In older men, low testosterone levels are associated with a variety of changes: decrease in sexual desire and erectile function, changes in mood and emotions, a decrease in strength due to loss of muscle tissue, an increase in body fat. And lowered bone mineral density. As lower testosterone is a common occurrence as men age , there has been an increase in sales and use of supplemental testosterone. However, remembering the late recognition of severe side effects with female hormone replacement therapy, there has been reluctance among most physicians to prescribe testosterone, especially when there isn't clear-cut evidence of a deficiency.

Now UK gerontologists writing in the journal Circulation have largely dispelled the anxiety about increasing testosterone levels artificially in men. They have shown in a large population-based study that as testosterone levels increase, the risk of death from cardiovascular disease and other causes, including cancer, decreases.

The analysis was done on 2,300 men between 40 and 79 at enrollment. They were followed for at least 10 years. The main comparison was of baseline testosterone levels between the 825 men who died and 1,489 men who didn't. After ranking the men according to testosterone levels, men in the highest 25% were 41% less likely to die during follow-up than those in the lowest 25% testosterone ranking. Each 6 nanomol/L of testosterone increase was associated with a 19% reduction in mortality risk.

A further boost for testosterone therapy ahs just appeared in the Journal of the American Medical Association.

There has been concern that high testosterone levels are a risk factor for prostate cancer. This doesn't seem to be the case, although there weren't enough prostate cancers in this study to be certain. However, there wasn't a general increase in cancer in those men with higher testosterone levels.

Maybe more men ought to be able to receive testosterone supplements now, based on these results? It looks like it would do more good than harm.