The current study added specific examination of the following central questions (Supplementary Fig. 1): (i) are peripheral metabolic sex differences changed owing to presence of (probable) AD?, (ii) are metabolite associations with A-T-N biomarkers modified by sex?, and (iii) is there evidence for APOE ε4 status influencing metabolite associations with A-T-N biomarkers that show differences between sexes? This evidence concerns the gene APOE and Alzheimer disease.