NEW YORK – Women who smoke are much more likely than non-smokers to develop clogged arteries in the legs—but quitting can lower those odds, according to a study published Monday.
The study, reported in the Annals of Internal Medicine, found that female smokers were up to 17 times more likely than non-smokers to develop peripheral artery disease (PAD).
About 8 million Americans have PAD, which usually arises when atherosclerosis, a hardening and narrowing of the arteries, restricts blood flow to the legs. The main symptom is leg pain or cramps during normal activities, like walking, though not everyone with the condition has symptoms.
People with PAD often have widespread atherosclerosis, including coronary heart disease—where arteries feeding the heart become narrowed and stiff. For some, leg pain is the first symptom of wider problems.
Smoking has a well-established link to heart disease. But fewer studies have focused on PAD.
The good news from the current study is that women who kicked the habit appeared to lower their risk of PAD—though they did not eliminate it.
"Our most important finding, in my view, is that smoking cessation substantially reduces this risk," said lead researcher Dr. David Conen, of the University Hospital Basel in Switzerland.
"We found a gradual decrease in risk with an increased duration of smoking abstinence, highlighting the importance of smoking cessation," Conen told Reuters Health in an email.
Compared with lifelong non-smokers, former smokers had three times the risk of developing PAD over 13 years.
But current smokers showed much higher odds: those who smoked fewer than 15 cigarettes a day had a nine-fold higher risk of PAD than lifelong non-smokers, while those who lit up more often had a 17-times higher risk.
"Clearly, our study adds one more reason to quit smoking as soon as possible," Conen said.
However, he added, "the fact that the risk of PAD does not get down to that of women who never smoked also emphasizes the importance that never starting smoking is at least as important."
The findings come from a long-running study of U.S. women who were age 45 or older and free of heart disease and other major health problems at the outset. Of nearly 40,000 women followed for 13 years, 178 were eventually diagnosed with PAD.
Among the heaviest smokers—15 or more cigarettes per day—PAD was diagnosed at a rate of 1.6 cases for every 1,000 women each year. Among lifelong non-smokers, there were 0.1 cases for every 1,000 women each year.
When Conen's team accounted for other PAD risk factors, like older age, obesity and diabetes, smoking itself was still strongly linked to the disease.
The researchers also gained some clues as to why smoking might lead to PAD. Based on blood samples from a subgroup of women, high levels of certain inflammatory proteins accounted for some of the risk linked to smoking.
That, Conen's team says, suggests that smoking leads to PAD, in part, by spurring chronic inflammation in the blood vessels.
He suggested that doctors be careful to look for signs and symptoms of PAD in patients who smoke.
Besides leg pain during exercise, other signs include leg sores that don't heal, feelings of cold or numbness in the legs or feet, and hair loss or slowed hair growth on the legs.
Once PAD is diagnosed, treatment usually involves lifestyle changes to improve a person's overall cardiovascular health, including a healthy diet and regular exercise. People with PAD may also take aspirin or other medications to prevent blood clots.
In cases where leg pain is debilitating, doctors may prescribe medications that improve blood flow to the legs. Some people end up needing angioplasty or bypass surgery to take care of blockages in the leg arteries.