New York: Researchers have found a strong link between smoking and peripheral artery disease -- a circulatory condition in which narrowed blood vessels reduce blood flow to the limbs -- and this elevated risk can persist up to 30 years after quitting smoking.
The study, led by researchers at the Johns Hopkins University's Bloomberg School of Public Health, also found that the link between smoking and peripheral artery disease was even stronger than that for coronary heart disease and stroke.
"The study suggests that campaigns about smoking's health risks should emphasize the elevated risk of peripheral artery disease, not just coronary heart disease and stroke," said senior study author Kunihiro Matsushita.
The study found that compared with never-smokers, those who smoked for more than 40 pack-years had roughly four times more risk for peripheral artery disease, versus 2.1 times and 1.8 times more risk for coronary heart disease and stroke, respectively.
A pack-year is a parameter of smoking -- 10 pack-years can mean one pack per day for 10 years or two packs per day for five years or some other combination.
Similarly, participants who reported currently smoking more than a pack per day had a relative increased risk -- 5.4 times more for peripheral artery disease versus 2.4 for coronary heart disease and 1.9 for stroke -- compared to those who had never smoked.
Peripheral artery disease features the atherosclerotic build-up of cholesterol-laden deposits in arteries serving the legs. The reduction of blood flow leads to limb pain, poor wound healing, and other signs and symptoms.
The effect of smoking on peripheral artery disease risk was not just stronger; it was also longer-lasting.
Only after 30 years of smoking cessation did the peripheral artery disease risk for former smokers return to the baseline level seen in never-smokers.
By comparison, coronary heart disease risk took about 20 years to return to baseline after smoking cessation.
The good news is that quitting smoking appeared to bring a meaningful drop in peripheral artery disease risk fairly quickly.
"We observed a lower risk for peripheral artery disease, coronary heart disease, and stroke within five years of smoking cessation," says Ning Ding, a data analyst and author of the study.
"Smoking almost always starts in adolescence or early adulthood, and it's very important that young people understand how long the elevated health risk persists even after they've quit," Matsushita noted.
The study, published in the Journal of the American College of Cardiology, is the first comprehensive comparison, in a large population moving through time, of the smoking-elevated risks of peripheral artery disease, coronary heart disease and stroke.
The analysis was based on a sample of 13,355 Atherosclerosis Risk in Communities (ARIC) cohort participants, including 3,323 current smokers and 4,185 former smokers, who were tracked for a median period of 26 years.