Among the 10 cathepsins, IVW analysis suggested that cathepsin H increased the risk of developing AD (odds ratio [OR] = 1.040; 95% CI = 1.011–1.069; p = 0.005), which is consistent with the WM method (OR = 1.050; 95% CI = 1.026–1.075; p < 0.001) and the MR Egger (OR = 1.060; 95% CI = 1.022–1.100; p = 0.012) method. This evidence concerns the gene CTSS and Alzheimer disease.