Because four included studies in this meta-analysis provided the genotype data of CHAT rs3810950 polymorphism and ApoE-ε4 allele [10, 12, 14, 15], we further operated a risk-stratification analysis to calculate the association of rs3810950 polymorphism with AD based on the absence and presence of ApoE-ε4. The gene discussed is APOE; the disease is Alzheimer disease.