We associate testosterone with big muscles. Of course, they increase the muscle mass, but do not forget they are also responsible for the bigger bones of the males. And as men experience andropause, this affects not only muscles and sex drive, but bones as well.

A new research published in the Archives of Internal Medicine has found that decreased testosterone levels in men over age 60 translates into a higher vulnerability to fractures. 33% of all osteoporotic fractures were known to be experienced by men, and those with a previous osteoporotic fracture are 3 to 4 times more vulnerable to another fracture than a woman of similar age with a fracture.

"Understanding the determinants of fracture risk in men may reduce the burden of disease through facilitating better prevention strategies," the authors wrote .

The team at the University of Sydney, Concord, New South Wales, Australia, followed up 609 men (average age 72.6) between January 1989 and December 2005, assessing their bone mineral density, lifestyles, blood testosterone and estrogen levels at the beginning of the research. The follow up recorded the occurrence of low-trauma fracture (caused by a fall from standing height or less) and testosterone levels at those moments. 113 subjects experienced low-trauma fractures, significantly increased in the case of those with low testosterone amounts.

"25 men experienced multiple incident fractures. A total of 149 incident fractures were reported, including 55 vertebral, 27 hip, 28 rib, six wrist and 16 upper and 17 lower extremity fractures. After adjustment for sex hormone−binding globulin (a blood protein), serum testosterone and serum estradiol levels were associated with overall fracture risk. After further adjustment for major risk factors of fractures (age, weight or bone mineral density, fracture history, smoking status, calcium intake and sex hormone−binding globulin), lower testosterone was still associated with increased risk of fracture, particularly with hip and non-vertebral fractures," the authors added.

"Although low levels of estradiol and testosterone were associated with a higher risk of fracture in men over 60, only the effect of testosterone was independent of other risk factors. While testosterone may affect fracture risk via skeletal and non-skeletal mechanisms, the present findings suggest that measurement of serum testosterone provides additional clinical information for the assessment of fracture risk in elderly men," they concluded.