Menopause for middle-aged men
Estrogen causes middle-aged men to experience changes in body composition and sexual function in a way similar to how women go through menopause, according to a new study.
The new study, published in The New England Journal of Medicine, built upon evidence that a relatively small proportion of testosterone in men is converted into estrogen and that men with more testosterone end up with more testosterone converted into estrogen.
Scientists have conducted previous studies on low testosterone levels in men can cause adverse physical symptoms. Researchers of this study, from Massachusetts General Hospital (MGH), aimed to determine what levels of testosterone and estrogen corresponded with what physical changes.
Participants included 150 men ages 20 to 50, who were divided into two groups. The first group was given daily doses of testosterone (or a placebo) for four months. The second group was given the same testosterone doses but was also given a substance that prevents testosterone from being converted into estrogen.
Findings showed that in the men whose estrogen production was not blocked, varying levels of testosterone respectively corresponded with decreased sexual desire, erectile dysfunction and reduced lean body mass, muscle size and strength.
Men whose estrogen production was blocked showed increased fat and adverse changes in sexual function regardless of testosterone dosage levels.
Results suggest that the decline in estrogen levels can be the exclusive cause of some symptoms, such as weight gain or erectile dysfunction, and that these symptoms aren’t caused by testosterone deficiency alone.
Findings provide insight into the relationship between specific testosterone levels and the decline of physiological functions, which can help researchers determine which men should be treated with testosterone supplements. More significantly, researchers said this study shows that the forms of testosterone used for therapy should be capable of being converted into estrogen.
However, further studies should be conducted to find out how testosterone replacement therapy could affect prostate cancer and prostate enlargement that causes unpleasant symptoms in many older men, researchers said.