Men and Andropause: Part 2
By NBH, Education Director and CEO of NBH Lifetime Health
Testosterone-the Key to Andropause
In women, estrogen and progesterone are the two key hormones that decline during menopause. In men, it is the hormone testosterone that falls most in production as a man ages, and it’s thought that this fall is the single most important cause of andropause. Testosterone levels peak in a man at approximately age 25 to 30 and then begin a gradual decline. Some men have low testosterone by age 30.
One reason that aging men are not diagnosed as being testosterone deficient is that blood test laboratory reference ranges are age-adjusted to reflect the anticipated reduction in testosterone production. So, when a provider looks at an aging man’s free testosterone blood test result, he often sees it fitting neatly into the standard reference range for a “normal” aging man. The problem is that normal aging men are expected to have lower testosterone levels, which are far from optimal (youthful) ranges. The optimal testosterone level for most aging males are those of a healthy 21-to-30 year old.
Testosterone is vitally important for its anabolic properties, including effects on cholesterol levels, protein breakdown, muscle mass and bone density, and its androgenic effects, including the development and maintenance of male secondary sex characteristics (deep voice, increase in facial and body hair, muscle
How Testosterone Changes in Aging Men
One change found in aging is in the ratio of free testosterone to testosterone bound to SHBG. In many aging men, especially those who are obese, free testosterone levels drop significantly as the levels of SHBG increase and “bind up” whatever free testosterone is left. As if this news isn’t bad enough, there are also steep declines (40% to 75%) in other steroid hormones, including dehydroepiandrosterone (DHEA) and DHEA-sulfate (DHEA-S) seen in men as they age from 20 to 80.
*Testosterone Strengthens Muscles and Bones
One of the most destructive effects of aging is the loss of muscle and bone mass. While the loss of bone mass, or osteoporosis, is now widely recognized as a significant factor in robbing elderly women of their ability to walk, osteoporosis is also a significant health concern for older men. In addition, the loss of muscle tissue, or sarcopenia, is now finally being recognized as a major debilitator of both men and women. In men, both sarcopenia and osteoporosis can be linked to the decline in testosterone and other steroid hormones.
Adequate levels of testosterone are also needed for optimal brain functioning. Multiple studies have confirmed that men who maintain optimal testosterone levels as they age have significantly fewer symptoms of senility compared to men with low levels of testosterone. In a hallmark study published in 2002, 407 men aged 50-to-91 were followed for 10 years and were given multiple tests to determine their testosterone levels and cognitive functioning.
The authors concluded: “Higher FTI [free testosterone levels] was associated with better scores on visual and verbal memory, visuospatial functioning and visuomotor scanning and a reduced rate of longitudinal decline in visual memory.” Furthermore, those randomized, placebo-controlled studies showed that testosterone supplementation improved verbal memory, working memory and visuospatial performance in elderly men.
Declining Testosterone Levels
Declining testosterone levels can lead to the development of numerous symptoms such as a decrease in virility, libido and sexual activity, general sense of well-being, as well as fatigue, depression and sleep disturbances. In addition to problems such as sexual dysfunction or general malaise, low testosterone also translates into decreased muscle mass and strength, as well as a decrease in bone mass and an increase in abdominal fat. Studies show that the latter two pay a role in degenerative diseases such as osteoporosis, cardiovascular disease and diabetes. Moreover, depleted testosterone levels are being linked to the incidence of various lipid disorders and heart disease.
Less Bone, More Fat
While osteoporosis hasn’t always been considered a disease that afflicts males, the rising incidence of bone mass degeneration among aging men points a finger to some age-related cause. As androgen receptors are expressed in osteoblasts (bone-forming cells) researchers now believe that androgens have some direct effect on bone formation and resorption.
Declining Testosterone, Fat Mass and Heart Risk
A growing body of research now suggests that an age-related increase in fat mass, or obesity, can be attributed to a fall in free testosterone and growth hormone replacement levels. Moreover, studies report a connection between abdominal obesity and increased cardiovascular mortality and Type II diabetes mellitus. Recent findings from the University Hospital in Ghent, Belgium illustrate that age is related to a drop in free testosterone levels and free insulin-like growth factor-1, while contributing to an increase in body mass index and fat mass.
One recent study consisting of 372 males aged >20-85, revealed that body mass index and age were independent factors in determining testosterone levels. These decreased by about one quarter when researchers compared the young controls to men in the elderly group, while free testosterone levels fell by almost half with age. Likewise, fat-free mass decreased by 18.9%. In a subgroup of 57 men aged 70-80 years, the lower that testosterone levels dropped, the higher the percentage of body and abdominal fat, as well as plasma insulin levels.
Low Testosterone and Increased Risk of Diabetes and Adipose Fat.
Other findings indicate that low testosterone levels predisposed men to adipose fat which, in turn, seemed to raise their risk of diabetes mellitus. Researchers at the University of Washington’s Department of Medicine set out to examine the effects of age-related decreasing serum testosterone levels on intra-abdominal fat in a group of 110 second-generation healthy Japanese-American men. Measurements were taken first to establish baseline levels of glucose, body mass index, visceral adiposity, subcutaneous fat, fasting insulin and C-peptide levels, and overall testosterone levels (which were within the normal range relative to the men’s age).
When the researchers performed follow-up measurements 7.5 years later, their results indicated that intra-abdominal fat had increased by an average of 8.0 centimeters squared. More importantly, though, they found that the change in intra-abdominal fat correlated to baseline total testosterone levels, but they were not significantly related to other measurements such as body mass index, total fat or subcutaneous fat. The study authors concluded that, in their sample, “lower baseline total testosterone independently predicts an increase in intra-abdominal fat. This would suggest that by predisposing to an increase in visceral adiposity, low levels of testosterone may increase the risk of type II diabetes mellitus.”
Low testosterone Levels, Excess Abdominal Fat and Heart Disease
Similarly, another study that analyzed some of the health effects of excess abdominal fat, also referred to as android obesity, reported that individuals exhibiting upper body excess fat distribution tend to have lower levels of plasma testosterone and growth hormone levels, suggesting what the authors describe as “complex hormonal abnormalities”.
Abdominal obesity lends itself to an apple-shaped figure and has been related to a heightened risk of conditions such as cancer, diabetes and heart disease. These researchers believe that, “Visceral fat tissue, through its portal drainage, could be an important source for free fatty acids that may exert complex metabolic effects: involvement in hepatic lipogenesis, increase in hepatic neoglucogenic flux, reduction in insulin metabolic clearance and involvement in peripheral insulin resistance through a competition mechanism described by Randle.”
They conclude that abdominal obesity may be related to diabetes by means of an enhanced fatty acid made available from fat tissues (visceral and subcutaneous) in individuals who are genetically predisposed to type II diabetes. Research has also pointed to the possibility of a link between abdominal obesity and hypercorticism, or elevated cortisol levels. A reason for this, suggest scientists, might be that excess cortisol opposes testosterone and growth hormone production, both of which are regulators of body fat. Moreover, low testosterone levels also seem to encourage cortisol levels to rise and elicit their many aging effects, including immune dysfunction, brain cell injury, arterial wall damage and other assaults.
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