Yang, Muzhe (2010). Exposure to obesity and weight gain among adolescents. 2010 Add Health Users Conference.
In a treatment-effect framework using Add Health data, we investigate whether adolescents gain weight when increasingly exposed to obesity in their social networks. In this paper, we have assembled a set of empirical evidence that supports an effect of increased exposure to obesity on weight gain within a social network. Based on Wave I and Wave II of the Add Health surveys, we find that adolescents who experience an increase in the number of obese friends over a one to two-year period subsequently can gain more weight, approximately 0.8-0.9 BMI, relative to a control group for whom there is no change in the number of obese friends over time. That increase in BMI corresponds to approximately 5 to 6 pounds for an adolescent with an average height of 5.5-5.6 feet. Specifically, the effect on weight gain of an increased exposure to obesity seems to exist mostly among those who are neither obese nor overweight at the beginning (in Wave I). Our study also provides evidence to support that the increased exposure to obesity causes weight gain through social ties rather than geographic proximity. Our study suggests that it may be an uphill battle against the obesity epidemic. Policies focused on the prevention of obesity probably should receive a high priority.
2010 Add Health Users Conference
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