OHSU study suggests hormone levels can be used to identify those at risk for injury
The study's results, published today in the American Medical Association journal Archives of Internal Medicine, strengthen the link between levels of the naturally produced male hormone and the health of men 65 and older. They also point to a new way of identifying men at risk for adverse events that put them at risk for injury and hospitalizations, and create a substantial health care burden.
In addition, the study provides more justification for trials of testosterone supplementation in older men and should aid in the design of those studies, according to the study's lead author, Eric Orwoll, M.D., professor of medicine (endocrinology, diabetes and clinical nutrition) and director of the Bone and Mineral Unit, OHSU School of Medicine.
"Like women on hormone replacement therapy, many older men are turning to testosterone therapy to regain some of what has been lost physically and mentally in the aging process," Orwoll said. "These results validate the need for more research on this trend in treatment for men in the advanced years of life."
For the study, researchers recruited 2,587 men ages 65 to 99 between March 2000 and April 2002 and collected samples of testosterone and estradiol, another sex hormone. The men also were tested for physical performance at the start of the study, since previous studies on the link between low testosterone and impaired physical performance have been inconclusive. Researchers then documented the participants' reported falls during clinic visits every four months for four years.
According to the study, 56 percent of the men reported at least one fall, and many fell frequently. Researchers found lower testosterone levels were associated with increased fall risk. In fact, men with the lowest testosterone levels had a 40 percent higher risk of falling than those with the highest testosterone levels.
The effect of low testosterone levels was most apparent in the youngest of the men studied, ages 65 to 69, whose fall risk was substantially higher than those in the higher age groups. Falls were not related to testosterone levels in men older than 80, who fell more often than younger men - 20 percent of men in that age group reported five or more falls, compared with 10 percent of the younger men - but whose risk for falls appeared more associated with low muscle mass and poor physical performance.
"In fact, low leg power or low grip strength was increasingly more predictive of fall risk as age advanced," the scientists wrote in the study.
However, previous studies have shown that older men with reduced testosterone levels treated with intramuscular testosterone experienced an increase in muscle mass and strength - two traits that have been found to help men avoid falls.
"... The positive effects of testosterone treatment on physical function justify interest in the possible benefits of therapy in older men," the researchers wrote.
Orwoll's collaborators on the study were at OHSU; the University of California, San Diego; the University of Pittsburgh; Minneapolis Veterans Affairs and the University of Minnesota; and the San Francisco Coordinating Center of the California Pacific Medical Center Research Institute of Medicine and the University of California, San Francisco.
The study was funded by the National Institutes of Health.