Researchers Study Role of Low Testosterone on Older Men

Researchers in Australia have released the results of a study showing that dropping testosterone levels in older men could potentially put them at risk when taking care of themselves in their later years.

Data was collected from more than 1,300 men ages 70 and older and compared their initial hormone levels with their abilities two years later. Their findings were presented at the joint meeting of the International Society of Endocrinology and the Endocrine Society in Chicago.

Men who participated in the study underwent objective tests of strength in their arms, legs and hands. They also provided reports on their ability to do normal self-care activities such as walking, eating, dressing and bathing.

Researchers took that data and adjusted for known risk factors associated with physical decline such as older age, smoking and obesity when looking at their final results.

When reporting their findings the team said that lower levels of testosterone, estradiol or estrone at the outset correlated with greater risk of decline. Results showed that men who started with the lowest levels of these hormones were twice as likely to suffer notable declines as those who began with the highest levels.

“We also found that increasing muscle weakness — possibly due to decreasing testosterone concentration in the blood — could explain most of this relationship,” said Benjumin Hsu, the study's principal investigator and a PhD candidate at the University of Sydney.

Initial testosterone levels taken during the study period predicted both declines in strength and declines in function, but, after researchers adjusted final declines in function for declines in strength, low initial testosterone levels did not predict a further loss of function.

The study team also noted that while testosterone levels and the ability to perform self-care activities both tend to decline with age, it is unclear whether either factor causes the other or whether a third unexplored factor causes both.

“Low testosterone, estradiol and estrone concentrations may be important contributors to, or biologic markers for, physical decline in older men, which impairs their independent living,” Hsu said.

The study was part of the Concord Health and Ageing Project (CHAMP) in Sydney, which included 1,318 men ages 70 and older who had health assessments when they entered the study from 2005 to 2007, and again two years later.

The CHAMP study has been funded by three Australian institutions: the National Health and Medical Research Council, the Sydney Medical School Foundation and the Ageing and Alzheimer’s Institute.