Gastritis, AtrophicGastritisPepsinogen AHelicobacter pyloriGastric MucosaHelicobacter InfectionsPepsinogen CAchlorhydriaGastroscopyStomach NeoplasmsAnemia, PerniciousMetaplasiaGastrinsPepsinogensPyloric AntrumStomachParietal Cells, GastricPrecancerous ConditionsGastric JuiceIntrinsic FactorStomach DiseasesPostgastrectomy SyndromesStomach UlcerAtrophyGastric AcidMoxibustionChronic DiseaseBiopsyPeptic UlcerGastritis, HypertrophicEndoscopy, GastrointestinalCarcinoid TumorAnti-Ulcer AgentsDuodenal UlcerEnterochromaffin-like CellsEndoscopyUreaseVitamin B 12Malabsorption SyndromesDyspepsiaOmeprazoleCorydalisGastric FundusAtractylodesSchilling TestCathepsin WAmoxicillinZollinger-Ellison SyndromeAntibodies, BacterialGastroesophageal RefluxBile RefluxJapanAutoimmune DiseasesVitamin B 12 DeficiencyColombiaGastrectomyEsophagitis, PepticAntigens, BacterialProton Pump InhibitorsRisk FactorsGastrointestinal DiseasesPrevalenceHelicobacter felisHelicobacter heilmanniiBacterial ProteinsDuodenitisChromogranin AAutoantibodies