This paper focuses on methods for SNP × E case-control and nested case-control studies. The most common approach to investigate multiplicative GxE interactions is to incorporate a product interaction term within a logistic regression model. Some Think Tank participants noted that even when testing for departures from a multiplicative odds ratio model is the primary goal, other approaches may be more powerful than logistic regression [Hein, et al. 2008]. Other participants noted that these methods have their own drawbacks, and that logistic regression has the advantage of widespread familiarity. In this section we outline alternative approaches which merit further consideration, and touch on which may be most appropriate for use in the context of characterization, discovery, or both. The different approaches are summarized in table 1, and statistical software resources are summarized in table 2.
