MONDAY, April 7, 2008 (HealthDay News) -- Injections of testosterone appear to improve bone density and reduce bone loss in older men who have low testosterone levels and may help to prevent osteoporosis, a new study suggests.
Testosterone therapy has been used to improve bone strength and muscle mass in some men. However, the hormone treatment is controversial, because it has been associated with increasing the risk of prostate cancer and high levels of red blood cells. And other potential effects of long-term use of testosterone therapy aren't known.
"These preliminary data show beneficial effects of testosterone therapy on bone turnover markers in older men with low-to-normal testosterone concentrations using both continuous and monthly cycled testosterone replacement," lead researcher E. Lichar Dillon, of the Department of Internal Medicine at the University of Texas Medical Branch in Galveston, said in a prepared statement. "The effects of sex hormones on markers of bone formation are complex, but this is an important step in understanding how the process works."
Preliminary study results were expected to be presented April 7 at the American Physiological Society's annual meeting, during the Experimental Biology 2008 conference, in San Diego.
For the study, Dillon's team studied 13 men, ranging in age from 60 to 85. During the five-month trial, the men were either given weekly injections of testosterone, weekly injections of testosterone every other month, or a placebo.
The researchers found that men receiving testosterone had reduced bone turnover, compared with men on a placebo. While the effects of testosterone therapy over the long term aren't clear, the researchers said they believed the treatment would be beneficial by preserving bone mass and preventing osteoporosis.
One expert said the study was too small to prove or disprove the value of testosterone therapy in preventing bone loss and, perhaps, preventing osteoporosis.
"This small, short-term study indicates that men with low levels of testosterone respond to appropriate replacement as far as turnover markers indicate," said John Eisman, director of the Bone and Mineral Research Program at the Garvan Institute of Medical Research, in Sydney, Australia.
While calling the study "too small and too short to provide any insight into fracture-risk reduction or safety outcomes," Eisman said it does complement research he has done. "Our study showed that men with testosterone in the lowest quartile of the population had much higher risk of osteoporotic fractures," he said.
A large, long-term trial testing whether testosterone can prevent osteoporosis in men is needed to settle the question, Eisman said.
To learn more about men and osteoporosis, visit the U.S. National Institute of Arthritis and Musculoskeletal and Skin Diseases.