Testosterone vs Heart Disease Part 2

When it comes to interpreting medical information, sometimes it feels as if the data is represented by a tennis ball batted back & forth during a match.  Much of what medical news makes the headlines in the media is due to just that - the need to make headlines.  It's much easier to jump to eye-catching conclusions in a short headline phrase rather than explain in detail the difference between randomized controlled trials vs observational data as our eyes tend to glaze over w/dullness as we discuss the limitations of observational data to developing hypotheses.  More egregious are those writers who would put cellular & basic life-form data on the front page, extrapolating & making claims as to the next cure for cancer & dementia.

Because much of what we need to know is not amenable to large scale, long term, randomized, double-blind, placebo-controlled trials, we are therefore left to make do w/observational, epidemiological data.  In these situations, when we cannot prove cause & effect, it's always helpful to search for outcome trends, rather than flukes.  Therefore, in support of an association between testosterone and heart disease, I would like to point out yet another study to be published next week in the Journal of the American College of Cardiology concluding that higher testosterone is linked to lower risk of heart disease in men.

Specifically, this is a re-analysis of data from the Osteoporotic Fractures in Men (MrOS) study in which 2,416 overweight (average body mass index (BMI) 26.4 kg/m2) elderly (average 75yo) Swedish men were followed for 5 years.  At baseline, those in the lowest quartile of testosterone had an average of 255ng/dL which you will recall is just at the lower limits of normal for most laboratories.  Those in the 2nd quartile had an average of 389ng/dL while those in the 3rd quartile had an average of 491ng/dL.  Men in the highest quartile of testosterone had an average of 680ng/dL.  Free testosterone correlated w/total testosterone.  Coincidentally (or not), BMI was inversely associated to testosterone level.

In comparing those men in the highest quartile of testosterone (>550ng/dL) to the lowest (<340ng/dL), the authors noted a 29% lower risk of cardiovascular events.  And in comparing those in the highest quartile to those in the lowest 3, the authors noted a 30% lower risk of cardiovascular events.  But lest you take this latest study to your family physician and ask for a prescription of testosterone, be warned that this study should only be applied to older Swedish men until the findings can be duplicated in other populations.  

Also note that these testosterone levels were endogenous in nature.  In other words, these levels were naturally present, not as a result of supplementation.  Therefore, one might also hypothesize that testosterone is necessary for a longer period of time for it to be effective.  Regardless, one cannot and should not use this study to support testosterone supplementation for the sake of cardiac benefits.  On the other hand, this is clearly another study that supports a trend towards cardiac benefit from higher testosterone levels.

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