Table 1.

Research questions explored by the review

Research question	Explanatory data
Is H pylori infection associated with circulating ghrelin levels?	Data comparing circulating ghrelin concentration in H pylori positive and negative subjects
What is the effect of eradicating H pylori on circulating ghrelin levels?	Data comparing the circulating ghrelin concentration before and after H pylori eradication
What is the effect of H pylori infection on ghrelin expression in the stomach?	Data assessing any of the gastric ghrelin parameters