Men with low testosterone levels may be at higher risk of cardiovascular disease, according to a study review published in the Journal of Clinical Endocrinology and Metabolism.

Testosterone is a male sex hormone, important for maintaining sperm production, sex drive and bone health. Low testosterone levels have been found to cause increases in body fat, as well as loss of muscle bulk and body hair.

But now, researchers from Ghent University Hospital in Belgium have found that low testosterone levels may also be linked to a higher risk of developing or dying from cardiovascular disease.

To arrive at their findings, the research team examined previous studies that analyzed cardiovascular disease and testosterone levels between 1970 and 2013.

The review of the studies revealed modest evidence that low testosterone levels are linked to an increased risk of cardiovascular disease.

However, the researchers note there was little evidence of a link between low testosterone and artherosclerosis – the hardening and narrowing of the arteries that can lead to heart attacks and strokes, and there was no evidence of a specific link between heart attacks and testosterone levels.

Johannes Ruige, of Ghent University Hospital and lead study author, explains:

When we reviewed the existing research into testosterone and cardiovascular disease, a growing body of evidence suggested a modest connection between the two.

A specific pathogenesis did not come forward, but perhaps less frequently investigated events may play a role, such as thrombosis, where a blood clot develops in the circulatory system or arrhythmia, where there is a problem with the heart beat or rate.”

Additionally, the researchers found that although the number of older and middle-aged men are prescribed testosterone replacement therapy to treat low testosterone levels, the procedure appeared to have no positive effect on cardiovascular health.

Many of the reviewed studies did not provide information regarding causality of either condition, the researchers say, but the review did include 19 observational studies that provided information on whether one condition causes another.

Because this review has not ruled out potential causes of low testosterone levels and cardiovascular disease completely, the researchers say further research is needed to confirm the link between both conditions.

“Based on current findings, we cannot rule out that low testosterone and heart disease both result from poor overall health,” says Ruige.

“Gaps still remain in our understanding of low testosterone and cardiovascular disease. Ultimately, the goal is to more accurately assess the impact testosterone substitution therapy may have on the heart health of men who qualify for the treatment.”

Earlier this year, Medical News Today reported on a study that suggested Parkinson’s disease in men may be linked to a sudden decline in testosterone.