Low Testosterone, Increased Fracture Rate

Everyone knows that the decrease in estrogen levels women experience after menopause is associated with osteoporosis - and the increased risk of bone fractures. So one of the treatments for osteoporosis used to be hormone replacement, until the scare about estrogen side-effects took force. But there are age-related declines in sex hormone levels in men, too; one of them is, not surprisingly, testosterone.

Researchers at Basel University, Switzerland, examined 600 men of average age 73, looking at hormone levels, calcium intake, smoking habits, and spine bone mineral density (BMD). During the 6-year follow-up, fractures were counted.

During follow-up, 19% of the men had a low-trauma fracture. These men were slightly older, and had lower weight, height, BMD, calcium intake, and serum levels of testosterone than those without fractures. Analyses showed that lower testosterone levels at baseline were significant ‘predictors’ of a low-trauma fracture in the next 6 years.

This is a serious finding. Hip fractures are particularly catastrophic in older men; they are more likely to die or be chronically disabled afterwards than women. What’s problematic is that low testosterone levels are not associated with reduced BMD, as low estrogen is in women. The scientists theorize that lower testosterone may be related to reduced muscle strength and unsteadiness, increasing the risk of falls and fractures. And there’s always the possibility that estradiol is the important hormone to measure (as in women), because testosterone is converted to estradiol in the body. One thing, it’s clear that we know far less about older men’s risk of fractures that we do of women’s. More research is needed!