LOS ANGELES - The urge to smoke is contagious, but quitting apparently
is, too.
A team of researchers who showed that obesity can spread person-to-person has
found a similar pattern with smoking cessation: A smoker is more likely to kick
the habit if a spouse, friend, co-worker or sibling did.
What's more, smokers tend to quit in groups and those who don't stop puffing
increasingly find themselves pushed to the edge of their social circles, the
researchers found.
"Your smoking behaviour depends upon not just the smoking behaviour of the
people you know, but also the people who they know" and so on, said Dr. Nicholas
Christakis, a medical sociologist at Harvard Medical School and lead author of
the new report.
The findings back up previous studies showing that peer influence plays a key
role in people's decision to stop lighting up and provide evidence that the
"buddy system" used by smoking cessation, weight loss and alcoholism programs to
change addictive behaviour works.
"Anecdotally, we hear people say they quit smoking because their spouse or
friend quit," said Jennifer Unger, a smoking prevention expert at the University
of Southern California who had no role in the study. "If you influence a few
people, those people might go on to help others to quit."
Last year, Christakis and his colleague James Fowler of the University of
California, San Diego, published a study suggesting that obesity can spread
among friends, much like an infectious disease. The duo mined data from a large
social network of people who had been followed for three decades and found that
when one person gained weight, close friends tended to pack on the pounds, too.
Their latest study, which appears in Thursday's New England Journal of Medicine
and is funded by the National Institute on Aging, focused on people's smoking
habits in the same social network.
The researchers examined the social lives of 12,067 people in the Framingham
Heart Study, which has been tracking the health of residents of that Boston
suburb from 1971 to 2003. They were able to reconstruct people's ties to one
another since participants had to list contact information for their family,
friends, co-workers and neighbours so researchers would not lose track of them
over the years. The prevalence of smokers in the Framingham study over the years
mirrored national trends.
Not surprisingly, the greatest influence was seen in close relationships. When a
spouse stops smoking, the other partner is 67 per cent less likely to smoke.
Similarly, when a friend quits, the odds of the other continuing drops by 36 per
cent. The odds are similar among co-workers and siblings.
People who were connected to others by up to three degrees of separation were
also influenced. If one person quits, the odds of a person two degrees apart
stopping is 29 per cent. In a three-degree separation, the chances are 11 per
cent.
"One person in the group gets the motivation to quit and it starts to cascade
and ripple through the group," said Fowler.
Jill Palmer, 28, was a one-pack-a-day smoker until she checked into a cessation
program last year at the University of Wisconsin, Madison where she works. She
took nicotine gum and worked with a counsellor to set a "quit date."
Several days after Palmer went smoke-free, her husband threw away his last pack.
"It was spurred by my timing. He didn't want to be a smoker anymore," said
Palmer, who credits her non-smoking co-workers with persuading her to enrol in
the cessation program.
The researchers also found, by analyzing random samples of smoking clusters,
that whole groups became non-smokers over time. People who remained smokers
found themselves moving to the fringe of their social circles.
Stanley Wasserman, an Indiana University statistician who studies social
networks, noted that while the study was cleverly done, it does have its
limitations.
Wasserman said it's hard to tease out whether social influence is mainly
responsible for a whole group kicking the habit. Other factors such as public
bans on smoking or studies highlighting the harmful effects of smoking may also
play a role.
"You can't prove it with this data," he said. "You have to go to people and ask,
'Why did you stop smoking?"'
