test that do not show strong evidence for multiplicative interaction when a standard GxE interaction test is performed [Hancock, et al. 2012; Manning, et al. 2012]. In one case the joint test allowed for identification of novel genetic loci not because of underlying GxE interactions, but because of precision gained by including a known risk-factor in a linear regression model [Manning, et al. 2012]; however, such a gain in power may not be realized with logistic regression [Mefford and Witte 2012].
