Smokers are becoming marginalised in the US

When researchers first began the Framingham heart study back in 1948, they asked participants for the contact details of close friends to help them keep track of the cohort. More than half a century later, other researchers are using these incidental data to study the spread of behaviours such as smoking through social networks⇑.

The latest study, analysing data between 1971 (the children of the original cohort) and 2000, makes it clear that as the prevalence of smoking falls smokers are becoming increasingly marginalised. By 2000, they tended to cluster at the edge of social networks and associate mainly with other smokers. The same network analysis shows that groups of smokers seem to quit roughly at the same time, and that spouses, siblings, friends, and colleagues can all influence a person to quit smoking. Having a spouse who quit decreased a person’s chance of smoking by 67% (95% CI 59% to 73%), for example. Friends and close colleagues in small firms helped …