BACKGROUND Helicobacter pylori(H.pylori)infection is a risk factor for gastric cancer(GC),especially in East Asian populations.Most East Asian populations infected with H.pylori are at higher risk for GC than H.pylori...BACKGROUND Helicobacter pylori(H.pylori)infection is a risk factor for gastric cancer(GC),especially in East Asian populations.Most East Asian populations infected with H.pylori are at higher risk for GC than H.pylori-positive European and United States populations.H.pylori eradication therapy reduces gastric cancer risk in patients after endoscopic and operative resection for GC,as well as in non-GC patients with atrophic gastritis.AIM To clarify the chemopreventive effects of H.pylori eradication therapy in an East Asian population with a high incidence of GC.METHODS PubMed and the Cochrane library were searched for randomized control trials(RCTs)and cohort studies published in English up to March 2019.Subgroup analyses were conducted with regard to study designs(i.e.,RCTs or cohort studies),country where the study was conducted(i.e.,Japan,China,and South Korea),and observation periods(i.e.,≤5 years and>5 years).The heterogeneity and publication bias were also measured.RESULTS For non-GC patients with atrophic gastritis and patients after resection for GC,4 and 4 RCTs and 12 and 18 cohort studies were included,respectively.In RCTs,the median incidence of GC for the untreated control groups and the treatment groups was 272.7(180.4–322.4)and 162.3(72.5–588.2)per 100000 person-years in non-GC cases with atrophic gastritis and 1790.7(406.5–2941.2)and 1126.2(678.7–1223.1)per 100000 person-years in cases of after resection for GC.Compared with non-treated H.pylori-positive controls,the eradication groups had a significantly reduced risk of GC,with a relative risk of 0.67[95%confidence interval(CI):0.47–0.96]for non-GC patients with atrophic gastritis and 0.51(0.36–0.73)for patients after resection for GC in the RCTs,and 0.39(0.30–0.51)for patients with gastritis and 0.54(0.44–0.67)for patients after resection in cohort studies.CONCLUSION In the East Asian population with a high risk of GC,H.pylori eradication effectively reduced the risk of GC,irrespective of past history of previous cancer.展开更多
The Middle East is the home of ethnic groups from three main backgrounds: Semitic (Arabs and Jews), Indo-European (Persians and Kurdish) and Turkic (Turkish and Turkmens). Its geographic location, which has been under...The Middle East is the home of ethnic groups from three main backgrounds: Semitic (Arabs and Jews), Indo-European (Persians and Kurdish) and Turkic (Turkish and Turkmens). Its geographic location, which has been under continuous influences from Asia, Europe and Africa, has made it an ideal site for epidemiological studies on Helicobacter pylori (H. pylori) infection and genotyping. The gastric cancer rate differs in this region from very high in Iran (26.1/105) to low in Israel (12.5/105) and very low in Egypt (3.4/105). Epidemiological studies showed that the prevalence of H. pylori is almost similar in those countries with a high level of infection in childhood. Importantly, the frequency of vacA s1 and m1 regions and cagA+ genotypes were higher in non Semitic populations who inhabit the North than Semitic populations, the inhabitants of Southern parts of the Middle East. H. pylori infection prevalence, distribution pattern of virulence factors, diet and smoking could not have explained the difference in cancer rate. This reflects the multifactorial aetiology of gastric cancer and suggests that H. pylori infection does not always directly correlate with the risk for gastrointestinal disease, such as gastric cancer. Further detailed investigations and international comparative studies of each risk factor needto be performed to investigate whether this represents a true enigma.展开更多
Helicobacter pylori(H.pylori)colonizes the stomach of humans and causes chronic infection.The majority of bacteria live in the mucus layer overlying the gastric epithelial cells and only a small proportion of bacteria...Helicobacter pylori(H.pylori)colonizes the stomach of humans and causes chronic infection.The majority of bacteria live in the mucus layer overlying the gastric epithelial cells and only a small proportion of bacteria are found interacting with the epithelial cells.The bacteria living in the gastric mucus may act as a reservoir of infection for the underlying cells which is essential for the development of disease.Colonization of gastric mucus is likely to be key to the establishment of chronic infection.How H.pylori manages to colonise and survive in the hostile environment of the human stomach and avoid removal by mucus flow and killing by gastric acid is the subject of this review.We also discuss how bacterial and host factors may together go some way to explaining the susceptibility to colonization and the outcome of infection in different individuals.H.pylori infection of the gastric mucosa has become a paradigm for chronic infection.Understanding of why H.pylori is such a successful pathogen may help us understand how other bacterial species colonise mucosal surfaces and cause disease.展开更多
文摘BACKGROUND Helicobacter pylori(H.pylori)infection is a risk factor for gastric cancer(GC),especially in East Asian populations.Most East Asian populations infected with H.pylori are at higher risk for GC than H.pylori-positive European and United States populations.H.pylori eradication therapy reduces gastric cancer risk in patients after endoscopic and operative resection for GC,as well as in non-GC patients with atrophic gastritis.AIM To clarify the chemopreventive effects of H.pylori eradication therapy in an East Asian population with a high incidence of GC.METHODS PubMed and the Cochrane library were searched for randomized control trials(RCTs)and cohort studies published in English up to March 2019.Subgroup analyses were conducted with regard to study designs(i.e.,RCTs or cohort studies),country where the study was conducted(i.e.,Japan,China,and South Korea),and observation periods(i.e.,≤5 years and>5 years).The heterogeneity and publication bias were also measured.RESULTS For non-GC patients with atrophic gastritis and patients after resection for GC,4 and 4 RCTs and 12 and 18 cohort studies were included,respectively.In RCTs,the median incidence of GC for the untreated control groups and the treatment groups was 272.7(180.4–322.4)and 162.3(72.5–588.2)per 100000 person-years in non-GC cases with atrophic gastritis and 1790.7(406.5–2941.2)and 1126.2(678.7–1223.1)per 100000 person-years in cases of after resection for GC.Compared with non-treated H.pylori-positive controls,the eradication groups had a significantly reduced risk of GC,with a relative risk of 0.67[95%confidence interval(CI):0.47–0.96]for non-GC patients with atrophic gastritis and 0.51(0.36–0.73)for patients after resection for GC in the RCTs,and 0.39(0.30–0.51)for patients with gastritis and 0.54(0.44–0.67)for patients after resection in cohort studies.CONCLUSION In the East Asian population with a high risk of GC,H.pylori eradication effectively reduced the risk of GC,irrespective of past history of previous cancer.
文摘The Middle East is the home of ethnic groups from three main backgrounds: Semitic (Arabs and Jews), Indo-European (Persians and Kurdish) and Turkic (Turkish and Turkmens). Its geographic location, which has been under continuous influences from Asia, Europe and Africa, has made it an ideal site for epidemiological studies on Helicobacter pylori (H. pylori) infection and genotyping. The gastric cancer rate differs in this region from very high in Iran (26.1/105) to low in Israel (12.5/105) and very low in Egypt (3.4/105). Epidemiological studies showed that the prevalence of H. pylori is almost similar in those countries with a high level of infection in childhood. Importantly, the frequency of vacA s1 and m1 regions and cagA+ genotypes were higher in non Semitic populations who inhabit the North than Semitic populations, the inhabitants of Southern parts of the Middle East. H. pylori infection prevalence, distribution pattern of virulence factors, diet and smoking could not have explained the difference in cancer rate. This reflects the multifactorial aetiology of gastric cancer and suggests that H. pylori infection does not always directly correlate with the risk for gastrointestinal disease, such as gastric cancer. Further detailed investigations and international comparative studies of each risk factor needto be performed to investigate whether this represents a true enigma.
基金Supported by A post graduate student grant awarded by Irish Research Council for Science Engineering and Technology(To Dunne C)an award from the Health Research Board Ireland(To Dolan B)a grant from Science Foundation Ireland,No.08/SRC/B1393
文摘Helicobacter pylori(H.pylori)colonizes the stomach of humans and causes chronic infection.The majority of bacteria live in the mucus layer overlying the gastric epithelial cells and only a small proportion of bacteria are found interacting with the epithelial cells.The bacteria living in the gastric mucus may act as a reservoir of infection for the underlying cells which is essential for the development of disease.Colonization of gastric mucus is likely to be key to the establishment of chronic infection.How H.pylori manages to colonise and survive in the hostile environment of the human stomach and avoid removal by mucus flow and killing by gastric acid is the subject of this review.We also discuss how bacterial and host factors may together go some way to explaining the susceptibility to colonization and the outcome of infection in different individuals.H.pylori infection of the gastric mucosa has become a paradigm for chronic infection.Understanding of why H.pylori is such a successful pathogen may help us understand how other bacterial species colonise mucosal surfaces and cause disease.
