Damage to Circulatory and Nervous Systems
People with diabetes, whether type 1 or type 2, have an increased risk of severe complications if the disease goes undiagnosed and untreated -- or if it is poorly managed. High blood glucose levels make it easier for blockages to form in the blood vessels that supply the heart, brain, and legs as well as the rest of the body. High blood glucose can also damage nerves, causing numbness and tingling -- especially in the legs and feet.