番茄社区

BOSTON -- Due to low testosterone, male hypogonadism can lead to myriad adverse health outcomes, including osteoporosis and fracture risk.

"Testosterone deficiency is one of the most important causes of male osteoporosis. If the testosterone level becomes critically low, bone mass is lost over time," Dolores Shoback, MD, of the University of California San Francisco, explained to 番茄社区. "Eventually this loss of bone mass and structural deterioration of the bone architecture will weaken the strength of bones and make them susceptible to fractures with minimal trauma."

Along with low hormone levels, this increased risk for osteoporosis is similar to what women experience post-menopause. "Just like estrogen depletion after menopause affects bone health in women, so does hypogonadism in men -- in reality, both are hypogonadal states," said Sudhaker Rao, MD, director of the Bone & Mineral Research Laboratory at Henry Ford Hospital in Detroit.

"However, female hypogonadism -- either natural or after oophorectomy -- is more abrupt than male hypogonadism," he told 番茄社区. "In certain situations even male hypogonadism can be abrupt, such as after castration or after use of medications to deplete or block testosterone level or action, and both affect osteoblast function."

This sentiment was echoed by Shoback, who noted that one of the more common causes of low testosterone levels stems from the use of androgen-deprivation therapy in men with prostate cancer: "Men receiving this form of treatment need to have their skeletal health monitored carefully, as they are at risk for rapid loss of bone mineral density and for fractures, especially for those who are elderly and frail." Preventive measures are key for this group of patients, she said.

Interestingly enough, Rao pointed out, recent studies have suggested that estrogen is also critical for bone health in men, as well as women.

Shoback said it is currently believed that testosterone is converted into estradiol, which is what actually maintains bone mass and strength in men -- not testosterone. "We think that testosterone is the starting material, and that estrogen maintains the bone in adult men."

When it comes to monitoring hypogonadal men with either osteoporosis, unexplained fractures, or height loss, she recommended clinicians measure early morning testosterone levels. "If those are documented to be low, further testing should be done by an endocrinologist to determine the cause for the low testosterone value. Once that evaluation is in progress, the physician can figure out the best treatment for the low testosterone by starting with a bone mineral density assessment." This assessment should be done by a dual-energy x-ray absorptiometry scan in order to measure bone mass at the spine and hip -- two common sites of osteoporotic fractures.

The best treatment first starts with prevention, Shoback continued. Lifestyle modification including eliminating intake of alcohol and tobacco use, and incorporation of regular daily weight-bearing exercises are key for these men.

"Calcium and vitamin D intake through the diet and supplements should also be optimized according to standards established by the Institute of Medicine for men over the age of 50. Nutritional, lifestyle, and dietary interventions are key prevention strategies for managing patients with low bone mass or with osteoporosis, along with consideration for testosterone-replacement therapy [TRT] or another drug treatment for the osteoporosis.

"In addition, if bone mass becomes low enough, therapy with medications like bisphosphonates or denosumab can stop the loss and help to reduce the risk of fragility fractures," she suggested, adding that TRT can also help inhibit further loss of bone mass in hypogonadal men and prevent the development of very low bone mass, thus increasing fracture risk.

Regarding TRT, Rao said that because of its many side effects and the availability of other effective drugs, TRT solely for the purpose of bone health is rarely used. "In general, bone density response to testosterone therapy in men is weaker than bone density response to estrogen in women."

He also pointed out that although the risk of fractures in men is only about one fifth that of the risk in women, mortality after a hip fracture is greater in men than in women.

"I think we are not paying as much attention to bone health in men, especially with our aging population," Rao emphasized.

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