What percentage of the world's population is infected with Helicobacter pylori (H. pylori)?

Global Prevalence of Helicobacter pylori Infection

Approximately half (50%) of the world's population is infected with Helicobacter pylori, with significant geographic variation ranging from less than 20% in some developed countries to over 80% in parts of Africa and developing nations. 1

Geographic Distribution and Variation

• The highest prevalence of H. pylori infection is found in Africa, with a pooled prevalence of 70.1%, while Oceania has the lowest prevalence at 24.4% 2

• Country-specific prevalence rates vary dramatically, from as low as 18.9% in Switzerland to 87.7% in Nigeria 2

• In developing countries, 70-90% of the population carries H. pylori, while developed nations have significantly lower rates 3

• The prevalence is declining in developed countries due to improvements in sanitation, standards of living, and housing, especially provisions for indoor plumbing and clean water 1

Risk Factors and Transmission

• H. pylori infection is generally acquired in childhood, especially via transmission within families 1

• Humans are the principal reservoir for H. pylori, with limited evidence for significant animal reservoirs 4

• Transmission can occur through several routes:

  • Person-to-person transmission (oral-oral or fecal-oral routes) 4
  • Waterborne transmission, particularly in areas with untreated water 4
  • Iatrogenic transmission following endoscopy (proven mode) 4

• Risk factors for infection include:

  • Low socioeconomic status 4
  • Crowded or high-density living conditions 4
  • Inadequate sanitation practices 4
  • Poor hygiene 4

Clinical Significance and Health Impact

• H. pylori is a World Health Organization (WHO)-designated carcinogen and the strongest known risk factor for noncardia gastric adenocarcinoma 1

• The infection is causally linked to peptic ulcer disease and accounts for 15% of the total cancer burden globally 1

• Up to 89% of all gastric cancer is attributable to H. pylori infection 1

• Among those infected with H. pylori, the lifetime risk of developing peptic ulcer is approximately 17% (1 in 6) 1

• The lifetime risk of developing gastric cancer varies geographically from approximately 0.6% in the United States to 20% in high-risk countries like Japan and China 1

Implications for Testing and Treatment

• All major gastroenterological societies recommend that H. pylori be eradicated in individuals who test positive 1

• Countries with high gastric cancer incidence (such as Japan, Korea, Taiwan, and China) have begun implementing population-wide H. pylori screening and treatment programs 1

• In the United States, targeted testing is recommended for high-risk subpopulations including Native Americans, Black Americans, Hispanics, and immigrants from high-risk countries 1

• Increasing antibiotic resistance has resulted in declining treatment success rates, necessitating careful selection of eradication regimens 5, 6

• Eradication of H. pylori infection has been shown to reduce peptic ulcer recurrence, premalignant gastric lesions, gastric cancer incidence, and gastric cancer-related deaths 1

Pitfalls and Caveats

• The prevalence of H. pylori varies significantly within countries based on socioeconomic factors, with disadvantaged subpopulations maintaining higher infection rates even in developed nations 1

• Immigrants from high-prevalence regions maintain their risk of H. pylori-related diseases similar to their country of origin, increasing the healthcare burden in host countries 1

• Antibiotic resistance has reached alarming levels worldwide, affecting treatment efficacy and requiring region-specific approaches to eradication 5

• Despite declining prevalence in developed nations, H. pylori remains a significant global health concern due to its role in gastric cancer development and other gastrointestinal diseases 1, 2