Helicobacter pylori is usually acquired during childhood. The reports from the last two decades pointed out a decrease in H. pylori prevalence across geographical areas worldwide compared to previously reported data. Most of the studies performed in America found an overall H. pylori infection prevalence of approximately 50%. The most important risk factors in America include being male, poor adherence or difficult access to treatment, and the lack of in-home water service. Despite the descending trend in prevalence worldwide, the overall prevalence in Africa remains very high (70%). Nevertheless, the prevalence of H. pylori in children without gastrointestinal who underwent screening was reported to be only 14.2%. The main risk factors in Africa are having a traditional pit or no toilet, poverty, birth order, source of drinking water, or being a farmer. Asia seems to have the widest variations in terms of H. pylori prevalence. Several risk factors were reported in Asia to be associated with this infection, such as lower income and educational level, house crowding, rural residence, ethnicity, the use of tanks as water supplies, alcohol drinking, active smoking, eating spicy food or raw uncooked vegetables, poor living conditions and sanitation. The overall prevalence of H. pylori infection in European children is almost 25%. Portugal has the highest prevalence of all European countries at 66.2% in children 13 years of age. The risk factors in European individuals consist of living in rural areas, eating unwashed fruits and vegetables, not washing hands after school, low parental education and unemployment, and short education duration. Further studies are required to identify the precise mechanisms involved in the discrepancies of H. pylori prevalence worldwide.
Keywords: Helicobacter pylori infection; children; worldwide.