The etiology of ED is usually multifactorial. Organic, physiologic, endocrine, and psychogenic factors are involved in the ability to obtain and maintain erections. In general, ED is divided into organic and psychogenic impotence, but most men with organic etiologies usually have an associated psychogenic component. Almost any disease may affect erectile function by altering the nervous, vascular, or hormonal systems. Various diseases may produce changes in the smooth muscle tissue of the corpora cavernosa or influence the patient's psychologic mood and behavior. Pure psychogenic ED is an uncommon disorder, although most ED was once attributed to psychological factors.
Diabetes is a well-recognized risk factor, with approximately 50% of diabetic men experiencing ED. The etiology of ED in diabetic men probably involves both vascular and neurogenic mechanisms. Evidence indicates that establishing good glycemic control can minimize this risk.
To a healthy young man, erectile dysfunction (ED) may seem unthinkable. You can probably remember times (think back to high school) when you wished it wasn't so easy to get an erection.
But as you age -- and especially when you have diabetes -- you may notice some changes. Maybe it takes more coaxing to get erect than it used to. Sometimes it may take more direct stimulation of the penis, whereas merely a daydream or the suggestion of sex was once enough. Or perhaps your erections aren't quite as...
Cigarette smoking has been shown to be an independent risk factor. In studies evaluating more than 6000 men, the risk of developing ED increased by a factor of 1.5
Mental health disorders, particularly depression, are likely to affect sexual performance. The MMAS data indicate an odds ratio of 1.82. Other associated factors, both cognitive and behavioral, may contribute. Also, ED alone can induce depression. The new oral agents have been shown to be effective for men who develop depression following prostatectomy.
Cosgrove et al have reported a higher rate of sexual dysfunction in veterans with posttraumatic stress syndrome than in those veterans who did not develop this problem. The domains on the IIEF questionnaire that demonstrated the most change included overall sexual satisfaction and erectile function. This study suggests that regardless of etiology, men with posttraumatic stress syndrome should be evaluated and treated if they have sexual dysfunction.
A sedentary lifestyle is a contributing factor to ED. Exercise has a beneficial effect on the cardiovascular system, and some data from the MMAS indicate that men who exercise regularly have a lower risk of ED. However, Goldstein et al reported an increased risk of ED in men who rode a bicycle for long periods. Therefore, the type of exercise may be important.
The MMAS study also showed an inverse correlation between ED risk and high-density lipoprotein cholesterol levels but no effect from elevated total cholesterol levels. Another study involving male subjects aged 45-54 years found a correlation with abnormal high-density lipoprotein cholesterol levels but also found a correlation with elevated total cholesterol levels. The MMAS study had a preponderance of older men.
Vascular diseases account for nearly half of all cases of ED in men older than 50 years. Vascular diseases include atherosclerosis, peripheral vascular disease, myocardial infarction, and arterial hypertension.
Vascular damage may accompany radiation therapy to the pelvis and prostate in the treatment of prostatic cancer. In this situation, both the blood vessels and the nerves to the penis may be affected. Radiation damage to the crura of the penis, which are quite susceptible to radiation damage, can induce ED. The radiation oncologist must take precautions to avoid treating this area. Data indicate that 50% of men undergoing radiation therapy lose erectile function within 5 years after completing therapy. Fortunately, some of these men tend to respond to one of the PDE-5 inhibitors.