Pearson correlations were used to examine initial relationships between genotype/allele variables, dietary restraint, impulsivity, and binge eating. Hierarchical regression models using a moderated regression framework (Aiken & West, 1991) were then used to examine whether impulsivity and dietary restraint moderate relationships between candidate genes and binge eating Notably, our use of the term “moderator” does not map on to the use by Kraemer et al. (2001), but is more closely related to moderation as discussed in the gene-environment interaction literature (Moffit et al., 2005). The gene-environment literature emphasizes the diathesis-stress model, in which the “diathesis” (baseline characteristic) is the gene, and the “stress” is the environmental exposure/moderator that triggers the diathesis and leads to the outcome. Previous gene-environment interaction studies have used both moderated linear and logistic regression to examine environmental moderation of the relationship between genes and psychiatric symptoms/disorders (e.g., Laucht et al., 2007).
