Commonly, the post-menopausal woman is not called hypogonadal if she is of typical menopausal age. If hypogonadism is caused by a disorder of the central nervous system (e.g., a brain tumor), then this is known as central hypogonadism. Women with hypogonadism do not begin menstruating and it may affect their height and breast development. Hypogonadism can involve just hormone production or just fertility, but most commonly involves both.citation needed There are many possible types of hypogonadism and several ways to categorize them. Sperm development (spermatogenesis) and release of the egg from the ovaries (ovulation) may be impaired by hypogonadism, which, depending on the degree of severity, may result in partial or complete infertility. Hypogonadism means diminished functional activity of the gonads—the testicles or the ovaries—that may result in diminished production of sex hormones.
Data from the MMAS have demonstrated that there is a strong, positive relationship between HDL and testosterone in men with cardiovascular disease (low total or free testosterone correlates with low HDL cholesterol) (31). The relationship between testosterone and HDL is confounded by the fact that both HDL and testosterone are inversely related to BMI. However, when given as a transdermal gel to hypogonadal men, there is either no significant change or only minor changes in HDL levels (28,31,32). Vascular tissue (including endothelium and vascular smooth muscle cells) contains androgen receptors, so it is to be expected that testosterone (or its metabolite, oestrogen) is likely to affect the cardiovascular system. There appears to be no consistent evidence that the prevalence of hypogonadism differs between racial and ethnic groups (24–26). An interesting observation from the MMAS was that half of the men found to have symptomatic androgen deficiency at one stage were found to be eugonadal when retested at a later stage (22).
LH acts on the interstitial Leydig cells of the testes, stimulating them to produce testosterone, whereas FSH stimulates spermatogenesis and Sertoli cell function (6,7). The regulation of testosterone production in eugonadal men depends on the HPG axis depicted in Figure 1. For 100 years, the Endocrine Society has been at the forefront of hormone science and public health. 1.2 We recommend against routine screening of men in the general population for hypogonadism.
HIV patients with AIDS are younger and therefore, comparisons have to be carried out with appropriately age-matched controls. While these prevalence levels may superficially appear similar to the background figures in the population, most studies are based on middle-aged populations. The mechanism for OPIAD is thought to involve suppression of GnRH release by the hypothalamus, thereby inducing secondary hypogonadism (17,70). In a case–control study of 40 cancer survivors it was found that 90% of those on opioid treatment were hypogonadal compared with only 40% of the control group (69). Various epidemiological studies in men have examined associations between testosterone and estradiol levels and BMD.
Low levels of testosterone can occur due to disease of the testes or from conditions affecting the hypothalamus or pituitary gland. It is particularly indicated in men with hypogonadism who wish to retain their fertility, as it does not suppress spermatogenesis (sperm production) as testosterone replacement therapy does.citation needed Finally, some physicians worry that obstructive sleep apnea may worsen with testosterone therapy, and should be monitored. Side effects can include an elevation of hematocrit to levels that require blood withdrawal (phlebotomy) to prevent complications from excessively thick blood. In short- and medium-term testosterone replacement therapy the risk of cardiovascular events (including strokes and heart attacks and other heart diseases) is not increased. Screening males who do not have symptoms of hypogonadism is not recommended as of 2018.
However, there is a lot of research in progress to find out more about the effects of testosterone in older men and also whether the use of testosterone replacement therapy would have any benefits. Patients generally see an improvement in their sex drive and self-esteem following testosterone replacement therapy. Symptoms of male hypogonadism, such as lack of sex drive, inadequate erections (erectile dysfunction) and infertility, can lead to low self-esteem and cause depression. Regular blood tests should be carried out during treatment to check for an increase in red blood cells.
Tablet forms of testosterone taken by mouth are not recommended due to a link with liver damage, and because it is more difficult to monitor replacement. Exact treatment will vary between patients and be tailored to their individual needs. In patients with obesity and type 2 diabetes, SHBG is often low which can make the testosterone level appear lower than it really is. In particular, it is important to find out if virilisation (development of normal male characteristics) was complete at birth, whether the testes descended and to see if the patient went through puberty at the same time as his peers. There are genetic causes of hypogonadism, which include Klinefelter’s syndrome and Kallmann’s syndrome; however, these conditions occur sporadically, they are not inherited from the parents. It has been estimated that 8.4% of men aged 50–79 years have testosterone deficiency.