[Epidemiology of Helicobacter pylori infection]

About 50% of adults in the developed and 80-90% in the developing countries are estimated to be infected by Helicobacter pylori. Being 68% nationally, this rate is higher in the northern continental parts of Croatia, which also have higher gastric cancer rates. Low socio-economic status, poor living conditions in childhood (the age when Helicobacter pylori is typically acquired), and exposure to the stomach content of an infected person are risk factors for Helicobacter pylori. Most of the infected are symptomless, with 10 to 20% subsequently developing the disease, and this mainly from peptic ulcer, asymptomatic chronic gastritis and chronic dyspepsia. Less than 5/10,000 become affected with adenocarcinoma, MALT lymphoma or primary non-Hodgkin's gastric lymphoma. Helicobacter pylori is under intensive study for possible association with other diseases. As transmission route of the infection is still unclear, any mechanism allowing the bacteria entry into a non-infected individual's stomach is probably a possibility. In addition to improved socio-economic status, eradication or vaccination may be contributors to the reduction in the number of the infected.