A prospective study of initially healthy women aged 45 and over found that smoking is a potent risk factor for symptomatic peripheral artery disease, or PAD. PAD is a serious, often debilitating disorder, caused by narrowing of the arteries in the lower extremities. Symptoms of PAD include pain in the legs with normal activity and a feeling of tiredness in the leg muscles.

Researchers followed 38,825 women for an average of 12.7 years to determine if smoking increased a woman's risk for PAD and if smoking cessation reduced that risk. The women were questioned about their smoking history and if they currently smoked cigarettes. If so, they were asked to disclose how many they smoked per day. During the course of the study, patients periodically filled out questionnaires about their health and smoking habits. Surveys were given twice during the first year and then once per year for the remainder of the study and follow-up period. Participants were asked to report any symptoms of PAD.

The researchers found that smoking increased a woman's risk for PAD 10-fold. Smoking cessation reduced the risk, but even after abstaining from cigarettes for 20 years, the risk did not lower to that of a woman who had never smoked.

"This study showed that -- as has been previously shown for heart attacks and for lung cancer -- that smoking is actually very harmful for the development PAD," said Eruna Pradhan, Assistant Professor of Medicine at Harvard Medical School and an author of the study. "This is significant because PAD is a disease that not only causes a lot of pain and discomfort with usual, daily activities but it also increases the risk of heart attack."

The study was published in the June 7 issue of Annals of Internal Medicine.