Some 30% to 75% of men with diabetes complain of ED, and conversely, statistics show that about one out of four men with ED has diabetes; in fact, a finding of ED may even lead to the initial discovery of a man's diabetes. In one study, ED was the first sign of diabetes in 12% of the study group, and 50% of the diabetics developed ED within 10 years of their diabetes diagnosis.
Sexual dysfunction in diabetics has been found to be age-dependent, with ED affecting 15% of those aged 30 - 34, versus about 55% of 60-year-old diabetics. Type 2 diabetes, which usually occurs in older people and is due to insulin resistance, is associated with a higher incidence of ED than the hereditary type 1.
Recent electron microscope studies in diabetic men with ED revealed pathologic changes in the nerves and smooth muscles of the cavernous tissue and penile arteries. Impaired smooth muscle relaxation in the corpora cavernosa was demonstrated in cases of ED by researchers at Boston University Medical Center. In addition, recent studies indicate that diabetes and high cholesterol may prevent full relaxation of the trabecular smooth muscle in the penile vascular sinuses, with clogging of small intrapenile arteries in the cavernous tissue, which may lead to ED.
Additional causes of ED in men with diabetes include blood hypercoagulability, secretion of vasoconstrictive substances, and replacement of smooth muscle by collagen in the corpora. Recent studies have discovered new etiologic factors that may play a major role in the sexual impairment of diabetic patients, including endothelial dysfunction, oxidative stress, neuropathy, and structural changes.