Coronary artery disease is one of the most dangerous chronic diseases in America today. Coronary artery disease, or CAD, occurs when the tiny coronary arteries that supply the heart with oxygenated blood gradually become narrowed or blocked with plaque. These plaques are made from cholesterol and other materials. Early symptoms of coronary artery disease include chest pain (e.g., angina), shortness of breath, and fatigue. As the disease progresses, symptoms can become more severe. If a plaque ruptures and sends bits of material cascading down the artery, a blockage can occur. This is known as a heart attack.The most common causes of CAD are hereditary, lifecycle factors like diet, and obesity. However, many people don’t realize that testosterone status is also closely associated with CAD. As men age and their testosterone levels decrease, it comes as no surprise to hormone researchers that the rate of CAD goes up. In fact, CAD is closely associated with low levels of testosterone.
In recent years, researchers have discovered that low testosterone levels promote the accumulation of fatty cholesterol-laden plaques on the inner walls of the arteries, a condition known as atherosclerosis. In contrast, higher levels of testosterone are associated with less extensive CAD. One research group showed that testosterone replacement therapy in mice fed a cholesterol-enriched diet for 28 weeks reduced fatty streak formation—this is the first visible step in the development of atherosclerosis. This study also showed that testosterone replacement therapy was associated with higher levels of the protective HDL cholesterol. HDL helps remove excess “bad” cholesterol from the blood and is associated with a reduced risk of atherosclerosis and other cardiovascular diseases.
Human studies on testosterone and CAD have also been encouraging. Webb et al investigated the effect of testosterone therapy on the coronary artery among 13 men with CAD and found that short-term intracoronary administration of testosterone increases blood flow to the heart.
The Relationship of Low Testosterone and Coronary Artery Disease
Low testosterone is often found in men with heart failure, and the severity of the disease is typically proportional to the level of reduction in testosterone. Some researchers have also speculated that men are at a higher risk of CAD overall because of the dramatic drop in their testosterone levels as they age.
To demonstrate the relationship of low testosterone and CAD, English et al measured the testosterone levels of 90 men with CAD and discovered that they have significantly lower levels of the hormone. Another long-term survey found that a decrease in testosterone was associated with a 25% increased risk of dying. Finally, Barrett-connor et al investigated the testosterone levels of 1,009 white men aged 40-79 years with a 12-year follow-up period and found an association between low levels of testosterone and increased risk of dying from CAD-related causes regardless of age, body mass index (BMI), smoking status, waist-to-hip ratio, and lifestyle.
Based on these results, men who are currently under treatment for coronary artery disease or heart disease are encouraged to get their testosterone levels measured. If their testosterone levels are low, testosterone replacement therapy might be recommended.