Despite known large effects of environmental exposures on complex disease risk, there have been limited efforts to incorporate these factors into large-scale genetic studies. Appropriate modeling of the environment is especially critical when a phenotype or trait of interest is influenced by gene-by-environment interactions (GxE). That is, genetic risk factors not only alter average risk but also influence sensitivity to the effects of environmental adversities. However, the majority of GxE studies have been underpowered and conducted using samples of primarily European descent, which limits the assessment of GxE and thereby the identification of modifiable targets for intervention and prevention among understudied groups (Duncan et al., 2014). We note that the statistical definition of GxE depends on the choice of modelling on an additive or multiplicative scale (Kendler and Gardner, 2010). Greater representation of diverse individuals is critically needed in order to increase our understanding of how the interrelated contributions of genes and environment vary across social and cultural groups, and how these factors may interact.
