In moving towards a personalized, or stratified, medicine paradigm, it will be important to develop well-calibrated models for the joint effects of all known SNPs and environmental factors. To this end, one might select models based on overall goodness-of-fit tests [Hosmer, et al. 1997], rather than on the significance of individual interaction terms. Think Tank participants discussed how it might be appropriate to build models that assess the interaction between environmental exposures and genetic susceptibility through categories of polygenic risk-scores [Garcia-Closas, et al. 2013]. Participants recognized that such models have limited biological interpretation due to mixing of SNPs with different biological functions. However, they may adequately capture variation in joint risk.
