The association of CVD and ED was noted in 1997 as one analysed the results of the MMAS. In this landmark study, 1709 men aged 40–70 years were enrolled between 1987 and 1989. A follow-up some 10 years later revealed a striking relationship between ED and CVD. In this study, it became clear that the risk factors for ED were very similar to those of CVD, such as diabetes mellitus, smoking and dyslipidaemia.18
First, medical conditions need to be ruled out. Let’s assume that you have never been diagnosed with a medical condition that is physically linked to erectile dysfunction, such as type 2 diabetes, obesity or heart disease. In this case you’re probably looking at a case of psychological impotence, given that there are no physical explanations for your difficulties.
Talk with your doctor about going to a counselor if psychological or emotional issues are affecting your ED. A counselor can teach you how to lower your anxiety or stress related to sex. Your counselor may suggest that you bring your partner to counseling sessions to learn how to support you. As you work on relieving your anxiety or stress, a doctor can focus on treating the physical causes of ED.
Vascular damage may result from radiation therapy to the pelvis and prostate in the treatment of prostate cancer.  Both the blood vessels and the nerves to the penis may be affected. Radiation damage to the crura of the penis, which are highly susceptible to radiation damage, can induce ED. Data indicate that 50% of men undergoing radiation therapy lose erectile function within 5 years after completing therapy; fortunately, some respond to one of the PDE5 inhibitors.
In a randomized double-blind, parallel, placebo-controlled trial, sildenafil plus testosterone was not superior to sildenafil plus placebo in improving erectile function in men with ED and low testosterone levels.  The objective of the study was to determine whether the addition of testosterone to sildenafil therapy improves erectile response in men with ED and low testosterone levels.
A larger national study, the National Health and Social Life Survey, looked at sexual function in men and women.4 This study surveyed 1,410 men aged 18 to 59 and also documented an increase in ED with age. Additionally, the study found a decrease in sexual desire with increasing age. Men in the oldest cohort (50 to 59) were more than 3 times as likely to experience erection problems and to report low sexual desire compared with men 18 to 29. Experience of sexual dysfunction was more likely among men in poor physical and emotional health. The study also concluded that sexual dysfunction is an important public health concern and that emotional issues are likely to contribute to the experience sexual dysfunction.
The link between chronic disease and ED is most striking for diabetes. Men who have diabetes are two to three times more likely to have erectile dysfunction than men who do not have diabetes. Among men with erectile dysfunction, those with diabetes may experience the problem as much as 10 to 15 years earlier than men without diabetes. Yet evidence shows that good blood sugar control can minimize this risk. Other conditions that may cause ED include cardiovascular disease, atherosclerosis (hardening of the arteries), kidney disease, and multiple sclerosis. These illnesses can impair blood flow or nerve impulses throughout the body.
For best results, men with ED take these pills about an hour or two before having sex. The drugs require normal nerve function to the penis. PDE5 inhibitors improve on normal erectile responses helping blood flow into the penis. Use these drugs as directed. About 7 out of 10 men do well and have better erections. Response rates are lower for Diabetics and cancer patients.