SIRT1 and Alzheimer disease: A previous study by Kumar et al. (2013) described that the range level of SIRT1 measured from MCI subjects was 3.35 to 3.81 ng/μL, whereas that from AD subjects was 1.37 to 2.99 ng/μL, compared to the normal elderly group, 4.41 to 5.96 ng/μL.