For further analysis, they compared the gut microflora diversity of H. pylori-infected patients with gastric cancer or gastric ulcer (CA/GU-Hp+) with relatively milder gastric diseases like non-ulcer dyspepsia or gastritis with and without H. pylori infection (NUD/GAS-Hp+ and NUD/GAS-Hp-) and gastroesophageal reflux disease without H. pylori infection (GERD-Hp-). Here, HP is linked to gastroesophageal reflux disease.