APOE and post-traumatic stress disorder: Rather, and contrary to our hypothesis that PTSD would be associated with elevated levels of ATN biomarkers, the SEM revealed a negative correlation between PTSD and Factor TN that fell just short of our multiple testing threshold (β = − 0.140, p = 0.003) controlling for age, sex, number of lifetime traumas, APOE ε4, the APOE ε4 x PTSD interaction term, the ancestry PCs, a DNAm-based smoking score, and effects of the four EWAS-significant probes.