PAD affects about 8 million Americans. It is often a serious, debilitating disorder caused by narrowing of the arteries in the lower extremities. PAD not only causes pain in the legs but is also associated with an increased risk of heart attack, according to new research.
In a Harvard Medical School study, researchers followed 38,825 initially healthy women over age 45 for an average of 12.7 years to determine if smoking was a significant risk factor for development of PAD.
The researchers found that smoking increased a woman's risk for PAD tenfold. Quitting smoking reduced the odds of developing PAD but did not eliminate it, even for people who had given up cigarettes for many years.
Indeed, researchers found that not smoking for 20 years did not reduce the risk of development of PAD to the level of women who never smoked.
"This study showed that -- as has been previously shown for heart attacks and for lung cancer -- smoking is actually very harmful for the development of PAD," Eruna Pradhan, MD, of Harvard Medical School, says in a news release. "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."
Women in the study were questioned about their smoking history and current habit, if they still smoked, in which case they were asked to disclose how much.
Surveys were given twice during the first year and then once annually for the rest of the study and follow-up period. Participants were asked to report any symptoms of PAD, which includes pain in the legs and also feelings of tiredness in leg muscles.
A key finding of the study was that women who had never smoked had a "very low incidence" of PAD symptoms.
The more cigarettes a woman smoked per day, the more likely she was to develop PAD. The longer it had been since a woman stopped smoking, the less likely she was to have PAD. But no matter how long it had been since quitting, the risk remained higher than for those who had not smoked.
The researchers point out that despite reductions in smoking prevalence in recent years, 18.2% of women still use cigarettes in the U.S. And prevalence is even higher in European countries.
The study is published in the June issue of Annals of Internal Medicine.