Health News

Osteoporosis: Not Just a Female Problem

Nov. 23, 1999 (Los Angeles) -- Usually considered a disease of women, osteoporosis may afflict as many two million men, says the author of a commentary in the Journal of Clinical Endocrinology & Metabolism. If fractures are used as evidence of osteoporosis, a man's lifetime risk ranges from 13% to 25%.

"This state of affairs is reminiscent of a decade ago when heart disease was considered to be primarily a disorder of males," writes John P. Bilezikian, MD, of the College of Physicians and Surgeons, Columbia University, New York. Most osteoporosis research has been conducted in women, with symptoms and risk factors presumed to be similar in men. But clinicians now know that osteoporosis in men differs in several important ways.

Although the absolute numbers are high, fewer men than women develop osteoporosis for several reasons, Bilezikian points out. Their bones tend to be larger and they acquire greater bone mass at their peak. Peak bone mass is a major determinant of osteoporosis risk, because that provides the reserve the body draws upon as aging and other forces erode the skeleton. Also, men do not lose as much bone mass as women during middle age because they have no equivalent of menopause.

Estrogen appears to play a key role in the establishment of peak bone mass, so when estrogen levels decline after menopause, a woman's risk of osteoporosis rises. Bilezikian cites cases of men with rare genetic disorders that left them with normal levels of male hormones, called androgens, but deficient in estrogen. They developed osteoporosis. He suggests that "more subtle deficiencies in estrogen action or presence could predispose some men to suboptimal achievement of peak bone mass," thus raising their risk of developing osteoporosis.

However, "one problem is that by measuring blood estrogen levels, we get only a very superficial glimpse, because [male and female hormones are metabolized] at different rates in different tissue," says Eric Orwoll, MD, professor of medicine at Oregon Health Sciences University in Portland. In an interview seeking objective comment, Orwoll tells WebMD that "there is much speculation" about the exact roles played by androgens and estrogens in the development of osteoporosis, but there is "no good way of measuring [the levels of these hormones] in bone. ... This issue is now in the forefront," he says. "We are just beginning to understand it."

Bilezikian estimates that 40-50% of all cases of male osteoporosis are due to alcohol abuse, an excess of hormones called glucocorticoids, or low levels of estrogen. However, that still means that in approximately half of the men with osteoperosis, no definite cause will be found. Doctors call this condition "idiopathic osteoporosis," which means the cause of the condition is unknown. However, after age 70, most cases of osteoporosis in men can be accounted for by aging.

Men with idiopathic osteoporosis usually present with a fracture or back pain. This presentation is different from women who often have no symptoms and are diagnosed by bone mass calculations. Once the diagnosis is made, writes Bilezikian, "all reasonable potential causes of bone loss should be considered." If the cause is known, specific measures should be taken to correct the underlying disorder. If the condition truly is idiopathic, men should be managed like women with osteoporosis: with high calcium intake (1,200 to 1,500 mg/d); adequate vitamin D; exercise, including weight training; limited alcohol intake; and smoking cessation. Research is just beginning on drugs that prevent bones from losing calcium, although one agent, called alendronate (Fosamax), is expected to be effective and should be available soon for use in men. "We just reported a large study of alendronate in men with idiopathic osteoporosis, and it looks like it helps," says Orwoll.