One More Reason to Quit Smoking: You'll Make New Friends, Study Finds

And, over several years, quitters were more likely to start new friendships with nonsmokers, the research found.

"I wouldn't say it's a surprise, but it's a welcome finding. It's good to have it documented by a study that quitting smoking will broaden your social circles," said Dr. Norman Edelman, senior medical consultant at the American Lung Association. He was not involved with the research, but reviewed its findings.

The study also confirmed what has been seen in previous research: People trying to quit who spend less time around smokers have the highest success rates over time.

The number of smokers in the United States has been declining for decades and is now at an all-time low, according to the U.S. Centers for Disease Control and Prevention. But about 17 percent of the American population still smokes, the CDC says.

That number is still too high, said one of the study's authors, Megan Piper. She's an associate director of research at the University of Wisconsin Center for Tobacco Research.

Piper said that people who want to quit smoking may fear that they will lose friends who continue to smoke.

"Smokers are afraid of losing their friends" to the nonsmoking world, Piper said, adding that until now, no one has really studied what happens to relationships when people quit smoking.

What is known, she said, is that people who quit tend to break off relationships with people who continue to smoke. The reasons they do this still need to be studied further, Piper said.

The initial study group included slightly more than 1,500 people participating in a smoking cessation program. They were from Milwaukee or Madison, Wis. All smoked at least 10 cigarettes per day.

They were randomly selected to receive medication, nicotine replacement products or a placebo. All were also given counseling to help them quit.

Nearly 700 smokers completed all of the study assessments. These occurred at the start of the study and then at one, two and three years after their target quit date. The average age of the study participants was 46 years, and about 60 percent were female.

During the three-year study period, nearly three-quarters of the study volunteers reported adding at least two new friends to their social circle.

People who quit found that they become more socially acceptable to a much wider group of people—nonsmokers, Piper said.

It doesn't happen immediately, though. "There is a vacuum for a while when people quit, and they tend to fill it" with other people and organizations, she explained.

Smokers who quit have more opportunities to spend time at smoke-free places, such as restaurants, bars, clubs and stores.

"In many social circles, it is totally unacceptable to smoke," Piper said. "We think it would be helpful for smokers who want to quit to think of this."