MONDAY, April 5, 2010 (Health.com) — If a friend or relative starts drinking more heavily—or decides to drink less or give up alcohol entirely—you’re more likely to do the same, according to a new study that found heavy drinkers, moderate drinkers, and teetotalers tend to cluster within social networks.
People don’t give up bad habits because they think, “Oh, this is bad, I shouldn’t do it,” says Tim Naimi, MD, a physician at Boston Medical Center who studies the public health aspects of alcohol but wasn’t involved in the new study. “It’s largely because they feel their friends and neighbors will look down on them.”
The closer the social connection, the greater the influence one person’s drinking had on another’s, the researchers found.
People were 50% more likely to be heavy drinkers if one of their friends or relatives drank heavily. However, if a friend-of-a-friend drank heavily, people were only 36% more likely to do so, and if a friend-of-a-friend-of-a-friend drank heavily, they were 15% more likely to do so. (Women were classified as heavy drinkers if they averaged more than one drink a day; for men, it was two drinks.)
The pattern worked in reverse, too, although it wasn’t as pronounced. People with a friend or relative who didn’t drink were 29% more likely to be teetotalers themselves.
The quantity of relationships mattered as well. The more connections to drinkers—or nondrinkers—a person had, the more powerful the effect was. People “surrounded by” heavy drinkers were 70% more likely to drink heavily themselves, while those with many abstinent friends and relatives were 50% more likely to also abstain, according to the study.
When it comes to drinking, friends and family members appear to have the biggest influence on us. The study found that the drinking habits of a person’s co-workers or neighbors had no effect on their own alcohol use.
In the study, which was published this week in the Annals of Internal Medicine, the researchers followed about 12,000 men and women for more than 30 years. The participants—who listed their social contacts when they enrolled in the study in 1971, and at several points thereafter—are part of the Framingham Heart Study, a large longitudinal study that has examined heart disease risk factors in that Massachusetts town since 1948.
Next page: Other behaviors are contagious too