In Industrialized Nations
In Western countries, research suggests that there is a decline in gastritis cases caused by H. pylori infection. However, these H. pylori cases appear to have been replaced by autoimmune gastritis.
In Developing Nations
Conversely, in developing countries, chronic gastritis is a relatively common disease. There, it affects roughly 50-80% of the population, depending on region and socioeconomic status. This fact reflects the impact that hygiene has on the transmission of H. pylori, and subsequent development of gastritis symptoms.