A few months back I clicked on an article in the Washington Post because of its intriguing headline—“New study highlights the role of testosterone in longevity.” I was hoping to see further evidence in favor of the benefits of testosterone (T) replacement for men that have decreased levels of the hormone. Here’s what I read:
Now, a study that analyzes the longevity of eunuchs, or castrated men, suggests that testosterone may play a part in shortening men’s lives.
Needless to say, that was not what I was expecting.
As a doctor who prescribes testosterone replacement therapy as part of my medical practice, I found this article a tad disturbing. I’m part of a movement that has contributed to a 500 percent rise in T prescriptions over the past 18 years!
The author of the article described a study analyzing data on eunuchs who served the Korean royal court until the late 19th century. Researchers were able to use detailed genealogical records about these men and their adopted male children (also castrates) to determine the impact of castration, which eliminates testosterone entirely, on lifespan. “The eunuchs outlived their uncastrated contemporaries by 14 to 19 years,” the researchers found. Other studies on castrati have found an increase in lifespan in men who lived their whole adult lives without their testicles.
The tradeoff for a longer life? They also had total erectile dysfunction, gained weight, couldn’t build muscle, and had to live their entire lives without enjoying sex. Their risk of type 2 diabetes, obesity and high blood pressure was higher. They probably didn’t have much energy, drive or lust for life, either. The average man might be willing to trade a decade and a half of lifespan to avoid this kind of existence. The good news: he doesn’t have to.
Research shows that testosterone replacement does in fact lengthen both lifespan and healthspan (the healthy, active years within lifespan) when prescribed to treat a lack of this hormone.
It’s sad to say, but most American men die of heart disease. The evidence has been piling up in favor of the positive impact testosterone replacement has on many aspects of heart health for men with decreased levels of T. So-called supraphysiologic levels, or hormone levels beyond normal, do not help prevent heart disease or reduce risk of death.
Current estimates are that 30 percent of American men are affected by hypogonadism—T levels below 300 ng/dL. Average T levels have been dropping in men over the past 20 years. They are about 16 percent lower in men aged 65-69 than they were in 1993. Obesity and environmental toxins are among the suspected causes.
Excess body fat increases the action of aromatase enzymes in men’s bodies. Aromatase transforms testosterone into estrogen, causing a man’s T levels to drop. Environmental toxins may damage men’s testosterone-making machinery, beginning in the very earliest stages of development in the mother’s body.
Here is additional evidence in favor of testosterone replacement therapy:
• Men with heart disease are more likely to have low T. Men with low T are more likely to have heart attacks and experience early death.
• Several studies show that a man’s life expectancy is shorter when his testosterone level is low. Said another way, low serum testosterone predicts earlier death. In one study of 794 men aged 50-91, who researchers followed over a period of 11 years, those with low T were 40 percent more likely to die sooner than those with normal levels.
• Men who undergo hormonal ablation (‘castration’ using powerful hormone-suppressing medications) for prostate cancer have greatly increased risk of heart attack.
• Lack of testosterone seems especially dangerous to men with diabetes or kidney disease. A study of diabetic men found a doubling of death rate in those with low T compared with those with normal T. Twenty percent of the low-T diabetics died within the six years of follow up, compared with 9 percent of men with normal T.
• In a study of dialysis patients, higher blood testosterone levels were associated with much lower risk of death (nearly half the risk of those with lower T).
In my next blog post, I will outline additional benefits of testosterone replacement therapy in men with decreased levels of T.
Endocrine Abstracts 2011;25:P163
• Bello AK, et al, Serum testosterone levels and clinical outcomes in male hemodialysis patients. Am J Kidney Disease 2013 Jul 26.
Photo credit: Riwan