SIRT1 is an important protective gene against hippocampal atrophy and its induced cognitive impairment during aging.794 Surgery-induced downregulation of hippocampal SIRT1 participates in cognitive impairment after surgery by inhibiting the autophagy process and activating apoptosis.795 Additionally, exposure to fluoride could lead to cognitive impairment, and the underlying mechanisms might be related to oxidative stress and mitochondrial dysfunction. This evidence concerns the gene SIRT1 and hippocampal atrophy.