The Prevalence, Risk Factors and Optimal Biopsy Protocol of BE

To do one biopsy at the proximal part of the longest columnar-lined esophagus.

To do three biopsy at the proximal, middle and distal part of the longest columnar-lined esophagus.

To do 4-quadrant biopsy every 1-2 cm at the esophagogastric junction. Seattle protocol has been considered as the gold standard biopsy protocol for patients with suspected Barrett's Esophagus.

The participants will receive meticulous endoscopic examination with narrow-band imaging.