what's new about low testosterone

Testosterone Replacement is Safe in Older Men with Low Testosterone

June 17, 2008 — In middle-aged and older men with low testosterone levels, testosterone replacement therapy lasting a year or more was safe and caused no evidence of prostate disease, a new study found. The results will be presented at The Endocrine Society’s 90th Annual Meeting in San Francisco.

Prostate cancer is a concern regarding testosterone therapy in elderly men, along with the possibility of blood clots, said study coauthor Farid Saad, PhD, of Bayer Schering Pharma in Berlin. “There is no evidence that testosterone induces prostate cancer, but once a prostate cancer has developed, testosterone treatment will stimulate its growth,” he said.

For these reasons, men receiving testosterone treatment get closer medical surveillance than older men in general, he said. Also, Saad said doctors can adjust the dose to manage the risk of blood clots. Clots may occur because testosterone can overstimulate the formation of red blood cells. Furthermore, in recent years, The Endocrine Society and other organizations developed clinical practice guidelines designed to enhance the responsible and safe use of testosterone treatment in men with low testosterone.

Saad and his co-workers used these guidelines in treating their study subjects, he said. All 95 men in the study (ages 34 to 69 years) were hypogonadal, meaning their body does not produce enough testosterone and symptoms have resulted. Possible symptoms include diminished sex drive, erectile dysfunction, increased fat, and decreased muscle mass.

Patients received hormone replacement that restored testosterone levels to the normal range but did not exceed the upper limit, Saad said. Treatment used a slow-release, injectable form of the hormone (testosterone undecanoate) that is not yet available in the United States. Thirty men had testosterone treatment for 18 months; 51 men, for 15 months; and the remainder, for 12 months.

The researchers measured patients’ prostate volume and prostate-specific antigen (PSA), measures of prostate function. Increased PSA levels may indicate an enlarged prostate, inflammation of the prostate (prostatitis), or prostate cancer. Neither PSA nor prostate volume greatly increased due to testosterone treatment, according to Saad.

The investigators administered a hematocrit blood test to measure the number of red blood cells. Twelve men, all younger than 57, had hematocrit values above normal at some point in treatment, but all returned to normal without intervention, he said. Hemoglobin, a component of red blood cells, increased but not above the upper limit of normal, study data showed.

“If elderly men have a deficiency of testosterone, it is acceptably safe to treat them with testosterone as long as guidelines are followed,” he said. “But longer-term studies are needed.”

Researchers from The Netherlands and Germany collaborated on these studies. Study participants received treatment in a hospital clinic in Bremerhaven, Germany, which provided free care and testosterone through the German social health care system.

Saad is an employee of Bayer Schering, which makes a brand of testosterone undecanoate, and he contributed to the study design.

Low Testosterone Appears to Increase Long-Term Risk of Death

June 17, 2008 — 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.

DPC Biermann, Bad Nauheim, Germany, provided the testosterone reagent, and Novo Nordisc provided partial funding for this analysis.

Testosterone Replacement in Older Men Does Not Increase Risk of Prostate Cancer

June 15, 2008 — Older men who receive testosterone replacement therapy because of low testosterone are no more likely to get prostate cancer than similarly aged men not receiving testosterone, a new study found. The results will be presented at The Endocrine Society’s 90th Annual Meeting in San Francisco.

Prostate cancer is a concern regarding testosterone therapy in older men, said lead author Aksam Yassin, MD, PhD, of the Clinic for Urology and Andrology of the Segeberger Clinics in Norderstedt, Germany. “Testosterone treatment stimulates the growth of an existing prostate cancer, but there is no evidence that it causes this type of cancer,” he said.

The risk of prostate cancer and testosterone deficiency increases with age. Therefore, it is possible that a prostate cancer may occur in an older man during testosterone replacement therapy, which is unrelated to treatment, Yassin said. His research, performed with scientists from Germany and the United Arab Emirates, aimed to determine if prostate cancer occurs more often with testosterone replacement therapy in men over 50.

The study involved 154 testosterone-deficient men with an average age of 56, who had 1 to 3 years of follow-up testing. Patients received testosterone injections in a hospital clinic in Bremerhaven, Germany. Testosterone was a slow-release form called testosterone undecanoate (brand name Nebido) that is not yet available in the United States. The researchers compared these patients with 160 men visiting the clinic for a health checkup who had normal testosterone levels and did not receive testosterone treatment. Their average age was 58.

At the beginning of the study and then every 3 months afterward, all subjects had an evaluation that included a digital rectal exam, ultrasound measurement of prostate volume and a blood test for prostate-specific antigen (PSA). Increased PSA levels may indicate prostate cancer, an enlarged prostate or inflammation of the prostate (prostatitis). If a man’s PSA level was high—over 4 (micrograms per liter)—or otherwise abnormal, he underwent a prostate biopsy.

The rectal exam found no abnormalities. Eleven men receiving testosterone had a biopsy, two of which showed a small cancerous tumor on one side of the prostate. A third man was found to have a high-grade (more aggressively malignant) prostate cancer that had not yet spread to other organs. Of the 12 men in the untreated group, five had prostate cancer. Four of these tumors were on both sides of the prostate and were high grade. Therefore, there were no more prostate cancers in the group that received testosterone treatment, Yassin concluded. Moreover, the men receiving testosterone had smaller, less aggressive tumors than did the other men, he said.

“There is increasing evidence that testosterone replacement therapy in testosterone-deficient men can improve their symptoms, such as decreased bone and muscle mass and low sex drive and depression,” he said. “In view of the many benefits of treatment and the results of our study, we believe it is acceptably safe to treat older men with testosterone if there is a good reason for treatment.”

Yassin is on the speakers’ bureau for Bayer Schering, which makes the brand of testosterone undecenoate used in this study. However, patients received testosterone as a free benefit of the German social health care system, he said.