Diabetes mellitus is one of the most common causes of erectile dysfunction. An estimated 15.7 million people in the United States have diabetes, including 7.5 million men. Type 2 diabetes, also called non-insulin-dependent diabetes mellitus, accounts for 90% – 95% of the cases of diabetes mellitus; type 1 diabetes, or insulin-dependent diabetes mellitus, accounts for 5% – 10%. The prevalence of erectile dysfunction in diabetes ranges from 35% – 75%. In men with treated diabetes mellitus in the Massachusetts Male Aging Study, the age-adjusted prevalence of complete erectile dysfunction (no erections at any time) was 28%, which was about three times higher than the prevalence of complete erectile dysfunction in the entire sample of men in the Massachusetts Male Aging Study.
The exact cause of erectile dysfunction in men with diabetes mellitus remains to be determined. One possible cause is the presence of certain chemicals associated with diabetes called glycosylated end-products, which have been shown to decrease the activity of nitric oxide in the body and may also affect the response of blood vessels to nitric oxide. Nitric oxide is important for the production of the neurotransmitter cGMP, which causes the relaxation of the smooth muscles in the penis and arteries to allow for increased blood flow into the penis, so anything that adversely affects nitric oxide might also interrupt cGMP production, and thus damage erectile function. There may also be a neurologic component to diabetes mellitus-related erectile dysfunction.
The incidence of erectile dysfunction is about 30% lower in type 2 diabetes mellitus than in type 1. In both type 1 and type 2 diabetics, fair or poor metabolic control is associated with an increased risk of erectile dysfunction. The frequency of erectile dysfunction also appears to be related to the duration of diabetes for both type 1 and type 2 diabetics. There is also a positive correlation between the presence of complications of diabetes (neuropathy, vascular diseases, retinopathy, and nephropathy) and the incidence of erectile dysfunction in both type 1 and type 2 diabetics. In type 1 diabetics, the risk of erectile dysfunction was higher in those with a higher body mass index.