ATLANTA — Quitting smoking can turn back time.
A year after kicking the habit, smokers' arteries showed signs of reversing a problem that can set the stage for heart disease, according to the first big study to test this.
The improvement came even though smokers gained an average of 9 pounds (4 kilograms) after they quit, researchers found. Their levels of so-called good cholesterol improved, too.
"A lot of people are afraid to quit smoking because they're afraid to gain weight," said the study's leader, Dr. James Stein, a University of Wisconsin-Madison cardiologist.
The new research shows these people gain a health benefit even though they pick up pounds that hopefully can be shed once they've gotten used to not smoking, he said.
Smoking is one of the top causes of heart disease, and about one third of smoking-related deaths in the U.S. are due to heart disease. A heart attack often motivates longtime smokers to give it up.
Quitting is known to lower the risk of developing or dying of lung cancer. This is the first major clinical trial to show it quickly improves artery health. Results were published in the Journal of the American College of Cardiology and presented at the group's annual conference on Monday.
In the study, 1,500 smokers were given one of five methods to help them quit — nicotine patches; nicotine lozenges; the drug bupropion, sold as Wellbutrin and Zyban; or a combination of patches and lozenges or the drug and lozenges. A sixth group received a dummy treatment.
After one year, 36 percent had quit, and it made no difference which method they used, Stein said.
Before the study started and one year after smokers quit, doctors did ultrasound tests to see how well blood vessel linings relaxed and handled blood flow. Hardening of the arteries is an early step to heart disease. Using a tourniquet, they stopped blood flow in the forearm for a few minutes, then measured how a major artery responded when the flow was restored.
"It's a valid test" and is considered a good sign of how healthy the heart arteries are, said Dr. Alfred Bove, a Temple University heart specialist and president of the cardiology group.
Doctors found that artery function improved 1 percent in the quitters.
"That may not sound like much," but research shows that translates to a 14 percent lower risk of developing heart disease, Stein said.
"It's a small improvement at one year. The question is, do these folks keep getting better?" Bove said.
The study is continuing another two years to give an answer, Stein said.
London-based GlaxoSmithKline PLC provided smoking cessation medicines for that part of the study, and several authors have research funding from the company. Federal government grants paid for the artery study.