Although men suffer more coronary heart disease than women, the blame should not be placed on testosterone, according to a new study in the May 17, 2005, issue of the Journal of the American College of Cardiology.
“Our findings confirm that in healthy middle-aged men normal testosterone levels are protective against atherosclerosis. Previous studies in elderly men, obese men and in men with diabetes have similarly suggested that testosterone levels are inversely associated with atherosclerosis,” said Olli T. Raitakari, M.D., Ph.D., at the University of Turku in Turku, Finland.
The researchers, including lead author Juuso Mäkinen, M.D., studied 99 generally healthy middle-aged men who had symptoms of “andropause,” including fatigue, low libido or depression and, also, either low levels of testosterone or high levels of luteinizing hormone along with normal testosterone levels. Ultrasound measurements of the thickness of the inner layer of their carotid arteries, which is an indication of the extent of atherosclerosis, were compared to the results from 140 men who did not show signs of andropause.
The maximum thickness from the lumen intima interface of the carotid artery to the next layer, the media adventitia interface, was higher in the andropausal men. Also, this intima-media thickness was inversely correlated with testosterone levels; that is, the less testosterone, the thicker the intima-media complex, indicating more advanced atherosclerosis.
Dr. Raitakari said that the results indicate that the commonly-held view, that estrogen is good for heart health and testosterone is bad, is too simplistic. In addition, he noted that experimental laboratory and animal studies have tended to point toward harmful effects of testosterone, while on the contrary, this study and others in humans show potential benefits.
“The evidence overall is starting to show that normal testosterone levels in aging men are good for the heart,” Dr. Raitakari said. “The results also remind us that experimental and clinical studies can give totally opposite results. Therefore, all effects shown in experimental in vitro and animal studies should be verified also in humans.”
This study also found that intima-media thickness rose with higher levels luteinizing hormone. The researchers said this is the first study to indicate that luteinizing hormone may be linked to atherosclerosis.
Dr. Raitakari pointed out that this study included a relatively small number of participants who were all Caucasian and middle-aged, so researchers cannot say for sure that the same results would be seen in other populations. Also, the study just took a snapshot of hormone levels and carotid artery wall thickness. It did not follow the men over time to see who actually developed symptoms of atherosclerosis or other cardiovascular disease.
This study adds urgency to questions about whether men with low testosterone should be treated, Dr. Raitakari said.
“These data indicate that controlled studies are needed to study the effects of testosterone supplementation. More data on safety are needed; especially the potential risk of prostate cancer or hypertrophy should be evaluated before supplementation could be recommended,” he said.
Elizabeth Barrett-Connor, M.D., at the University of California-San Diego campus in La Jolla, who wrote an editorial appearing in the journal, noted that this study and others are challenging the belief that the female advantage in terms of coronary heart disease is due to either protective effects of estrogen or harmful effects of testosterone.
“This study suggests that higher testosterone levels are associated with less atherosclerosis in the carotid arteries, and that’s contrary to what we thought. And on the other hand, most middle-aged men who complain of low libido, fatigue or the other complaints that go with “andropause” symptoms, don’t actually have low testosterone levels. These results suggest that testosterone is not as bad for your heart as we had thought. Clinical trials of testosterone therapy will be necessary to confirm this idea,” Dr. Barrett-Connor said.
Dr. Barrett-Connor also pointed out that only 6 percent of middle-aged men evaluated by these researchers had both symptoms of andropause and low levels of testosterone.
The American College of Cardiology, a 31,000-member nonprofit professional medical society and teaching institution, is dedicated to fostering optimal cardiovascular care and disease prevention through professional education, promotion of research, leadership in the development of standards and guidelines, and the formulation of health care policy.