AIM:To study possible decrease in prevalence of Helicobacter pylori(H.pylori) infection in the Czech Republic within a 10-year period.METHODS:A total of 22 centres entered the study.The catchment areas of these centres covered cities and towns with more than 20 000 inhabitants,smaller towns(≤ 20 000 inhabitants) with surrounding villages and rural areas,and were spread over the whole country,corresponding well to the geographical distribution of the Czech population.A total of 1 837 subjects(aged 5-98 years) took part in the study,randomly selected out of 38 147 people from the general population.H.pylori infection was investigated by means of a 13 C-urea breath test.Breath samples in duplicates were analysed using isotope ratio mass spectrometry.The cut-off point was 3.5.Social and demographic characteristics were based on data from self-completed questionnaires.RESULTS:The overall prevalence of H.pylori infection was 23.5%(430/1826),and 4.8%(20/420) in children aged 15 or less.There was no statistically significant difference in prevalence between males(24.3%;208/857) and females(22.9%,222/969,P = 0.494).H.pylori infection was strongly associated with higher age,among subjects aged 55+ years,prevalence of H.pylori infection was 39.8%(252/633,P < 0.001).The highest prevalence of H.pylori infection was found among persons aged 55-64 years(43.9%,97/221) and 75+ years(37.9%,58/153).Among study subjects aged 15+ years,prevalence of H.pylori infection was significantly increased in those with lowest education(odds risk 3.19,95% CI 1.87-5.47).Compared to never married(14.1%),the prevalence of H.pylori infection was statistically significantly higher among married(35.4%,246/694,P < 0.001),divorced(36.8%,49/133,P < 0.001) and widowed study subjects(40.2%,45/112,P < 0.001),both in minimally and fully adjusted analysis.There was no significant difference in the prevalence of H.pylori infection between married and widowed subjects(35.4%,246/694 vs 40.2%,45/112,P = 0.389).There was little variation in smoking prevalence across categories of smoking and there was no evidence of an increased risk ofH.pylori infection among current or past smokers in our data(odds risk 1.04 with 95% CI 0.78-1.40 for current smokers;odds ratio 0.83 with 95% CI 0.60-1.16 for former smokers).The current prevalence of H.pylori in 2011 was significantly lower compared to the prevalence reported from identical geographical areas in 2001(23.5%vs 41.7%,P < 0.001).CONCLUSION:The overall prevalence of H.pylori infection in the general population has fallen substantially in the Czech Republic over the past 10 years. AIM: To study possible decrease in prevalence of Helicobacter pylori (H.pylori) infection in the Czech Republic within a 10-year period. METHODS: A total of 22 cententues entered the study. Catchment areas of these centers covered cities and towns with more than 20 000 inhabitants, smaller towns (≤ 20 000 inhabitants) with surrounding villages and rural areas, and were spread over the whole country, corresponding well to the geographical distribution of the Czech population. A total of 1 837 subjects (aged 5- 98 years) took part in the study, randomly selected out of 38 147 people from the general population. H. pylori infection was investigated by means of a 13 C-urea breath test. Breath samples in duplicates were analyzed using isotope ratio mass spectrometry. The cut-off point was 3.5. Social and demographic characteristics were based on data from self-completed questionnaires .RESULTS: The overall prevalence of H.pylori infection was 23.5% (430/1826), and 4.8% (20/420) in children aged 15 or less.Ther e was no quite significant difference in prevalence between males (24.3%; 208/857) and females (22.9%, 222/969, P = 0.494). H. pylori infection was strongly associated with higher age, among subjects aged 55+ years , prevalence of H.pylori infection was 39.8% (252/633, P <0.001). The highest prevalence of H.pylori infection was found among persons aged 55-64 years (43.9%, 97/221) and 75+ years ( 37.9%, 58/153) .Among study subjects aged 15+ years, prevalence of H.pylori infection was significantly increased those with the lowest education (odds risk 3.19, 95% CI 1.87-5.47) .Compared to never married (14.1% ), the prevalence of H.pylori infection was statistically significantly higher among married subjects (35.4%, 246/694, P <0.001), divorced (36.8%, 49/133, P <0.001) / 112, P <0.001), both in minimally and fully adjusted analysis. Here was no significant difference in the prevalence of H. pylori infection between married and widowed subjects (35.4%, 246/694 vs 40.2%, 45/112, P = 0.389) .Th ere was little variation in smoking prevalence across categories of smoking and there was no evidence of an increased risk of H.pylori infection among current or past smokers in our data (odds risk 1.04 with 95% CI 0.78-1.40 for current smokers; odds ratio 0.83 with 95% CI 0.60-1.16 for former smokers. The current prevalence of H. pylori in 2011 was significantly lower compared to the prevalence reported from identical geographical areas in 2001 (23.5% vs 41.7%, P <0.001) .CONCLUSION: The overall prevalence of H.pylori infection in the general population has fallen substantially in the Czech Republic over the past 10 years.