Cardiovascular Disease and Testosterone
Heart attack and stroke are the leading cause of death in the United States today. Heart disease is responsible for over 40% of all the deaths in the United States, more than all forms of cancer combined. Many forms of heart disease can be prevented or treated with healthy lifestyle choices and diet and exercise. Cardiovascular disease is caused by narrowed, blocked or stiffened blood vessels that make the delivery of blood and oxygen to your heart, brain and other parts of the body greatly diminished. Symptoms of cardiovascular disease include: chest pain, called angina, shortness of breath, and pain, numbness and coldness in the arms and legs. Most of the time, cardiovascular disease is not diagnosed until the condition has worsened to the point that someone has a heart attack, chest pain, stroke, congestive heart failure or sudden cardiac death. Therefore it is of the utmost importance to begin screening for cardiovascular disease earlier rather than later and discuss any questions about and any symptoms that you are experiencing with a doctor.
While cardiovascular disease can refer to many different types of heart or blood vessel problems, the term is often used to mean damage caused to the heart or blood vessels by atherosclerosis, a buildup of fatty plaques in arteries. Arteries are blood vessels that carry oxygen and nutrients from the heart to the rest of the body. Healthy arteries are flexible and strong. Over time, however, too much pressure in arteries can make the walls thick and stiff — sometimes restricting blood flow to vital organs and tissues. This process is called arteriosclerosis, or hardening of the arteries. Atherosclerosis is the most common form of this disorder. Atherosclerosis is also the most common cause of cardiovascular disease, and it’s caused by an unhealthy diet, lack of exercise, being overweight and smoking. All of these are major risk factors for developing atherosclerosis and, in turn, cardiovascular disease.
Another factor that plays a substantial role in the development of cardiovascular disease is declining testosterone levels seen in andropausal men. Men are more than twice as likely as women to develop cardiovascular disease. Pre-menopausal women have a lower risk of developing cardiovascular disease but this incidence rises after menopause. Thus, estrogen seems to play a protective role in the development of cardiovascular disease in women. Little attention has been paid to the role that testosterone plays in the pathogenesis of cardiovascular disease. As testosterone declines with advancing age, the prevalence of cardiovascular disease has been shown to increase. The more elderly population which has the highest cardiovascular disease prevalence has relatively low testosterone levels. Furthermore, males with cardiovascular disease have lower testosterone then men without.
Different patterns of cholesterol lipid levels and apoproteins, small molecules that carry cholesterol in the body, also play a role in the pathogenesis of cardiovascular disease. High total cholesterol, high LDL lipid levels, high triglycerides, and elevated lipoprotein-a have all been shown to be highly causative of cardiovascular disease, while high HDL has been shown to be protective. The majority of studies have shown that with higher testosterone levels the higher the HDL levels are and the lower the LDL, triglyceride and total cholesterol levels thus relating to a lower risk of developing cardiovascular disease.
Obesity and Testosterone
Weight gain seems to be an inevitable part of the aging process. This seems to be very highly related to the fact that men’s testosterone levels decline with age. The increase in weight is related to the frequent concomitant development of insulin resistance and diabetes that are often seen in andropausal men. High levels of insulin and cortisol, both needed for proper blood sugar regulation, along with decreased free testosterone levels in the aging male can lead to lipid accumulation. The lipid accumulation results in more deposition of visceral fat, especially in the abdominal region, rather than subcutaneous fat. This leads to the typical increase in waist-to-hip ratio (WHR) seen in aging men. Visceral fat has a high density of androgen receptors and when testosterone is in adequate quantities it helps to inhibit the accumulation of fat. However, with the natural diminution of testosterone in andropause this inhibition is slowed down and more visceral fat tends to accumulate. The situation is confounded by the fact that adipose tissue aromatizes testosterone into estrogen, further depleting testosterone in the aging male.
It has been shown that men who are deficient in testosterone given hormone replacement have reductions in visceral obesity and an improvement in their WHR. With testosterone replacement there also seems to be a reduction in other aspects of metabolic syndrome, including insulin resistance and diabetes and an increase in lean muscle mass.
Insulin Resistance, Diabetes and Testosterone
Insulin is a hormone that is responsible for the uptake of glucose into cells from the bloodstream after a meal. When people are insulin resistant, their muscle, fat, and liver cells do not respond properly to insulin. As a result, their bodies need more insulin to help glucose enter cells. The pancreas tries to keep up with this increased demand for insulin by producing more. Eventually, the pancreas fails to keep up with the body’s need for insulin. Excess glucose builds up in the bloodstream, setting the stage for diabetes. Many people with insulin resistance have high levels of both glucose and insulin circulating in their blood at the same time. Insulin resistance increases the risk for developing Type II Diabetes Mellitus and cardiovascular disease.
Although not the primary risk factor, decreasing bioavailable testosterone levels in men seem to play a substantial role in the pathogenesis of insulin resistance and diabetes. Numerous studies have consistently found a negative correlation between bioavailable testosterone and fasting glucose or fasting insulin – the lower the amount of testosterone found in men, the higher the fasting glucose and insulin. Both high insulin levels and low testosterone separately predict the onset of type 2 diabetes. People with diabetes appear to have lower testosterone levels than normal males. A study of 110 men with type 2 diabetes found that the lower the level of testosterone in men, the worse that they were able to control their blood sugars. Intervention studies with testosterone treatment within the physiological range document improved insulin sensitivity in elderly and obese men.
Benign Prostatic Hyperplasia (BPH)
Benign Prostatic Hyperplasia (BPH) is a condition of excessive proliferation of prostate cells and an enlarged prostate gland that probably occurs as part of the normal aging process in men. The prostate gland sits beneath the bladder and surrounds the urethra — the tube that drains urine from the bladder. When it becomes enlarged, the prostate can put pressure on the urethra and cause difficulty urinating.
With aging it is almost universal in men to have an enlarged prostate gland. It is most commonly seen in men over the age of 40, and 50% of men over the age of 50 have enlarged prostates. Although an enlarged prostate, or benign prostatic hypertrophy (BPH), may not cause men any difficulties in everyday functioning, often it can lead to problems with urination such as decrease in force of urination, sensation of incomplete voiding, increased frequency in urination, and dribbling of urine.
As men age, testosterone in the body is converted more into dihydrotestosterone (DHT) in the prostate which has a direct relation to increasing prostate size. Sex hormone binding globulin (SHBG) also plays a role in the development of BPH and of many changes that occur in andropause. There is an SHBG receptor on prostate gland cells which allows steroid hormones, like testosterone and estrogen, to bind and exert their function on the prostate. DHT has the highest binding affinity for SHBG of any substance, even of testosterone and estrogen. Because it does have the highest binding capacity for SHBG on prostate cells and is most closely associated with the development of prostate enlargement, as testosterone is selectively converted more into DHT as men age, this may lead to and exacerbate BPH.
One of the most destructive effects of aging is the loss of muscle and bone mass. While the loss of bone mass, or osteoporosis, is now widely recognized as a significant factor in robbing elderly women of their ability to walk, osteoporosis is also a significant health concern for older men. In addition, the loss of muscle tissue, or sarcopenia, is now finally being recognized as a major debilitator of both men and women. In men, both sarcopenia and osteoporosis can be linked to the decline in testosterone and other steroid hormones.
A study of 403 healthy men aged 73-to-94 years, in the Journal of Endocrinology and Metabolism examined the hypothesis that the decreases in muscle strength, bone mass and body composition seen in aging males are related to falling testosterone levels. The researchers measured the men’s hormonal levels and ran multiple tests to gauge their body composition, muscle strength and bone mass. Their findings were that muscle strength and bone mass were at optimal levels in men with the highest levels of free testosterone, leading the authors to state that there are a number of clinical problems present in older men that may be related to testosterone deficiency, including reduced muscle mass, changes in body composition, and loss of bone mass density.
Another study in the Journal of Endocrinology and Metabolism showed that older men with total testosterone or estrogen deficiency were more likely to be osteoporotic and those with osteoporosis were more likely to be testosterone or estrogen deficient. Subsequently rapid bone loss in the hip joint, one of the most commonly fractured joints in the elderly, was more likely to be observed in men with total testosterone deficiency.