APOE and Alzheimer disease: Though not a significant interaction (P < 0.0056 considered as significant), it is worth noting that significant positive associations of AD-tau with insoluble Aβ40 (FA: β = 12.97, p < 0.001), insoluble apoE (FA: β = 1.05, p < 0.001), and insoluble pTau181 (FA: β = 1.06, p < 0.001) were observed in AGD-tau negative cases, but not in positive cases (Additional file 1: Table S8).