination and laboratory testing are essential for the diagnosis and management of late-onset hypogonadism. Acute, chronic or inter-current diseases must be taken into consideration prior to initiating any hormonal substitution therapy. In the era of evidence-based medicine, we have to acknowledge that data on testosterone therapy (HT) in the aging male is mostly circumstantial, based on experience in the treatment of transitional or chronic hypogonadism in young men resulting from disease or experiments of nature. However, over the past several years prospective studies on testosterone therapy in the aging male were performed and shown to be beneficial for certain older men in preventing or delaying some aspects of aging. Recommendations for algorithms for the diagnosis of late-onset hypogonadism and monitoring therapy for safety and efficacy are the subject of this paper.