S100A8 and Parkinson disease: Finally, the causal relationship between HP CagA antibody level and the tremor/PIGD score ratio using the IVW method, HP OMP antibody level and the tremor/PIGD score ratio using the MR Egger method, HP VacA antibody level and dementia due to PD using the MR Egger method, and HP OMP antibody level and drug-induced secondary parkinsonism using the IVW method, all yielded consistent results under both IVs selection thresholds, as shown in Figure 2.