New research demonstrates the important role that male hormones, such as testosterone, play in men's health.

Four new studies on the role of these hormones in several important areas of men's health, such as osteoporosis, diabetes and sleep disorders, were presented during ENDO 2004, the 86th Annual Meeting of The Endocrine Society, which is taking place in New Orleans.

In addition to the new research, results of a new national poll on men's health, which was co-sponsored by The Endocrine Society along with Research America and Parade Magazine were also announced. The poll's findings shed light on men's perceptions of healthcare, medical research and health issues affecting men, such as infertility.

In recent years, much attention has been given to the important role that hormones, such as estrogen, play in women's health as they age. However, new findings indicate that hormones also positively and negatively impact the health of men. The new studies identify a new bone therapy to reduce the impact of hormone deprivation treatment in men with prostate cancer and also identify low hormone levels in men with specific health conditions.

Treatments to reduce hormone levels, called androgen deprivation therapy (ADT), in men with prostate cancer often decrease bone mineral density (BMD) and increase the risk of fracture. However, new research shows that risedronate, a bisphosphate that is used to treat osteoporosis, lessens bone loss in men with prostate cancer who are undergoing ADT.

Dr. Kazuhiro Ishizaka and colleagues in Japan treated 44 prostate cancer patients between the ages of 72 and 84 with risedronate for six months. They measured the percent change in BMD from the beginning to the end of the study using the femoral neck and lumbar spine. Additionally, the Urinary N-telopeptide was measured to determine bone resorption.

"We found that bone mineral density was maintained in the neck and significantly increased in the spine in the subjects while taking risedronate," explained Dr. Ishizaka. "The men also experienced less bone loss while taking risedronate. These findings highlight the possible benefits of using a bisphosponate, such as risedronate, to counteract the negative effects of prostate cancer treatment in men."

Men with type 2 diabetes should have their testosterone levels measured routinely, as this group has a higher than expected frequency of testosterone deficiency, according to another research presented at ENDO 2004. Dr. T. Hugh Jones and his colleagues in Barnsley, UK evaluated 300 men over the age of 30 who had type 2 diabetes to determine the prevalence of low testosterone levels, and symptomatic hypogonadism.

Seventeen per cent of the men with type 2 diabetes had very low levels of testosterone and another 32 per cent had low normal levels.

"Low testosterone is associated with health conditions such as hypertension obesity, osteoporosis and heart disease. Our results confirm that testosterone status should be evaluated and patients, if clinically indicated, treated with testosterone replacement therapy," explained Dr. Jones.

The authors note that their findings emphasize the issue that many physicians do not regularly check testosterone levels in diabetic men. They add that testosterone levels could play a role in the degree of insulin sensitivity in diabetic men, but it is still uncertain whether testosterone levels contribute to impaired glucose tolerance. Future studies are being planned to examine these areas.

Researchers have also discovered that differences in androgen sensitivity can cause variations in testosterone levels in healthy men. These findings could help doctors understand the underlying mechanisms that cause different "normal" testosterone levels in men.

Dr. Jean Kaufman and researchers at Ghent University Hospital in Belgium measured morning testosterone levels in more than 2,300 men between the ages of 35 and 59. The researchers then compared levels of luteinizing hormone (LH) and Sex hormone-binding globulin (SHBG), which is a glycoprotein synthesized by the liver that can decrease due to high testosterone, in the 200 men with the lowest and highest testosterone levels and also calculated from the testosterone and LH levels, an "androgen sensitivity index."

Dr. Kaufman and his team found higher levels of LH and SHBG in the men with high levels of testosterone compared with men who had low levels of testosterone.

"Our findings indicate, for the first time, that men with high testosterone levels have a lower androgen sensitivity," notes Dr. Kaufman. "This information supports the idea that variations in testosterone levels in normal, healthy men reflects differences in androgen sensitivity," he added.

Of note, these findings identify a new association between clinical and biochemical variables in testosterone levels among healthy men.

German researchers have found a link between low testosterone levels in men and sleep apnoe syndrome, a common sleep disorder that causes the airway to be blocked. However, the same researchers found that an airway treatment, called continuous positive airway pressure (cpap), can improve the condition.

Dr. Walter Reinhardt and colleagues at the University Clinic in Herne Germany studied testosterone, SHBG and LH levels in 45 men with different levels of sleep apnoe syndrome (SAS) four weeks and then six months after beginning treatment with cpap.

Low testosterone levels were found in the SAS patients. However, the cpap treatment significantly improved the men's sleep, with more REM episodes, and increased testosterone levels.

"With low testosterone levels putting men at risk for other health conditions, our results indicate the need to test testosterone levels in men with sleep apnoe syndrome. Additionally, we have shown that cpap treatment can not only improve the sleep of these men, but can also increase the testosterone levels," said Dr. Reinhardt.