Is it True? Testosterone Causes Heart Attacks?

January was quite the tumultuous month for testosterone.

A study published in the Journal of the American Medical Association (JAMA) came to the conclusion that testosterone replacement in men in the Veterans Affairs (VA) system led to a high rate of heart attacks and stroke.  Another study published in the PLOS One journal came to a similar unsettling conclusion: Men who took testosterone had a greater risk of heart attack.

These findings  were surprising because these two studies – if taken at face value – reverse a mountain of scientific literature that documents testosterone’s significant safety profile in cardiovascular health.

So should men give up their testosterone prescriptions and the enhanced quality of life that they have come to enjoy?  The answer is no, and here’s why:

These two studies, if sound, would be very concerning.  But they both contain fatal procedural flaws in their study design that downgrades the weight of the evidence they bring.

But don’t take it from me.  Take it from Dr. Abraham Morgentaler of Harvard University, the nation’s top testosterone researcher.  Dr. Morgentaler has published over 50 articles in peer reviewed medical journals.  In a compelling article just published last week in the journal Nature Reviews Urology, Dr. Morgentaler reveals the startling truth about last month’s JAMA study.

The JAMA study’s authors concluded that the rate of cardiovascular events (heart attack or stroke) in the group of men who received testosterone was 25.7%, while only 19.9% of men in the non-testosterone group had such an event.

But the study’s own raw data did not support this conclusion.  To the contrary, the raw data showed that the men who took testosterone actually had fewer heart attacks and stroke.  Dr. Morgentaler explains:

“Among the 1,223 men who received testosterone therapy there were 67 deaths, 23 heart attacks, and 33 strokes, amounting to an overall event rate of 10.1% (123 events in 1,223 men).  By comparison, of the 7,486 men who did not receive testosterone therapy, there were 681 deaths, 420 heart attacks, and 486 strokes, meaning an overall major event rate of 21.2% (1,587 events in 7,486 men)—roughly twice the rate of events for men on testosterone therapy.”

In short: “…the twofold lower [heart attacks and stroke rate] in the testosterone group was reported to be greater after statistical manipulation.”

Putting it another way: Men who were not taking testosterone had about double the rate of heart attacks and stroke as men who took testosterone.

After Dr. Morgentaler and others pointed out this discrepancy, the study authors have since revised some of their wording to reflect the statistical somersaults they used to arrive at their conclusion.

I believe we can gain a bit of sanity from a study I blogged about in December, which noted the following common-sense thesis: Achieving mid-range blood levels of testosterone in older men taking testosterone replacement led to the best outcomes: The lowest heart disease risk and the lowest risk of dying from any cause compared to their peers.

As I mentioned back in December, moderation seems to be the key with testosterone replacement therapy.

References

Morgentaler A, Kacker R. Andrology: Testosterone and cardiovascular risk – deciphering the statistics. Nat Rev Urol. 2014. Feb 18.

Vigen, R., et al. Association of testosterone therapy with mortality, myocardial infarction, and stroke in men with low testosterone levels. JAMA 2013; 310(17):1829-36.

Finkle, W., et al. Increased risk of non-fatal myocardial infarction following testosterone therapy prescription in men. PLOS. January 29, 2014

Dr. Michael KaplanDr. Michael Kaplan is a naturopathic physician specializing in digestive health and men’s health.  He divides his time between his practice at the Tahoma Clinic North Seattle and Meridian Valley Lab, where he where he is sought after to assist other physicians with their most complex cases.