The narrowing of the blood vessels in the legs and, less commonly, in the arms. Blood flow is restricted, with pain (claudication) occurring in the affected area. If the blood supply is seriously reduced, GANGRENE of the tissues supplied by the affected vessel(s) may occur and the limb may need to be amputated. The common cause is ATHEROSCLEROSIS which may be brought on by HYPERTENSION, excessively fatty diet, poorly controlled DIABETES MELLITUS or smoking – the latter being the biggest risk factor, with 90 per cent of affected patients having been moderate to heavy smokers. Stopping smoking is essential; adequate exercise and a low-fat diet are important measures. Surgery may be required.