PREVALENCE OF H.PYLORI: The prevalence of H. pylori varies throughout the world In developing world, 80% of the population are infected by the age of 20. In the United States this organism is rare in childhood. The overall prevalence of H. pylori in the United States is 30% The rate of infection with H. pylori in industrialized countries has decreased in recent decades. ALSO NOTE: Two factors that predispose to higher colonization rates inare Poor socioeconomic status Less education. Other risk factors for H. pylori infection are (1) Bih or residence in a developing country (2) Domestic crowding (3) Unsanitary living conditions (4) Unclean food or water (5) Exposure to gastric contents of an infected individual. Ref: Harrison-E-18,P-2442.