In older men with low testosterone levels, testosterone replacement therapy improves their risk factors for cardiovascular disease and diabetes, according to two new studies. The results will be presented at The Endocrine Society's 90th Annual Meeting in San Francisco.
Testosterone deficiency becomes more common with age, occurring in 18 percent of 70-year-olds, said a coauthor of both studies, Farid Saad, PhD, of Berlin-headquartered Bayer Schering Pharma. Low testosterone levels are linked to the metabolic syndrome—a cluster of metabolic risk factors that increase the chances of developing heart disease, stroke, and type 2 diabetes—and other health problems, including loss of bone and muscle mass, depression, and decreased libido.
Yet the risks and benefits of hormone replacement therapy are unclear in older men, he said.
Saad's research showed that restoring testosterone to normal levels in hypogonadal, or testosterone-deficient, men led to major and progressive improvements in features of the metabolic syndrome. Furthermore, men older than 63 benefited as much as younger men, they found. Treatment lasted a year and used a slow-release, injectable form of the hormone (testosterone undecanoate) that is not yet available in the United States.
All the men in this study have the metabolic syndrome that is correlated with high risk of heart disease and other diseases related to problems with the cardiovascular system. So if you do not have the metabolic syndrome these results do not mean that testosterone replacement will help you. It might not help you even if you do have metabolic syndrome.
All 95 men in the studies (ages 34 to 69 years) had the metabolic syndrome. To receive this diagnosis, patients must have three of the following five risk factors: increased waist circumference (abdominal fat), low HDL ("good") cholesterol, high triglycerides (fats in the blood), high blood pressure, and high blood sugar.
The testosterone improved an assortment of markers.
The first study showed that testosterone treatment significantly reduced waist circumference, total cholesterol, LDL ("bad") cholesterol, triglycerides, and body mass index (a measure of body fat). Treatment also increased "good" cholesterol. Improvements were progressive over 12 months, indicating that benefits may continue past a year, Saad said.
In the second study, the researchers divided the patient population into three groups by age: less than 57 years, 57 to 63 years, and more than 63 years. They found that the oldest men had similar improvements in metabolic risk factors to the youngest men.
Additionally, the investigators looked at the degree of testosterone deficiency before treatment. This beginning level of testosterone deficiency did not predict the beneficial outcome, they found. Men whose subnormal testosterone levels were not as low as the others had similar improvements in metabolic risk factors to men with the lowest levels, according to Saad.
"We conclude that if elderly men have a deficiency of testosterone, it is worthwhile to treat them with testosterone," he said.
What I wonder: If testosterone replacement is so beneficial why is it necessary in the first place?
My worry is that testosterone might drop in order to reduce the risk of prostate cancer and perhaps other cancers and diseases. One of the reasons various aspects of metabolism get turned down as we get older is probably an evolutionarily selected for risk reduction against cancer. Cells that divide less often are less prone to becoming cancerous because each cell division runs the risk of a mutation that makes the cell divide out of control.
But it is possible that medical researchers will be able to identify subsets of the population which could see a net decrease in mortality risk from a hormone replacement therapy. A more precise and custom tuning of metabolic function based on a scientific method of assessing the sizes of various risks for each person might turn up people who can benefit from testosterone replacement or some other hormone replacement. Not saying this is possible now. But it might become possible later.
A German study finds that men with lower testosterone have a greater risk of dying. But note this study does not demonstrate the direction of cause and effect. Maybe illness and faster aging lower the testosterone levels and that faster aging might precede the lowering of testosterone.
Men may not live as long if they have low testosterone, regardless of their age, according to a new study. The results will be presented at The Endocrine Society's 90th Annual Meeting in San Francisco.
The new study, from Germany, adds to the scientific evidence linking deficiency of this sex hormone with increased death from all causes over time—so-called "all-cause mortality."
The results should serve as a warning for men with low testosterone to have a healthier lifestyle, including weight control, regular exercise and a healthy diet, said lead author Robin Haring, a PhD student from Ernst-Moritz-Arndt University of Greifswald, Institute for Community Medicine.
"It is very possible that lifestyle determines levels of testosterone," he said.
In the study, Haring and co-workers looked at death from any cause in nearly 2,000 men aged 20 to 79 years who were living in northeast Germany and who participated in the Study of Health in Pomerania (SHIP). Follow-up averaged 7 years. At the beginning of the study, 5 percent of these men had low blood testosterone levels, defined as the lower end of the normal range for young adult men. The men with low testosterone were older, more obese, and had a greater prevalence of diabetes and high blood pressure, compared with men who had higher testosterone levels, Haring said.
Men with low testosterone levels had more than 2.5 times greater risk of dying during the next 10 years compared to men with higher testosterone, the study found. This difference was not explained by age, smoking, alcohol intake, level of physical activity, or increased waist circumference (a risk factor for diabetes and heart disease), Haring said.
In cause-specific death analyses, low testosterone predicted increased risk of death due to cardiovascular disease and cancer but not death of any other single cause.
The fact that low testosterone levels are linked not only to cardiovascular but also to cancer is very interesting. Does testosterone strengthen the immune system to beat down cancer at an early stage? What would explain this result?
|Share |||Randall Parker, 2008 June 17 10:05 PM Aging Treatment Studies|