APOE and Alzheimer disease: First, we synthesized the original data as a single case-controlled study and obtained an abnormal result in which the CHAT rs3810950 polymorphism played a protective role against the AD risk among non-ApoE ɛ4 carriers (OR = 0.82, P = 0.014, shown in Table 5A), which was entirely inconsistent with the results showing the destructive role of this polymorphism obtained from the meta-analysis based on the overall population [10].