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Weak Bones Among Men Are Linked to Estrogen December 8, 1998: New research is challenging the medical textbook view of osteoporosis as largely a women's disease linked to the singularly female experience of menopause. It now seems that osteoporosis is more prevalent in men than was previously thought, and that although men do not go through menopause, the main cause of the degenerative bone disorder is the same in men and women: an age-related drop in estrogen. Several recent studies show that men's levels of this sex hormone decline with age and that the decline leads to a loss of bone mass, the signature symptom of osteoporosis. Some of these studies were presented last week at a meeting of the American Society for Bone and Mineral Research and the International Bone and Mineral Society in San Francisco. "This is surprising," said Dr. B. Lawrence Riggs, a professor of medical research at the Mayo Clinic in Rochester, Minn., who has found that estrogen naturally falls in men after about age 65. "Three years ago, none of us would have thought that estrogen loss was a factor in male osteoporosis." Although men and women have estrogen, it is more abundant in women and plays a central role in female reproduction. The National Osteoporosis Foundation in Washington estimates that of the 10 million Americans who have osteoporosis, more than 1.5 million are men, and that half of women and one in eight men over 50 will have an osteoporosis-related fracture. But because osteoporosis is underdiagnosed in men, the numbers for men are probably higher, the organization's literature says. Medical textbooks describe osteoporosis differently for men and for women. In women it is linked mainly to the sharp drop in estrogen after menopause, because estrogen is known to slow the natural process of bone loss that occurs with age. In men, however, osteoporosis is said to result from abnormally low levels of testosterone, a sex hormone more plentiful in males. The cause of low testosterone is usually a rare condition called hypogonadism, in which the testicles are underactive. Two studies presented at last week's meeting indicate that estrogen plays a more central role than testosterone in osteoporosis in men. Researchers following residents of Framingham, Mass., over five decades studied 382 elderly white men for eight years, tracking bone density, estrogen levels and signs of hypogonadism. Men with the highest bone density also had the highest estrogen levels; the connection with hypogonadism was negligible. In another study, doctors in Germany measured bone density as well as estrogen and testosterone levels of 300 men with osteoporosis for five years. Forty percent of the men had low estrogen; 20 percent had low testosterone. "We didn't see a pronounced effect of testosterone on the males' bone-mineral density," said Dr. Peter Kaps, an orthopedic surgeon and the lead author. Dr. Pamela Taxel, assistant professor of medicine at the University of Connecticut Health Center in Farmington, said: "These are suggestive findings, but larger studies are needed to understand the mechanism of estrogen and testosterone on bone health in men." Dr. Taxel is studying the use of estrogen supplements to treat men with osteoporosis. She said research was needed to develop a form of estrogen that helps men without causing side effects like prostate disease or impotence. By SUSAN GILBERT Copyright 1998 The New York Times Company janet paterson - 51 now /41 dx /37 onset - almonte/ontario/canada [log in to unmask]