• acquired condition as a response to gastro-oesophageal reflux which leads to a columnar lined distal oesophagus
• risk increased: male, age, obesity, smoking, alcohol and frequency of reflux episodes
• known association with transformation to adenocarcinoma
• pain is generally a feature of GORD rather than Barrett's

Definition from British Soc of Gastroenterologists: Barrett’s oesophagus is defined as an oesophagus in which any portion of the normal distal squamous epithelial lining has been replaced by metaplastic columnar epithelium, which is clearly visible endoscopically (≥1 cm) above the GOJ and confirmed histo-pathologically from oesophageal biopsies

References include
Brit Soc GI - barrett's