Those who smoke or have a history of smoking have up to four times greater risk of PAD. Exposure to tobacco raises the risk of atherosclerosis by constricting arteries and promoting inflammation.
In a study conducted by Harvard University, researchers reported that smokers whose lifetime exposure to cigarettes was 10 to 29 pack-years were six times more likely to develop PAD (compared to non-smokers). Additionally, those with a lifetime exposure of thirty or more pack-years had eleven times the risk. (A pack-year is a measure of tobacco exposure: one pack of cigarettes a day for ten years, two packs a day for five years, and half a pack a day for 20 years each adds up to ten pack-years.)