Sexual dysfunction in patients with diabetes often involves a type of nerve disease (diabetic neuropathy) called autonomic neuropathy. Uncontrolled glucose (blood sugar) is believed to be the leading cause of this nerve damage.

Autonomic neuropathy affects the autonomic nervous system (ANS), which is responsible for regulating the involuntary or subconscious systems of the body, such as digestion, blood flow and bladder control. The ANS also controls the body's response to sexual stimuli. When an individual becomes sexually aroused, the autonomic nerves signal the body to increase blood flow to the genitals, which, in turn, promotes relaxation of the smooth muscle tissue. Damage to the autonomic nerves by neuropathy can impede normal sexual function, preventing the penis from becoming firm and preventing the vagina from becoming properly lubricated before and during intercourse.

Diabetic sexual dysfunction can also stem from vascular (blood vessel) disease, which typically also involves poor control of glucose. This diabetic angiopathy is characterized by the steady accumulation of fatty deposits (plaque) on the inner arterial walls (atherosclerosis). These fatty deposits can decrease the flow of blood to the penis and make achieving or maintaining an erection difficult or impossible. Sexual dysfunction in men may be a harbinger of the developement of coronary artery disease. In women, vascular damage can impair arousal by restricting blood flow to the genitals.

Other conditions related to diabetes that may contribute to autonomic neuropathy and vascular disease (and result in sexual dysfunction) include:

• High blood pressure (hypertension)
• Unhealthy levels of cholesterol
• Obesity or overweight
• Fatigue
• Inactivity
• Kidney disease (diabetic nephropathy)

Additional issues that may affect sexual functioning of people with diabetes include:

• Urologic (relating to the urinary tract) conditions. Individuals with poorly controlled diabetes are prone to certain urologic conditions, which can cause discomfort and impact sexual intercourse. These conditions may include:
  
  
• • Overactive bladder
  • Neurogenic bladder (loss of normal bladder function due to nerve damage)
  • Urinary tract infection (UTI)
  • Yeast infection (common among women)

Individuals with diabetes and a UTI or yeast infection should refrain from sexual activity during treatment of these conditions.

• Hormone disorders. A low level of testosterone (male hypogonadism), which reduces the sex drive, is common in diabetic men. Women can experience low levels of female sex hormones caused by disorders of the pituitary gland or ovaries. In addition, polycystic ovarian syndrome, in which the ovaries release high levels of male-type hormones, involves insulin resistance and increases the risk of type 2 diabetes in women.
  
  
• Sexually transmitted diseases (STDs). Individuals with diabetes are prone to certain types of skin conditions, such as dry, cracked skin, which may increase the risk of STDs. Thus, it is particularly important for people with diabetes to practice safe sex.
  
  
• Hyperglycemia. In addition to contributing to autonomic neuropathy and vascular disease, excess glucose levels in the blood can reduce testosterone and may contribute to diminished sexual interest.
  
  
• Cancer. Diabetes increases the risk of several types of cancer, including some that can affect sexual functioning. These include colorectal cancer, endometrial cancer, cervical cancer and possibly prostate cancer. Treatments for these tumors can also affect sexual function and in some cases could impede diabetic control (e.g., hormone therapy for prostate cancer may increase insulin resistance).

Other potential causes of sexual dysfunction not necessarily associated with diabetes include:

• Depression, stress, anxiety or other psychological factors
• Abuse of alcohol or drugs
• Smoking
• Side effects of antihypertensives, antidepressants or other medications
• Menopause
• Prostate disorders such as benign prostatic hyperplasia (BPH)
• Pelvic trauma
• Stress and other psychological factors