Perhaps you have heard the TV ads for lawyers interested in filing suits for testosterone injuries. This advertising springs from the recent article entitled “Association of Testosterone Therapy With Mortality, Myocardial Infarction, and Stroke in Men With Low Testosterone Levels” by Vigen et al. This research paper concludes the onset of testosterone therapy in certain men can cause an increase in heart attacks and strokes

There has been 40 years of research on testosterone with an opposite conclusion. Declining testosterone levels are associated with an increase in heart failure, an increase in heart attacks, increased mortality from heart attacks and strokes, and an increase in all causes of death . Testosterone also can decrease plaque in the arteries (even statins can’t do this), and lower cholesterol levels.

Why does this study have such different results from the 40 years of research? This study is observational, and retrospective. Researchers collated the data after-the-fact. The intervention (testosterone therapy) was uncontrolled. For example, we don’t know what type of testosterone these men took. We don’t know if they achieved therapeutic testosterone blood levels. We don’t know if they took the hormone at all. Did these men start smoking during this interval? We don’t know about these and many other variables. It is hard to determine causation in a study like this.

Most of the serious studies on testosterone are meta-analysis, double blind controlled studies. These large studies have conditions which are controlled at the onset, and the subjects are randomly given the intervention. Then the data is collected.

But we must take this information, and put it in a larger perspective. There are 40 years of research, and this one interesting study. Perhaps testosterone is not of benefit to men with advanced cardiac disease or to elderly men. There are more questions to be answered. This one retrospective, observational study deserves careful thought, but not radical therapy change.