| Gastric cancer is a terrible disease with high incidence and mortality worldwide.Wuwei city which located in northwest China,Gansu Province,is an area with high incidence of gastric cancer.Helicobacter pylori（H.pylori）is classified as a GroupⅠcarcinogen and plays important roles in the occurrence and progression of gastric cancer.Based on the Wuwei cohort established by a large general population,a baseline survey of H.pylori infection and main virulence factors was carried out.Part OneAnalysis of Helicobacter pylori infection and related factors based on Wuwei cohortObjectives:Based on the established large-scale general population cohort（25,000 people）in Wuwei city,a cross-sectional baseline survey was carried out to explore the H.pylori infection status and related risk factors of the local population,and the correlation between H.pylori infection and the occurrence of extragastric diseases.This study provides a theoretical basis for exploring the causes of the high incidence of gastric cancer and other upper gastrointestinal tract diseases among the local population in Wuwei city and helping to formulate prevention and control strategies.Methods:The 14C-urea breath test(14C-UBT)was used to determine the status of H.pylori infection in the established Wuwei cohort,combined with the results of gastroscopy and histopathological diagnosis of the cohort population,to analyze the infection rate of H.pylori in different gastric diseases.Questionnaires including demographic and socio-economic factors,dietary habits,lifestyles,and self-reported medical history of extragastric disease were performed.Statistical methods were used to analyze the relationship between different demographic and socio-economic,lifestyles and dietary habits risk factors and H.pylori infection,as well as the correlation between extragastric diseases and H.pylori infection.Results1.21,291 people in the cohort were finished 14C-UBT and 21,265 people were finished gastroscopy detection.Gastric mucosal biopsy was taken from 9479 people and underwent histopathological examination.The overall H.pylori infection rate in the Wuwei cohort was 52.95%（11,275/2,1291）,of which the infection rate was 52.79%for males（5290/10,021）and 53.11%for females（5985/11,270）（P=0.644）.The average age of people with H.pylori positive infection（50.10±7.47 years）was lower than that in people with non-H.pylori infection（51.04±7.85 years）（P<0.001）.2.The infection rate of H.pylori in people aged<40,40-49,50-59,and over 60years old was 56.53%,55.12%,52.56%,and 46.83%,respectively,and showing a trend of gradual decrease with age increasing（P<0.001）.The infection rate of H.pylori in people with spouses（53.19%）was significantly higher than that of non-spouses（47.99%）（P=0.002）.The infection rate of H.pylori in farmers（53.42%）was significantly higher than that in non-farmers（46.18%）（P=0.002）.H.pylori infection rate in people of illiterates（49.25%）was significantly lower than those with primary education level（51.83%）and junior or above education level（55.26%）（P<0.001）.H.pylori infection rate in people with family income of 10,000-19,999 yuan per year（55.59%）was significantly higher than those with family income of20,000-29,999 yuan per year group（52.79%）and more than 30,000 yuan per year（49.66%）（P<0.001）.There was no significant difference in H.pylori infection rate among people with different BMI.3.The infection rate of H.pylori in people who often ate quickly（51.35%）was significantly lower than that of those who ate slowly（53.39%）（P=0.014）.The infection rate of H.pylori in people who ate enough fresh vegetables and fruits more than 6 months per year（51.15%）was significantly lower than that in less than 1month（55.36%）,1-3 months（55.54%）and 4-6 months（53.62%）（P<0.001）.The infection rate of H.pylori in people with normal sleeping（53.53%）was significantly higher than that in people with mild insomnia（49.20%）,moderate insomnia（50.50%）and severe insomnia（46.67%）（P=0.001）.There was no significant difference in infection rate of H.pylori among people with smoking or non-smoking,drinking or non-drinking,eating hot food or not,eating fried food or not and different physical activities.4.Multivariate logistic regression analysis showed that when the age increased by 10 years,the risk of H.pylori infection could be decreased by 12%（OR:0.88,95%CI:0.84-0.91）.The risk of H.pylori infection could be decreased by 6%（OR:0.94,95%CI:0.91-0.96）when the family income increased to more than 30,000 yuan per year.Eating fresh vegetables and fruits for more than six months a year could decrease the risk of H.pylori infection by 6%（OR:0.94,95%CI:0.91-0.96）.People with habits of eating quickly could decrease the risk of H.pylori infection by 8%（OR:0.92,95%CI:0.86-0.98）.Meanwhile,comparing with the illiteracy,people received primary,junior high school or above education could increase the risk of H.pylori infection1.11 folds（OR:1.11,95%CI:1.07-1.16）.The risk of H.pylori infection in farmers could increase by 1.39 folds（OR:1.39,95%CI:1.24-1.57）5.There were significant difference in infection rates of H.pylori among people with different gastric diseases including non-atrophic gastritis（46.59%）,chronic atrophic gastritis（55.29%）,gastric ulcer（69.55%）,duodenal ulcer（60.76%）,compound ulcer（76.36%）,gastric polyps（53.69%）,duodenitis（55.16%）,gastric cancer（49.32%）,gastric xanthoma（72.06%）,acute gastritis（41.51%）,and submucosal lesions（47.22%）,which were diagnosed by gastroscopy（P<0.001）.Similarly,there were significant difference in infection rates of H.pylori among people with different gastric diseases diagnosed by histopathology including in non-atrophic gastritis（44.31%）,atrophic gastritis（54.28%）,intestinal metaplasia（56.58%）,low-grade intraepithelial neoplasia（58.53%）and in gastric cancer（47.74%）（P<0.001）.6.The infection rate of H.pylori in people with medical history of cholecystitis/cholecystolithiasis,hypertension and asthma was significantly lower than that in those without such history（50.13%vs 53.37%）（48.73%vs 53.67%）（47.49%vs 53.05%）（P<0.05）.There was no significant difference in H.pylori infection rate among people whether or not with a history of diabetes,hyperlipidemia,myocardial infarction,anemia and viral hepatitis（P>0.05）.Conclusion1.The infection rate of H.pylori in Wuwei cohort was 52.95%,showing a trend of decreasing with age increasing.H.pylori infection reached a peak before the age of40,which was earlier than that in areas with low incidence of gastric cancer,and this may be related to the high incidence of gastric cancer in the local area.2.Age,family income,and the months of eating enough vegetables and fruits increasing,habit of eating quickly are independent risk factors for reducing H.pylori infection among the population in Wuwei city.On the contrary,farmers and receiving primary,junior or above education increase the risk factors for H.pylori infection.3.H.pylori infection is related to occurrence of the gastric diseases in the population of Wuwei city,especially closely related to the aggravation of precancerous lesion of gastric mucosal.4.H.pylori infection was negatively correlated with the occurrence of cholecystitis/cholecystolithiasis,hypertension and asthma in Wuwei city.Part Two Study on serum antibody of virulence protein,serotype of Helicobacter pylori and correlation with gastric diseases and precancerous lesions in Wuwei cohortUrease（Ure）,cytotoxin-related gene protein（Cag A）,vacuolating cytotoxin A（Vac A）,and heat shock protein 60（Hsp60）are important virulence factors produced by Helicobacter pylori（H.pylori）.Oxygen-insensitive NADPH nitroreductase（Rdx A）is closely related to the sensitivity of H.pylori to metronidazole.The expression of the above factors is significance to the pathogenicity and drug sensitivity of H.pylori.Objectives: Based on the detection of serum antibodies of Ure,Cag A,Vac A,Hsp60 and Rdx A in people with H.pylori infected in Wuwei cohort,serotypes of H.pylori will be clarified.The relationship between serum antibodies of Ure,Cag A,Vac A,Hsp60,Rdx A and gastric precancerous lesions will be analyzed.Our work would provide theoretical basis for precision treatment of H.pylori infection and prevent gastric cancer.Methods: The sera of 1162 participants with positive 14carbon-urea breath test（14C-UBT）in the Wuwei cohort were collected.The antibodies of Ure,Cag A,Vac A,Hsp60 and Rdx A were detected by dot immunobinding assay method.The correlation between serotypes,serum antibodies Ure,Cag A,Vac A,Hsp60,Rdx A of H.pylori and demographic sociological factors,as well as different gastric diseases and gastric precancerous lesions were analyzed.The risk of serum antibodies of Cag A,vac A,Hsp60,Rdx A and different gastric diseases,pathological diagnosis were assessed.Results: 1.The positive rate of Ure,Cag A,Vac A,Hsp60 and Rdx A antibodies in 1162 participants with H.pylori infection was 100%,89.50%,85.97%,9.90% and 18.24%,respectively.Type Ⅰ H.pylori infection accounted for 90.10%,and type Ⅱ 9.90%.2.The mean age of participants with positive antibodies of Cag A,Vac A and Rdx A were lower than that of the negative participants（P < 0.05）,and the positive rates of Vac A and Rdx A antibodies in women（88.25% and 22.06%）were higher than those in men（83.59% and 13.93%）（P<0.05）.The positive rate of Rdx A antibody in non-smokers（18.66%）was higher than that in smokers（13.11%）（P<0.05）.There was no significant difference in the positive rate of other antibodies in serum among demographic and sociological factors（P > 0.05）.3.Seroprevalence of Cag A antibody and type Ⅰ H.pylori infection rates were 82.14% and 83.93% in people with gastric polyps respectively,which were significantly lower than that of chronic non-atrophic gastritis（92.05%）（P<0.05）.The risk of gastric polyps could be reduced by 48%（OR: 0.52,95% CI: 0.28 0.97）in people with Cag A antibody positive,and also could be decreased by 47%（OR: 0.43,95% CI: 0.24 0.85）in people with typeⅠ H.pylori infection.The serum antibody positive rate of H.pylori Hsp60（10.59%）was higher in people with atrophic gastritis than that of non-atrophic gastritis（6.53%）,and the risk of atrophic gastritis diagnosed by gastroscopy could be increased 1.66 folds（OR: 1.66,95%CI:1.01-2.73）in people with serum antibody positive of Hsp60.4.Seroprevalence of Cag A antibody in non-atrophic gastritis,atrophic gastritis,intestinal metaplasia,and low-grade intraepithelial neoplasia were 65.38%,86.06%,90.15% and 92.41%,respectively.People with positive Cag A antibodies could increase the risk of atrophic gastritis to 3.09 folds（OR: 3.09,95%CI: 1.22-7.82）,intestinal metaplasia to 4.70 folds（OR: 4.70,95%CI: 1.73-12.8）,and low-grade intraepithelial neoplasia to 6.50 folds（OR: 6.50,95% CI: 2.38-17.8）,comparing with non-atrophic gastritis.The infection rate of type I H.pylori in non-atrophic gastritis,atrophic gastritis,intestinal metaplasia,and low-grade intraepithelial neoplasia was 80.77%,87.27%,90.15% and 92.41%,respectively,and showing an increasing trend with aggravated lesions.The risk of atrophic gastritis,intestinal metaplasia,and low-grade intraepithelial neoplasia in people with type I H.pylori infection gradually increased,but there was no significant difference（P > 0.05）.There was no significant difference in the positive rate of other H.pylori serum antibodies among different gastric precancerous lesions（P>0.05）.Conclusions: 1.H.pylori prevalent in the population of Wuwei city is mainly higher pathogenic type Ⅰ strains,which are closely related to the atrophic gastritis,intestinal metaplasia,low-grade intraepithelial neoplasia and gastric cancer in the local area.2.People infected with Cag A positive H.pylori significantly increased the gastric precancerous lesions in Wuwei cohort.Cag A antibody positive,and type Ⅰ H.pylori infection could reduce the risk of occurrence of gastric polyps.The expression of Hsp60 of H.pylori could increase the risk of occurrence of atrophic gastritis.3.Seroprevalence of Cag A,Vac A and Rdx A in people infected with H.pylori in Wuwei population are related to age.The antibody positive rate of Rdx A is higher in women and non-smokers which indicated that H.pylori in those people may be sensitive to metronidazole than others. |
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