Diabetes can cause peripheral artery disease, or PAD, which inhibits loss of blood flow, making it easier for infections in the extremities to progress to gangrene, according to WebMD. Any medical condition that hinders the flow of blood throughout the body can lead to gangrene.
As a result of diabetes, blood vessels in the leg and foot harden and narrow, explains the American Diabetes Association. While exercise can ameliorate this condition, stimulating blood flow in the feet and legs, it is important to use shoes that are sturdy and fit well. People who have open sores should not exercise until the sores have healed.
In addition to PAD, many diabetics also develop nerve disease, which cuts down on sensation, notes the American Diabetes Association. These problems combine to make ulcers and infections easier to develop, as patients do not always notice the pain from their feet and so do not treat the sores adequately. If gangrene develops, one possible consequence is amputation of some or all of the affected limb. With regular maintenance and correct footwear, the majority of amputations are preventable, but this requires diabetics to remain vigilant about the state of their feet. People who smoke damage their small blood vessels even further, and many diabetics who need amputations smoke as well. Quitting smoking can preserve one's feet.