by Janet Casperson, BS, MSN, ANP-C
Testosterone is called the "king of hormones". Unfortunately, many men experience a slow decline in testosterone level as they age.
Testosterone and Baby Boomers
Do you remember Woodstock? We mean the original concert in August 1969, not the copycats. If the answer is yes, then you are probably a baby boomer.
It's been estimated that every single day, ten thousand people turn 50. We are the baby boomers--and the following information is of particular importance to us.
The impact of 220 million Americans in midlife change is just the tip of the iceberg. Testosterone deficiency, like estrogen deficiency in women, affects almost all men as they get older. Testosterone deficiency has been called the male menopause, andropause, the male climacteric, the change of life, or androgen deficiency in the aging male (ADAM). The effects of testosterone deficiency over time include an increase in body fat, decreased muscle mass, decreased bone mass or brittle bones, decreased libido, depression, and even decreased self esteem. The problem is that this looks just like a "grumpy old man" because it's almost impossible to distinguish aging from testosterone deficiency.
We know that after the age of 30, a man may lose up to 2% of testicular testosterone production each year. We also know that 20% to 50% of healthy men between the ages of 50 and 70 and even some at ages 20 to 40 have lower than normal levels of testosterone. This suggests that up to 5% of all men are at risk for a low testosterone status. According to Census Bureau projections, the number of men in the United States between the ages of 40 and 55 will be close to 60 million by the year 2020. This is a potentially large number of men with low testosterone.
Testosterone and its Effects
To understand testosterone deficiency, it's important to understand testosterone. Testosterone is a member of the androgen family of hormones that is found in both men and women. These androgens include both testosterone and its metabolically active byproducts called dihydrotestosterone, which is hormonally active in the prostate and related structures.
Before birth, testosterone was required to create differentiation of the male sex organs, specifically the penis, scrotum and the prostate. These same hormones are responsible for the start of sexual maturity. Testosterone is strongly related to sexual behavior and function, sperm production and to the development of male secondary sexual characteristics. These characteristics include male hair distribution - the chest, abdominal and pubic hair. It's also responsible for the male's deeper voice, the growth spurts and libido.
Testosterone is also required for the maintenance of muscle mass and the decrease of body fat— characterized by the visual of a 20 year-old in-shape man. When testosterone levels drop, body fat levels increase, muscle mass decreases and we begin to develop the abdominal visceral fat that we have talked about in other articles. Visceral fat is responsible for the genesis of many of the pro-inflammatory and pro-thrombotic metabolites that can affect our body and put us at risk for cardiovascular disease. Testosterone is also a necessary hormone for the development of the enzyme that is responsible for the production of nitric oxide (NO), a cellular transmitter that is extremely important for the health of our arteries and endothelial integrity.
Women and Testosterone
Women, as well as men, can have low testosterone and testosterone replacement is important in some women. In women, testosterone deficiency has been strongly associated with female sexual dysfunction, which has become the focus of much of the research in sexual dysfunction. Female sexual dysfunction is as widespread as male sexual dysfunction but has only recently been recognized as a health problem. Sexual function and sexual desire in women are strongly intertwined and it's often difficult to determine which came first, the sexual dysfunction or the loss of sexual desire.
Currently, we divide female sexual dysfunction into four broad categories:
- Low libido or a sexual desire disorder which affects approximately 40% of women is the most common sexual dysfunction. Testosteronereplacement therapy is thought to be most successful in this group of women.
- Arousal disorder or problems with excitement and lubrication. This is thought to be a blood flow problem very similar to erectile dysfunction.
- Failure to achieve an orgasm or anorgasmia is a very common sexual disorder and has been linked to the use of certain types of antidepressants, which are very commonly used in the United States.
- Finally, sexual pain with penetration or dyspareunia is one of the least common disorders and is typically felt to be related to surgical or obstetric injury. We discuss these disorders at length in our Women's Sexuality Center.
Testosterone Isn't Just for Body-Builders
Testosterone use is often associated with the visual of Arnold Schwarzenegger, now California's governor, but previously a muscle-bound body builder who was thought to be the prototypical testosterone user. This could not be farther from the truth. There are many new options available for testosterone replacement therapy for any man or woman who needs replacement. The advent of testosterone gels, which are a convenient way to treat low testosterone in a dose-dependent fashion and mimic the circadian rhythm, has revolutionized the treatment of testosterone deficiency.
Before the advent of testosterone gels and patches, the vast majority of men needing testosterone replacement were treated with parenteral testosterone injections. Testosterone was mixed with a vehicle such as cottonseed oil and injected deep into the muscle. The oil allowed the testosterone to be released slowly and to mimic physiologic levels. The downside to this treatment was that it required injections between one week and one month apart. These were often done in a physician's office although, in some cases, the patient could self-inject after adequate training. Another drawback was the varying levels of testosterone. Testosterone levels went very high at the initial injection creating an almost euphoric state. When the testosterone dropped below the normal levels, patients would often complain of depression and mood changes.
Oral testosterone preparations are also available. However, the preparations that are currently available in the United States are manufactured by a process that requires the liver to remove a certain part of the testosterone molecule to be metabolically active. This process in the liver is very toxic; this type of treatment regimen had a high incidence of liver problems and therefore is not recommended. The only safe and effective oral testosterone preparation, a product called testosterone undeconoate, is expensive and requires multiple daily dosing to obtain a physiological level. It is available in Canada but not in the United States. The important message is that we have multiple excellent testosterone replacement options available and patients have a choice in what replacement method is used.
Before Starting Testosterone Therapy
Before beginning testosterone therapy, a diagnostic workup is performed by your clinician. A careful history and physical is generally recommended. The physical examination should include a careful examination to assess the size and consistency of the testicles and to make sure that there are no testicular lesions that can interfere with testosterone production. Unfortunately for men, a careful prostate examination is a must to assess the size and contour of the prostate and, most importantly, to rule out any prostate nodules, which can be a clue to the presence of prostate cancer. The history includes all the factors that are included in the ADAM questionnaire, which address erectile status, rigidity and the ability to maintain the erection until completion of satisfactory sexual relations. The medical history will also determine factors like diabetes; many men with Type II diabetes have low testosterone levels as a consequence of the hormonal changes from the diabetes. Other diagnostic clues to a low testosterone level include the loss of morning erections, depression, loss of muscle mass and increased visceral body fat.
Normal Testosterone Level
There are a number laboratory tests that can be used to make the diagnosis of hypogonadism, or a low testosterone level. The most commonly available laboratory test is a serum total testosterone level. This is widespread and inexpensive and is understood by most clinicians. Typically, testosterone levels range between 300 mg/dL and 1000 mg/dL. Young men tend to have higher levels; as we age, the level tends to decrease. Many laboratory tests require a specialized laboratory; the choice of specific diagnostic tests should be left to the clinician who is responsible for the treatment.
The diagnosis of testosterone deficiency or hypogonadism is both a clinical and laboratory diagnosis and relates to both the low testosterone that we see in the blood test and in the patient's symptoms. We never treat patients who have an isolated laboratory finding of a low serum total testosterone without associated symptoms.
During Testosterone Therapy
In men and women who choose to proceed with testosterone therapy, close monitoring is very important. The monitoring of testosterone replacement therapy should be undertaken by a well-trained clinician dedicated to the observance of very strict parameters. These parameters have been very well detailed and include measurement of the serum prostate specific antigen (PSA), a complete blood count (CBC), which is a group of blood tests, testosterone levels and sometimes measurement of some of the breakdown products of testosterone such as estradiol. These laboratory tests should be initiated before therapy begins and on regular intervals during the course of therapy.
Certain testosterone preparations can raise the red blood cell count and create a condition known as polycythemia. In polycythemia, the number of red cells in the blood increases, causing the blood to become thick and raising the risk for more problems such as stroke. The treatment for this condition is decreasing the dose of testosterone or stopping it for several weeks and rechecking the blood test. Total testosterone level should also be measured on a regular basis as a guide to the appropriate dose. In certain individuals, we will check an estradiol level, which is particularly important in men who have higher body levels of fat.
If the prostate specific antigen (PSA) is elevated before the introduction of testosterone therapy, a prostate workup should be done by an experienced urologist. If the PSA remains elevated on a repeat blood test, a prostate ultrasound and possible prostate biopsy may be indicated depending on the treating urologist's clinical judgment.
What to Expect as a Result of Testosterone Treatment
Short-term and long-term testosterone treatment has a number of results. A recent study found that after one week of therapy, men noticed improvement in sexual function and sexual motivation. By week four, erections began to be improved. The response seen with testosterone therapy is durable. When the patients were examined at one year, they had not only improved a variety of measurements of their sexual functioning including sexual motivation, sexual desire, improvement in spontaneous erections and an increase in sexual intercourse, but many had also lost significant body fat and increased body muscle mass and bone mineral density. In some individuals, their depression improved to the point that they did not need concomitant treatment with antidepressants. Any changes in medications such as antidepressants should only be undertaken after consulting your primary care physician.
Testosterone therapy is a valuable option in the treatment of both male and female sexual dysfunction but it requires a careful diagnosis, monitoring and a good relationship with your clinician. Each treatment option is individualized according to the patient's preference. Sometimes the choice of the testosterone preparation is based on financial considerations. Some men and women prefer gels where some prefer injections. The older testosterone injection treatment is the most cost effective and while injection treatments have the inherent problems we previously discussed, this testosterone treatment is better than none at all.
There is much new research in testosterone replacement therapy as it becomes more popular with the baby boomers and as we understand more about the significant positive effects of treatment. The newer preparations include long acting injectable medications that last up to three months. This compound is widely available in Europe and is currently undergoing clinical trials in the United States.
The tremendous benefits of testosterone on the cardiovascular system were shown in recent studies performed in Europe. It has been suggested that there are testosterone receptors on certain cells on the heart and that these can actually be protective in preventing cardiovascular events. There have also been long-term prostate cancer studies. Men who had their testicles removed, creating an instant condition of no testosterone, were shown to be at greater risk for cardiovascular disease. Men who had long-term androgen deprivation therapy for prostate cancer had an increase in their insulin resistance, increasing their risk of cardiovascular disease.
Low testosterone has also been linked to a number of clinical conditions including the development of prostate cancer and Alzheimer's disease as testosterone has been reported to have a positive effect on the memory, mood and function of the brain in men. Another significant risk factor seen with low testosterone is osteoporosis or brittle bones. When a man is seen with a testosterone level less than 200, we believe it's an absolute indication to proceed with DEXA bone testing to rule out the presence of metabolic bone disorders. A stress fracture in a man, especially at a young age, should always prompt a workup for a low testosterone state. A particularly useful method to look for bone loss or osteoporosis in men is measuring height over time and comparing measurements with the loss of height seen with the aging process.
Overall, testosterone plays a central role in the diagnosis and treatment of erectile dysfunction and female sexual dysfunction. There are newer testosterone replacement alternatives currently under study. We predict that testosterone replacement therapy will be essential to the future of maintenance of sexual health status and promoting cardiovascular care.
References: See Bibliography
August 2006
Posted August 2008
Updated August 2009
