Eating disorders may be contagious: study

NEW YORK (Reuters Health) - A study of U.S. high school students provides additional evidence that eating disorders may be contagious.

In a study, researchers found that binging, fasting, diet pill use and other eating disorder symptoms clustered within counties, particularly among female students.

"These findings confirm the strong social influences on female adolescents in the U.S. to be thin, sometimes using unhealthy behaviors to achieve this goal," the researchers write in the current issue of the International Journal of Eating Disorders.

Research in the 1980s in female college students first suggested that disordered eating behavior spread through "social contagion," demonstrating that binge eating clustered within sororities, Dr. Valerie L. Forman-Hoffman and Cassie L. Cunningham of the VA Iowa City Health Care System note in their report.

In the current study, they looked at whether a similar pattern would be seen among high school students at the county-wide level by analyzing nationally representative data on 15,349 high school students.

There was indeed a small but significant clustering effect, the researchers found. A pair of students from the same county was 4 percent to 10 percent more likely to share an eating-disordered behavior when compared to pairs in which each person came from a different county.

Severe food intake restriction, dieting, exercising and diet pill use all showed clustering by county, as did any weight control symptom overall or any eating disorder symptom. But no clustering was seen for purging, possibly due to the "secretive," less socially acceptable nature of this behavior, the researchers suggest.

Clustering patterns were the same in rural, suburban and urban counties.

While the study wasn't designed to look at why these behaviors might be clustering in certain counties, the researchers suggest that peer pressure, information sharing or students modeling their behavior on one another are possible mechanisms.

Based on their results, the researchers think it may be more effective to target eating disorder prevention efforts to counties or schools where they are more common, rather than individual students.

SOURCE: International Journal of Eating Disorders, April 2008.