New findings strengthen link between testosterone levels and health of older men

Low testosterone levels may be associated with a higher risk of falling in older men, according to a report in the October 23 issue of Archives of Internal Medicine.

The level of testosterone in a man's blood--including the amount that is bioavailable, or able to be used by the body--declines as he ages, according to background information in the article. Some researchers have speculated that this decline in sex hormone levels contributes to health conditions associated with aging; however, few studies support this notion. Muscle weakness and muscle loss are two adverse events that often occur with age and are known to increase the risk of falling among older adults.

Eric Orwoll, M.D., Oregon Health & Science University, Portland, and colleagues studied 2,587 men age 65 to 99 (average age 73) who enrolled in the Osteoporotic Fractures in Men (MrOS) Study between 2000 and 2002. At the beginning of the study, blood samples were taken and participants filled out questionnaires about their medical history, medications and lifestyle habits. The men completed several physical performance tests, including those assessing grip strength, leg power and balance. Every four months, they reported whether they had fallen and if so, how many times.

During the course of the study, which continued until March 2005, 56 percent of the men fell at least once. Those with lower bioavailable testosterone levels were significantly more likely to fall and to fall multiple times than those with higher levels--among the one-fourth of participants with the lowest testosterone levels, the risk for falling was 40 percent higher than among the one-fourth with the highest testosterone levels. The association was stronger in younger men (ages 65 to 69) and not apparent in men older than 80.

The association remained the same when the researchers factored in the scores on physical performance tests.

"Bioavailable testosterone concentration is associated with measures of physical performance, but the association of testosterone level to the risk of falling is apparent regardless of physical performance," the authors write. "Thus, the mechanisms by which testosterone level affects the propensity to fall may involve other pathways." For example, low testosterone levels could impair vision, thinking processes or coordination, increasing the risk for falls.

"These findings strengthen the link between testosterone and the health of older men, suggesting that the effects of testosterone on fall risk may be via novel mechanisms and provide insight into how testosterone measurements might be useful for identifying men at higher risk for adverse events," the authors conclude. "Moreover, these results provide additional justification for trials of testosterone supplementation in older men and should aid in the design of those studies."