The Add Health study is unique because of the explicit emphasis on properly characterizing the multilevel and multidimensional aspects of adolescents’ lives as they transition to adulthood. This design in conjunction with the related and unrelated pairs data (see Harris et al., 2013) has expanded the scope of the gene-environment interaction perspective to a multilevel perspective in which environmental influences are measured at the level of the state (Boardman 2009), neighborhood (Cleveland et al., 2003; Beaver et al., 2012), and schools (Boardman et al., 2012). Most importantly, the research design enables the measurement of factors such as social norms (Boardman et al., 2008) that are otherwise difficult to assess. The assessment of these contextual factors has been highlighted as a critical area for future research in gene-environment interplay (Spittel et al., 2013) and the utilization of genome-wide data in conjunction with this social environmental backdrop may provide important insights in the etiology of complex morbidities such as obesity (Boone-Heinonen and Gordon-Larsen, 2012).
