Academic Minute
5:00 am
Thu October 18, 2012

Dr. David Shoham, Loyola University of Chicago – Obesity and Peer Groups

In today’s Academic Minute, Dr. David Shoham of Loyola University of Chicago reveals how an adolescent’s circle of friends can influence their weight and health.

David Shoham is an assistant professor of epidemiology at the Loyola University of Chicago Stritch School of Medicine where his research seeks to understand the social determinants of obesity. His current project focuses on peer, family, neighborhood, and school influences on childhood obesity using social network analysis. His findings have been published in a number of peer-reviewed journals and he holds a Ph.D. from the University of North Carolina at Chapel Hill.

About Dr. Shoham

Dr. David Shoham – Obesity and Peer Groups

Childhood obesity has become an epidemic in America. About 18 percent of adolescents aged 12 to 19 are obese, compared with less than 11 percent in 1988-1994. To reverse this alarming increase, researchers have tried many prevention strategies that target individuals, including educating children on healthy eating, physical activity and restricting screen time. Unfortunately, most of these interventions have had, at best, modest results.

An emerging body of research suggests that rather than treating adolescents in isolation, we also should take into account their circle of friends. For example, my colleagues and I recently published a study of high school students that found that a student's friends had a significant effect on the student's body mass index (a measure of body fat). If a borderline overweight student had lean friends, there was a 40 percent chance the student's body mass index would drop in the future, and a 27 percent chance it would increase. But if a borderline overweight student had obese friends, there was a 15 percent chance the student's body mass index would decrease and a 56 percent chance it would increase.

We analyzed data from two large high schools that participated in the National Longitudinal Study of Adolescent Health, known as Add Health. Our findings were published in the journal PLoS ONE. We found that part of the reason why obesity clusters in social networks is simply due to the "birds-of-a-feather-flock-together" effect -- lean kids tend to select lean friends, and heavy kids tend to select heavy friends. But even after controlling for this friend-selecting process, we still found a significant link between obesity and a student's circle of friends.

Our study had several limitations, and of course no one study can be considered conclusive. But with more research, we hope to devise effective new ways to fight childhood obesity.

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