Testicular Failure In recent years, there has been increasing interest in the study of aging males. Testicular failure increases with age as serum testosterone levels gradually decline. This process is not universal. When it does occur, there is significant variability in the age at the onset and the degree of the androgen decline associated with age.
Androgen Deficiency The estimated prevalence of androgen deficiency among men 40–70 years of age ranges from 12% to 45%. Approximately 481,000 new cases of androgen deficiency are diagnosed yearly in the USA.
Physiologic levels of testosterone support several critical processes involved in penile erectile response, including the maintenance of libido and energy levels, in addition to the cascade of events mediated by nitric oxide leading to arteriolar dilatation and relaxation. Screening for hypogonadism in men initially presenting with ED can help identify these men. Drug-Induced ED Erectile dysfunction is a common adverse effect of a number of drugs, and it often has a great effect on patient compliance.
This subject as a risk factor is lightly discussed here and further discussed in more detail later in the textbook. It is important to recognize that many of the drugs associated with ED are used to treat conditions that are themselves risk factors for ED, thus the interpretation of ED in the setting of pharmacological therapy is often difficult in the clinical setting.