Testosterone Does Not Cause Atherosclerosis (Hardening of the Arteries) in Older Men

Unless you have been imitating Rip Van Winkle for several years, you are aware that Testosterone Replacement Therapy (TRT) has exploded in the last decade.

However, there have been very few studies that have examined the long-term effects of taking testosterone on cardiovascular health and other vital functions concerning the health effects on men receiving the treatment.

But that has changed.

Recently, investigators from Brigham and Women's Hospital (BWH) report the results of Testosterone's Effects on Atherosclerosis Progression in Aging Men (TEAAM) trial in the Journal of the American Medical Association (JAMA).

The three-year study finds that testosterone administration had no effect on the progression of hardening of the arteries in older men with low to low-normal testosterone levels and did not significantly improve sexual function or health-related quality of life.

Shehzad Basaria, M.B.B.S., MD, from Harvard Medical School in Boston, and colleagues studied the effect of testosterone administration on atherosclerosis progression in older men.

Three hundred eight men aged 60 years or older (patients had a mean age of 67.6 years), with low or low-normal testosterone levels, volunteered and were treated with up to 7.5 g of 1 percent testosterone (156 men) or placebo gel packets (152 men) daily for three years.

In testosterone-treated patients, doses were adjusted periodically to achieve testosterone levels between 500 and 900 ng/dL.

Additionally, 42% of participants had hypertension, 15% had diabetes, 15% had cardiovascular disease, and 27% were obese.

The researchers assessed sexual function using the International Index of Erectile Function, a validated 15-item questionnaire that assesses five domains of sexual function (erectile function, orgasmic function, sexual desire, intercourse satisfaction, and overall sexual satisfaction).

They used the Medical Outcomes Study 36-item short-form health survey (SF-36) to assess health-related QOL.

"The results of this trial suggest that testosterone should not be used indiscriminately by men," said Dr. Bhasin, director of BWH's Research Program in Men's Health: Aging and Metabolism and director of the Boston Claude D. Pepper Older Americans Independence Center at BWH.

He added that "We find that men with low and low-normal testosterone are unlikely to derive benefits regarding sexual function or quality of life -- two reasons why men may seek testosterone therapy.

And although we find that testosterone did not affect the rate of hardening of the arteries, we need long-term data from large trials to determine testosterone's effects on other major cardiovascular events."

No Significant Difference

The researchers also observed no significant difference in the rate of change in intima-media thickness (a measurement of the thickness of the innermost two layers of the wall of an artery...0.010 mm/year in the placebo group versus 0.012 mm/year in the testosterone group; P = 0.89) or in the rate of change in the coronary artery calcium score, which is a cardiac CT scan for coronary calcium in a non-invasive way of measuring calcified plaque in the coronary arteries — the vessels that supply oxygen-containing blood to the heart muscle...(41.4 versus 31.4 Agatston units/year; P = 0.54).

In the individuals assigned to receive testosterone, changes in intima-media thickness or calcium scores had no link with a difference in testosterone levels.

There was no significant difference between-group sexual drive, erectile dysfunction, sexual function ability, partner intimacy, or health-related quality of life.

"Our research shows convincingly that testosterone therapy does not affect the rate of atherosclerosis progression, but we need much larger, randomized trials to determine if testosterone treatment impacts heart attack and stroke risk," Bhasin told MedPage Today.

He added that if this is the case, the mechanism does not appear to be through the treatment's impact on atherogenesis.

"Testosterone may be affecting some other mechanism, such as plaque stability or clotting within the blood vessel," he said.

"Because this trial was only powered to evaluate atherosclerosis progression, these findings should not be interpreted as establishing the cardiovascular safety of testosterone use in older men," the authors write.

"Our study has important implications for clinical practice, and for older men who are seeking testosterone therapy," said Bhasin.

"Many men, as they age, experience a decline in testosterone and sexual function and vitality.

But our study finds that taking testosterone, when levels are in the low to the low-normal range, may not improve sexual function or quality of life."

The study was supported by Solvay Pharmaceuticals/Abbvie Pharmaceuticals, which provided testosterone and placebo gel.

Testosterone, a hormone primarily secreted by the testicles, plays a vital role not only in male reproductive tissues but also in muscle growth, bone mass, and body hair.

As men get older, their testosterone levels naturally decline -- on average by 1 percent a year after age 40.

Previous studies that have aimed to examine rates of cardiovascular events in men taking testosterone have reported conflicting results but have raised concerns that testosterone therapy might increase a person's risk of a heart attack or stroke.

Atherosclerosis, or the buildup of plaque in the arteries, is a critical risk factor for such cardiovascular events.

But Cardiovascular Safety for TRT Remains an Open Question

While earlier studies examining the impact of TRT on cardiovascular disease (CVD) risk in older men have been mixed, the TEAAM trial was not powered to weigh in on testosterone's effect on CVD events in this population, the researchers warned.

As a result, the findings should not be interpreted as establishing the treatment's safety in older men, they emphasized.

The TEAAM trial was designed to examine atherosclerosis progression and not cardiovascular events — further studies will be needed to determine the cardiovascular safety of testosterone use in older men.

The research team also notes that comparing patients using statins to those who are not could be another important direction for future studies.

Baseline characteristics among the treatment and placebo groups were similar: mean patient age at randomization was 67.6 years, 42% of participants had hypertension, 15% had diabetes, 15% had cardiovascular disease, and 27% were obese.

The authors reported that the rate of change in the CAC score was 41.4 Agatston units/year in the placebo group and 31.4 Agatston units/year in the testosterone group for an adjusted mean difference of 10.8 Agatston units/year (95% CI 45.7 to 24.2, P=0.54).

Study limitations included the high rate of loss to follow-up and the fact that the effectiveness of participant blinding was not assessed.

Bhasin said the failure to show a positive impact on these secondary endpoints has significant implications for the use of TRT in relatively healthy middle-aged and older men.

He said the dramatic rise in TRT use among relatively healthy, aging men with borderline low testosterone levels over the last decade had been primarily driven by the desire to improve sexual function and QOL.

"Testosterone is being used indiscriminately, and it shouldn't be," he said.

"Many middle-aged and older men are seeking this treatment to address sexual symptoms or to improve their quality of life. Our study clearly showed that the treatment has little impact in men whose testosterone levels are near normal."

He noted that although several large, randomized trials evaluating TRT in older men are nearing completion, including the NIH's Trial, they are not designed to determine CVD risk.

"We need a TRT test with cardiovascular event rate as the primary outcome, and it needs to happen fairly quickly," he said.

Reference

Testosterone Treatment and Coronary Artery Plaque Volume in Older Men With Low Testosterone.

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