Just as smokers often stick together socially, new research suggests that they also tend to quit together. The study, published in the May 22 issue of the New England Journal of Medicine, found that rather than quitting alone, smokers are more likely to quit smoking when they are part of a social network of smokers who are also kicking the habit.

It is purely the closeness of the personal relationships between smokers that plays a central role in cessation.

Researchers tracked 12,067 individuals — both smokers and non-smokers — over 32 years. Participants were part of the multi-generational Framingham Heart Study and formed a large social network of various relationships.

Investigators found that the closer the relationship between individuals, the more likely one was to quit smoking. That is, when one's spouse quit, the likelihood of an individual continuing to smoke was decreased by 67%; when a friend quit, chances were lessened by 36%; when a sibling gave up smoking, the likelihood dropped by 25%; and in small business firms, a coworker quitting decreased one's odds of smoking by 34%. Interestingly, this drop was not found in larger places of business or among neighbors. These results suggest that there is no geographical component to the trend; it is purely the closeness of the personal relationships between smokers that plays a central role in cessation.

The position of smokers in their social groups has also changed over time: in 1971, smokers and non-smokers tended to blend socially, whereas in 2000, the two groups were often part of separate social crowds. Even more interesting is that nowadays, smokers are usually found on the periphery of their social networks — rather than in the center, as was the case in 1971.

What does this mean for quitting techniques? The researchers suggest that the cluster effect may be useful to changing behavior in a variety of ways, including a shift in the ways smokers are targeted in advertising and public health campaigns.