For some men, taking testosterone may triple the risk of having a heart attack, according to a new study.
Researchers looked at medical records of more than 48,500 men ages 65 and younger who were taking testosterone (in forms of gels, patches or injections), and followed them for three months.
The results showed that among men with a history of heart disease, 15 men per 1,000 had a heart attack during the three months after they started taking testosterone compared with five men per 1,000 before testosterone was prescribed.
For men who didn't have heart problems in the past, the risk of a heart attack didn't change when they started taking testosterone, according to the study published today (Jan. 29) in the journal PLOS ONE.
The findings add to the evidence of a link between testosterone and heart problems in men, the researchers said. [Macho Man: 10 Wild Facts About His Body]
"Patients and their physicians should discuss the risk of heart attacks when considering testosterone therapy," said study researcher, Sander Greenland, a professor of epidemiology at the University of California, Los Angeles.
Testosterone therapy is used in healthy older men to treat some symptoms of the diminished physical function that come with aging, such as loss of muscle mass and lowered bone density.
But middle-age men too have been increasingly taking testosterone therapy, a trend that some attribute to advertising campaigns about "low T syndrome." Over the past decade, prescriptions for testosterone for men ages 40 and older have more than tripled, according to a 2013 study in the journal JAMA Internal Medicine.
Concerns about negative effects of testosterone therapy on cardiovascular health were raised by several earlier studies, which mostly included men older than 60. Those studies found that taking testosterone may increase the risk for heart attacks and strokes.
In the new study, the researchers also looked at 7,000 men older than 65 who were taking testosterone therapy. In this older group of men, regardless of their history of heart disease, taking testosterone doubled the risk for heart attacks, confirming the previous findings.
Among the older men, those who didn't refill their prescriptions saw their risk of heart attack decline over the following months, compared with their risk level while taking testosterone, according to the study.