Too Much Alcohol? Friends May Be to Blame

April 5, 2010 -- The people you hang out with play a big role in determining how much booze you drink -- or if you drink alcohol at all.

The finding comes from a study based on data mined from the Framingham Heart Study, which followed 12,067 people for more than 30 years, looking at lifestyle habits for clues to the causes of various diseases.

Researchers examined self-reported alcohol intake and looked at the drinking habits of their social contacts.

A key finding was that a person is 50% more likely to drink heavily if they are directly connected to a heavy drinker. And the researchers found that a person is 36% more likely to drink heavily if a friend of a friend is a heavy drinker.

“We’ve found that the influence of your friends and people you have connections with can affect your health just as much as your family history or your genetic background,” Nicholas Christakis, MD, PhD, professor of medicine at Harvard University, says in a news release. “With regard to alcohol consumption, your social network may have both positive and negative health consequences, depending on the circumstances.”

In the study, self-reported alcohol intake over time followed changes in the alcohol intake of the respondents’ social contacts.

The researchers say this social phenomena could have other implications for clinical and health interventions. For instance, social networks could be used to exploit positive health behaviors and further support group interventions.

“Our findings reinforce the idea that drinking is a public health and clinical problem that involves groups of interconnected people who evince shared behaviors,” says Christakis, author of the study. “In treating individuals for problematic drinking, we need to look at their social networks to identify and eliminate obstacles to abstaining.”

Social Networks Affect Drinking Habits

Participants in the Framingham study were asked periodically between 1971 and 2003 how much alcohol they drank. Then they looked for patterns between how much a person drank and how much his or her social contacts imbibed.

Among the findings:

• Drinkers were more likely to have social contacts who drank similar amounts.
• Nondrinkers were more likely to have friends and relatives who didn’t drink.
• The drinking habits of neighbors and co-workers weren’t as strongly associated with a person’s drinking habits, compared to friends and relatives.

The researchers say the study is important because the amount of alcohol people drink influences their health.

How often people drink and the amount can also depend on genes and other biological factors.

But the social factors, the researchers say, explain why parents often worry if they think their children have friends who drink.

Recent research also has shown that smoking, obesity, and sexually transmitted diseases also travel in social networks.

According to the study:

• 55% of adults reported in 2002 that they had at least one drink in the previous month.
• 62% of men gave that answer; 48% of women.
• A friend or family member is as likely to sway a person one way or another whether he or she lives hundreds of miles away or next door.
• Heavy drinking by husbands and wives increases the odds that spouses will drink heavily, too.
• Female contacts are significantly more likely than males to influence the spread of heavy alcohol consumption.