Body mass index and social interactions from adolescence to adulthood


Johxhe, Majlinda & Corrado, Luisa (2018). Body mass index and social interactions from adolescence to adulthood. 2018 Add Health Users Conference. Bethesda, MD.


This paper proposes a novel approach to address identification of social endogenous effects by generalizing the methods commonly used in standard dynamic panel data analysis to the peer effects setting. Our methodology shows how one can estimate peer effects free of the "reflection problem" in a dynamic context where individual-and group-specific unobservable effects are controlled for. We apply a dynamic linear-in-means model for analyzing the importance of social ties for body-weight-related behavior of US youth using Add Health Data. We show that the main drivers of body-weight-related behavior are habituation and imitation effects. For individuals who were normal-weight during adolescence habits seem to be slightly enforced by imitative behavior: in this instance, for any 1% increase in average BMI we expect about 0:72% increase in individual BMI, whereas the coefficient for past BMI is 0:41%. Imitation effects, instead, explain most of the variation in the Body Mass Index of individuals who were overweight and obese during adolescence, signaling the presence of a social multiplier effect: for these two groups an increase by 1% in average BMI leads, respectively, to an increase by 0:93% and 1:26% in current BMI.

Reference Type

Conference proceeding

Book Title

2018 Add Health Users Conference


Johxhe, Majlinda
Corrado, Luisa

Year Published


City of Publication

Bethesda, MD

Reference ID