PPARA and Alzheimer disease: The results of the KEGG enrichment analysis demonstrated that the DEPs of the DM group were mainly involved in Alzheimer’s disease, pathways of neurodegenerative diseases, GABAergic synapses, the PPAR signaling pathway, the Ras signaling pathway, oxidative phosphorylation, fatty acid degradation, protein processing in the endoplasmic reticulum, valine, leucine, and isoleucine degradation, pyruvate metabolism, biosynthesis of unsaturated fatty acids, necroptosis, and ferroptosis.