APP and Alzheimer disease: AD risk was lower for the APP gene-534G/A site in the dominant model (adjusted OR = 0.693, 95% CI: 0.559–0.845, P<0.001), and there was no AD risk in the recessive model (adjusted OR = 0.576, 95% CI: 0.264–1.019, P=0.062); with the G allele as a reference, the A allele was a protective factor for AD risk (adjusted OR = 0.700, 95% CI: 0.573–0.840, P<0.001).