Testosterone and Its Impact On the Heart-Here’s the Good News

I am frequently queried by my patients about the safety of using testosterone and the risk of developing heart disease or a stroke. I would like to give you the evidence from the medical literature, and then help you make an informed decision if testosterone replacement is right for you.

Men have more than twice the risk of dying from coronary disease than women. It has been assumed that testosterone is deleterious to the male cardiovascular system and contributes to the risk of heart disease. In fact, there is little evidence that testosterone produced in body by the testicles is an adverse risk factor but the role of testosterone status and replacement therapy on male health is controversial.

High doses of anabolic steroids often used by body builders and athletes are undoubtedly associated with cardiac disease but these are doses much higher than what the body normally produces. Testosterone levels within the normal range do not appear to be harmful. Indeed, low rather than high testosterone levels in men are associated with several cardiovascular risk factors including an atherosclerosis or hardening of the arteries, insulin resistance, and obesity.

Let me give you information first from animal studies where the scientists can control the variables. Studies in male animals have shown that castration or induced hypogonadism increases atherosclerosis and testosterone replacement prevents this. In addition, testosterone has beneficial effects in men with cardiac disease. Testosterone is a potent coronary artery vasodilator. Testosterone therapy reduces total cholesterol, fat mass, waist circumference and pro-inflammatory cytokines associated with atherosclerosis, diabetes and the metabolic syndrome. Testosterone also improves functional capacity of the heart and insulin resistance in men with heart failure.

In an ageing male population low serumotal testosterone is common and has a prevalence of 30% in men over the age of 60 years. Testosterone deficiency may cause undesirable effects such as loss of bone and lean body mass, increased adiposity, low energy and impaired physical and sexual function. Until recently, these effects were viewed as the natural physiology of aging; however, four recent major studies have found low testosterone to be associated with increased all-cause mortality after controlling for baseline morbidity and age.

The effect of testosterone on mortality has demonstrated an increased risk of death due to cardiovascular diseases in men with low testosterone. One report found that mortality due to any cause and cardiovascular mortality was increased with a reduction in serum testosterone. Low testosterone status is therefore associated with mortality and vascular mortality, yet no study has specifically examined patients with established cardiovascular disease. This is important because men with manifest coronary artery disease are at a higher risk of cardiovascular mortality and represent a patient population prone to testosterone deficiency. In addition, those men with angina, chronic heart failure or diabetes may derive particular symptomatic benefit from androgen replacement therapy.

This study had two aims: first to assess the impact of testosterone status on life expectancy in men with pre-existing coronary disease, and second to identify the prevalence of biochemical testosterone deficiency in men with coronary disease. Our hypothesis was that low serum testosterone would be associated with an adverse survival.

One excellent study that was peer reviewed showed that the prevalence of testosterone deficiency is common in men with coronary disease and is present in 25% of the men. The data have confirmed that low T is related to all-cause and vascular mortality in a coronary disease population. Therefore, the study also concluded that borderline low levels of T may also have an adverse impact on survival.

This study is entirely consistent with previous studies of low testosterone as a cause of decreased life expectancy.

What is the pathophysiology of low testosterone status and the apparent increased mortality of atherosclerotic disease? Animal data show that testosterone deficiency accelerates atheroma or atherosclerosis and replacement with testosterone prevents this. Human studies have shown an increased progression of atheroma in men with lower testosterone. These data therefore suggest that testosterone deficiency is associated with progressive atherosclerosis and replacement, in animals at least, prevents this progression of the heart disease.

We have demonstrated that testosterone deficiency is associated with premature death in male patients with vascular disease; many of these patients died and will continue to die from cardiovascular disease. There is scientific evidence and several documented trials showing benefit in terms of risk factor modification and symptoms. If androgen deficiency is part of the underlying pathophysiology of atherosclerotic disease in men, then the serum testosterone level could be viewed as a modifiable risk factor as men can increase the T level by testosterone replacement therapy. Physiological testosterone replacement is an inexpensive and well-tolerated therapy but does require careful monitoring.

Bottom Line: Testosterone deficiency is common in middle aged and older men. Low testosterone levels appear to cause men to be at an increased risk of cardiovascular disease and even increased risk of death. Hormone replacement therapy for men who are symptomatic may be protective of heart disease but these men require close follow up consisting of a PSA test, a digital rectal exam, and a blood count to check that there is not an increased production of red blood cells.

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