Coronary Heart Disease Linked to Endogenous Testosterone
SAN DIEGO—Higher levels of endogenous testosterone may associated with an increased risk of coronary heart disease (CHD) in men older than 65 years, according to a large U.S. multi-center study presented at the Endocrine Society's 92nd annual meeting.
“The study finding contradicts smaller studies that have shown that testosterone levels are not associated with higher rates of cardiovascular disease,” said study investigator Kristen Sueoka, MD, a resident physician in the Department of Internal Medicine at the University of California, San Francisco. “Many in the general public are using testosterone supplements for various medical problems, including low sex drive and mood disorders, which are not life-threatening. These men may unknowingly be placing themselves at higher risk for cardiovascular disease.”
Dr. Sueoka and her colleagues examined endogenous sex hormone levels in older men as an independent risk factor for CHD events. They studied 697 community-dwelling men who were participating in the National Institutes of Health-funded study, Osteoporotic Fractures in Men (MrOS). None of these men were receiving testosterone therapy and all the men were recruited between 2000 and 2002 at six U.S. centers. The men had a mean age of 72 years. Investigators collected and stored fasting serum samples from the subjects at enrollment.
During an average follow-up of 3.9 years, 100 men (14%) had a coronary disease event. Men with total testosterone levels in the highest quartile (495 ng/dL or higher) had a 2.2 times increased risk of a CHD event compared with men in the lowest quartile (below 308 ng/dL). The researchers also found that the results were similar for bioavailable testosterone and free testosterone. Higher sex-hormone-binding globulin levels also were associated with an increased risk for CHD events, but estradiol and estrone levels were not.
“Our findings suggest there is some type of pathogenesis or interaction that is going on,” Dr. Sueoka said. “If a causal relationship is found between high testosterone and cardiovascular disease, then that would suggest that replacement therapy may put people at higher risk for cardiovascular disease.”
The investigators did not divide the men by normal or abnormal testosterone levels because the definition of abnormal levels depends on many factors, including increasing age. “Men with the highest testosterone could potentially be at risk for heart disease regardless of the definition of ‘normal' levels,” Dr. Sueoka said.