A Prospective Cohort Study on Endoscopic Features of Upper Gastrointestinal Tract at High Altitude (Zaduo County)

To prospectively enroll participants undergoing gastroscopy at Zaduo County People's Hospital and perform paired analyses with matched cases from Jilin Province. This aims to characterize the endoscopic features of esophageal diseases specific to the high-altitude population in Zaduo County.

Inclusion Criteria: * Aged ≥18 years; * Resided in Zaduo County for ≥6 months; * Undergoing painless (sedated) gastroscopy at our institution; * Absence of severe cardiopulmonary diseases or other conditions contraindicating gastroscopy; * Voluntary provision of written informed consent. Exclusion Criteria: * Emergency endoscopy; * History of partial or total esophagogastrectomy; * Planned endoscopic ultrasound (EUS) or endoscopic submucosal dissection (ESD); * Comorbidities including severe cardiac, hepatic, or renal dysfunction, or malignant tumors; * Pregnancy or lactation, chronic alcoholism, or psychiatric disorders precluding cooperation; * Participation in other interventional clinical trials within the recent past; * Age \