For many otherwise healthy men, impotence can be an infrequent source of embarrassment and mild concern. But for some men with diabetes, impotence is a painful fact of daily life. The cause: diabetic neuropathy, a nerve disorder that can disrupt the neural pathways responsible for creating and sustaining an erection.

Neuropathy derails the brain signals that would normally speed along the nerves from the spinal cord to the erectile tissue of the penis. These nerve messages normally release nitric oxide, a chemical that relaxes arteries in the penis, which allows increased blood flow and makes erection possible. Neuropathy also disrupts the "erection messages" that are sent from the penis to the brain—for example, during physical stimulation of the penis.

In other words: a communication breakdown. And that means no sex.

According to the National Diabetes Information Clearinghouse, diabetic neuropathy can occur at any time, although the chances of it developing rise the longer a person has diabetes. It usually develops over a period of years and initially shows no symptoms. The risk of neuropathy appears to be more common in smokers, people over age 40, and those who have had problems controlling their blood glucose levels. Researchers believe that diabetic neuropathy is likely caused by a combination of factors including: metabolic problems (eg, high blood glucose), damage to blood vessels, genetics, and lifestyle factors (eg, smoking, alcohol use).