Helicobacter pyloriGastritisGastritis, AtrophicGastric MucosaHelicobacter InfectionsPyloric AntrumGastritis, HypertrophicMetaplasiaStomachGastroscopyPepsinogen AStomach NeoplasmsAchlorhydriaBile RefluxStomach UlcerGastrinsPeptic UlcerChronic DiseasePepsinogen CStomach DiseasesDuodenal UlcerDyspepsiaHelicobacter felisHelicobacter heilmanniiDuodenitisAnemia, PerniciousParietal Cells, GastricBiopsyHelicobacterUreasePostgastrectomy SyndromesPepsinogensGastric JuiceEndoscopy, GastrointestinalPrecancerous ConditionsEndoscopyAtrophySymptom AssessmentAnti-Ulcer AgentsCampylobacterDepressionSeverity of Illness IndexAcinonyxGastric AcidAntigens, BacterialOmeprazoleGastroesophageal RefluxGastrointestinal DiseasesAmoxicillinH(+)-K(+)-Exchanging ATPasePrevalenceAutoimmune DiseasesDuodenogastric RefluxEndoscopy, Digestive SystemProspective StudiesGastric FundusAntibodies, BacterialQuestionnairesGastroenterostomyRisk FactorsTreatment OutcomeFollow-Up StudiesGastric Acidity DeterminationIntrinsic FactorEsophagitisBismuth