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14.03.2010

Effect of testosterone on heart research unreliable

It's an alarming piece of research, the meta-study that endocrinologists at the Mayo Clinic published in 2007. The researchers gathered together data from 30 trials in which a total of 808 men had been given testosterone. They analysed the data and cautiously concluded that testosterone is not drastically dangerous for the heart and circulatory system. But they don't regard the studies they used as completely reliable either.

The researchers used trials in which men had been given testosterone in the form of gels, injections, pills and patches. In the trials they used, men with a low testosterone level were mostly given gels and plasters, and occasionally an injection containing 200 mg testosterone ester. In the trials that used men with a low-normal or normal testosterone level, some were given Andriol capsules, others injections of up to 600 mg of testosterone ester per week. This last category most resembles chemical athletes who use testosterone. Trials on chronically ill men typically used doses of 100-250 mg of testosterone ester per week.

The figure below shows the overall effects of treatment in the three groups.

If we confine ourselves to the men with low-normal or normal testosterone levels, then it looks as though courses of testosterone are reasonably safe. Although the amount of triglycerides in the blood increases somewhat, other markers for cardiovascular disease go down. So, nothing to get worked up about, you might say.

The problem is though that markers are not the same as the disease itself. Whether your cholesterol count is a bit on the high side or a bit on the low side is not the same as whether you actually have a heart attack or not.

The researchers found 6 studies that recorded how many men during the testosterone administration did have a 'cardiovascular event': fatality, heart attack, burst aorta, that sort of thing. Six studies is not an unusually small number, and probably has something to do with the sponsors of most of the studies: the makers of testosterone preparations. Still. If you look at the cardiovascular events, then you realise that the chance of having a heart attack while taking testosterone doubles.

We're talking about small numbers, the researchers emphasise. The doubling of a small chance still only results in a small chance. But on the other hand the events are an indication, even if they are pretty rare. That most studies don't mention them says enough. And the researchers do decide that most of the testosterone trials are not completely reliable. "The best available evidence on this matter is inconsistent, imprecise, and poorly reported", they conclude. "As a result, clinicians and policymakers cannot be sure what consequences testosterone may have on cardiovascular risk."

And what goes for doctors also goes for chemical athletes. Steroids users' knowledge based on experience is that if you compare it with other steroids, high doses of testosterone are still safer than most.

Source:
Mayo Clin Proc. 2007 Jan; 82(1): 29-39.

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