Although a replicable joint effect does not require a significant logistic regression interaction term, it appears that if the proportional increase in explained variance is great enough (e.g. over 80%), logistic regression can detect a significant interaction term. The first SNP pair in Table 2, rs16969968 and rs2133965, with nearly 90% increase in explained variance, was the only pair from this table for which the logistic regression interaction term was associated with a p value <0.05. In contrast, all five pairs from Table 4, which focused on large proportional increases in explained variance, had interaction p values <0.05.
