Spouses, friends, siblings and co-workers usually decide to light up or stub out their cigarettes for good at around the same time, a new study has found. A better understanding of how social ties affect smoking behavior may lead to more effective ways to prevent or reduce smoking.
While smoking rates have fallen over the past 4 decades, it remains the leading cause of preventable death in the United States. Previous studies have shown that social ties between 2 people—especially young people—can influence decisions to start or stop smoking. But the effects of more complex social groups have been unclear.
NIH-funded researchers at Harvard Medical School and the University of California, San Diego examined medical records and other data from more than 12,000 adults who had participated in the Framingham Heart Study, a long-term study sponsored by NIH. The researchers were able to track changes in social relationships over more than 3 decades, from 1971 to 2003, because people in the study regularly updated information about their family, friends and coworkers.
At the beginning of the study, smokers tended to mix equally with nonsmokers. By 2000, smoking in the group had declined, mirroring the national downward trend. There was also another change. The smokers and nonsmokers divided into separate clusters as the study progressed. Eventually, the smokers were on the fringes of the network, with fewer social ties to others.
Close relationships seemed to exert a strong influence on smoking. The greatest effect was in married couples. When a husband or wife quit smoking, it reduced the chance of their spouse smoking by about 67%. When a sibling quit, it reduced the chance of smoking in a brother or sister by 25%. Influences from friends and coworkers fell in between.
Last year, the scientists reported on the spread of obesity within the same study group. This research suggests that it may be possible to harness social networks to help people change behaviors that affect their health, such as smoking, for the better.