A population based study of Helicobacter pylori infection in a European country: the San Marino Study. Relations with gastrointestinal diseases.

Helicobacter pylori is present worldwide but few large population studies exist on the epidemiology of the infection. A random cross sectional study was performed of H pylori infection in the adult population of San Marino, a European country with high gastric cancer rate, to assess its prevalence and to evaluate its relations with gastrointestinal disease. In 2237 subjects (77% of the initial sample) H pylori IgG antibodies were detected with enzyme linked immunosorbent assay (ELISA) and immunoblotting. A questionnaire including questions about occupation, place of birth, and smoking was given to all subjects. Dyspepsia, peptic ulcer, and gastric cancer in the subjects, relatives, and partners as well as use of drug, dental treatment/prostheses, and gastrointestinal endoscopies, were evaluated by multivariate analysis. H pylori prevalence was of 51%, increased with age from 23% (20-29 years) to 68% (> or = 70 years), and was higher among manual workers. H pylori was independently associated with ulcer (OR = 1.63, 95% confidence intervals (CI) = 1.16 to 2.27), H2 antagonists (OR = 1.94, 95% CI = 1.21 to 3.10), and benzodiazepines (OR = 1.57, 95% CI = 1.02 to 2.42), dental prostheses (OR = 1.25, 95% CI = 1.05 to 1.49), gastroscopy in the past five years (OR = 1.50, 95% CI = 1.05 to 2.14), peptic ulcer in siblings (OR = 1.52, 95% CI = 1.09 to 2.12), gastric cancer in father (OR = 1.61, 95% CI = 1.02 to 2.52). The association of seropositivity with history of ulcer, gastric cancer in family, gastroscopy, and H2 antagonists suggests that H pylori is an epidemiological key factor in the pathogenesis of gastroduodenal diseases in this area.     

Helicobacter pylori infection in 1st degree relatives of Chinese gastric cancer patients

OBJECTIVE: Familial aggregation of gastric cancer has been linked to familial clustering of Helicobacter pylori infection. Patterns and risk factors associated with H. pylori infection were investigated in 1st degree relatives of Chinese gastric cancer patients. MATERIAL AND METHODS: Gastric cancer relatives were invited for screening endoscopy. H. pylori infection was diagnosed by endoscopic and serological methods. RESULTS: Among the 270 cancer relatives examined, 161 (59.6%) were found to be infected with H. pylori. The prevalence of infection in cancer relatives was significantly higher than age- and gender-matched dyspeptic control (45.5%, p=0.0006). The mean age of H. pylori-infected relatives was significantly older than that of non-infected relatives (43.9 versus 38.3 years; p<0.001). The prevalence of H. pylori infection was higher in those with more siblings (p=0.013, chi(2) test for trend). Moreover, individuals whose siblings had stomach cancer were more likely to have H. pylori infection than those with a parental history of cancer (68.2% versus 51.8%, p=0.007). In contrast, the youngest sibling had a significantly lower H. pylori infection rate than other siblings (39.2% versus 64.2%, p=0.001). Using multiple logistic regression, it was found that age >45 years (OR=1.8; 95% CI, 1.02-3.3) and a history of gastric cancer in siblings (OR=1.9; 95% CI, 1.06-3.3) were independent risk factors for H. pylori infection, and that the youngest sibling in the family had a reduced risk (OR=0.45; 95% CI, 0.24-0.84). CONCLUSIONS: This study identifies the patterns and risk factors for H. pylori in gastric cancer relatives, which may shed light on the evolving epidemiology of H. pylori infection in Chinese patients.     

Association of Helicobacter pylori infection with atrophic gastritis and intestinal metaplasia

AIMS: To evaluate the effect of Helicobacter pylori infection and aging on atrophy and intestinal metaplasia of the gastric mucosa. METHODS: One hundred and sixty-three patients were divided into three age groups and underwent an upper gastrointestinal endoscopy where no esophagitis, peptic ulcers, or malignancies were detected. Two biopsy specimens were obtained from the anterior and posterior walls of the antrum and of the fundus. These were used to evaluate the grade of gastritis, bacterial culture and histologic evidence of H. pylori infection. RESULTS: Helicobacter pylori infection was found to be directly associated with an increased risk of gastritis grade (odds ratio (OR) = 90 (95% CI; 30-270)). An age of 60 years and older along with H. pylori infection was also strongly associated with an increased risk of atrophy (OR = 6.6, (95% CI; 2.9-15.2)); OR = 9.8, (95% CI; 2.7-35.4)), as was intestinal metaplasia of the gastric mucosa (OR = 5.5, (95% CI; 1.7-17.6)); OR = 7.9, (95% CI; 2.8-46.1)). The prevalence of atrophic gastritis increased with advancing age in H. pylori-infected patients, but no such phenomenon was observed in H. pylori-uninfected patients. The prevalence of intestinal metaplasia significantly increased with advancing age, irrespective of the presence of H. pylori infection. In addition, H. pylori uninfected female patients had a decreased risk of intestinal metaplasia. CONCLUSIONS: These results suggest that atrophic gastritis is not a normal aging process, but instead is likely to be the result of H. pylori infection, while intestinal metaplasia is caused by both the aging process and H. pylori infection. A decreased risk of intestinal metaplasia found in uninfected female subjects may partly explain the lower prevalence of gastric cancer in females than in males.     

A functional polymorphism of toll-like receptor 4 gene increases risk of gastric carcinoma and its precursors

BACKGROUND AND AIMS: TLR4 is a cell-surface signaling receptor involved in the recognition and host response to Helicobacter pylori. The TLR4+896A>G polymorphism linked with impaired reactivity to bacterial lipopolysaccharide may play a role in gastric carcinogenesis. METHODS: We assessed associations with premalignant gastric changes in 149 relatives of gastric cancer patients, including 45 with hypochlorhydria and gastric atrophy. We also genotyped 2 independent Caucasian population-based case-control studies of upper gastrointestinal tract cancer, initially in 312 noncardia gastric carcinoma cases and 419 controls and then in 184 noncardia gastric carcinomas, 123 cardia carcinomas, 159 esophageal cancers, and 211 frequency-matched controls. Odds ratios were computed from logistic models and adjusted for potential confounding factors. RESULTS: TLR4+896G carriers had an 11-fold (95% confidence interval [CI], 2.5-48) increased odds ratio (OR) for hypochlorhydria; the polymorphism was unassociated with gastric acid output in the absence of H pylori infection. Carriers also had significantly more severe gastric atrophy and inflammation. Seventeen percent of gastric carcinoma patients in the initial study and 15% of the noncardia gastric carcinoma patients in the replication study had 1 or 2 TLR4 variant alleles vs 8% of both control populations (combined OR = 2.3; 95% CI = 1.6-3.4). In contrast, prevalence of TLR4+896G was not significantly increased in esophageal squamous cell (2%, OR = 0.2) or adenocarcinoma (9%, OR = 1.4) or gastric cardia carcinoma (11%, OR = 1.4). CONCLUSIONS: Our data suggest that the TLR4+896A>G polymorphism is a risk factor for noncardia gastric carcinoma and its precursors. The findings underscore the role of the host innate immune response in outcome of H pylori infection.     

Two distinct aetiologies of cardia cancer; evidence from premorbid serological markers of gastric atrophy and Helicobacter pylori status

BACKGROUND: Non-cardia gastric adenocarcinoma is positively associated with Helicobacter pylori infection and atrophic gastritis. The role of H pylori infection and atrophic gastritis in cardia cancer is unclear. AIM: To compare cardia versus non-cardia cancer with respect to the premorbid state of the stomach. METHODS: Nested case-control study. To each of 129 non-cardia and 44 cardia cancers, three controls were matched. Serum collected a median of 11.9 years before the diagnosis of cancer was tested for anti-H pylori antibodies, pepsinogen I:II and gastrin. RESULTS: Non-cardia cancer was positively associated with H pylori (OR 4.75, 95% CI 2.56 to 8.81) and gastric atrophy (pepsinogen I:II <2.5; OR 4.47, 95% CI 2.71 to 7.37). The diffuse and intestinal histological subtypes of non-cardia cancer were of similar proportions and both showed a positive association with H pylori and atrophy. Cardia cancer was negatively associated with H pylori (OR 0.27, 95% CI 0.12 to 0.59), but H pylori-positive cardia cancer showed an association with gastric atrophy (OR 3.33, 95% CI 1.06 to 10.5). The predominant histological subtype of cardia cancer was intestinal and was not associated with gastric atrophy compared with the diffuse subtype ((OR 0.72, 95% CI 0.19 to 2.79) vs (OR 3.46, 95% CI 0.32 to 37.5)). Cardia cancer in patients with atrophy had an intestinal: diffuse ratio (1:1) similar to non-cardia cancer (1.9:1), whereas cardia cancers in patients without atrophy were predominantly intestinal (7:1). CONCLUSION: These findings indicate two aetiologies of cardia cancer, one associated with H pylori atrophic gastritis, resembling non-cardia cancer, and the other associated with non-atrophic gastric mucosa, resembling oesophageal adenocarcinoma. Serological markers of gastric atrophy may provide the key to determining gastric versus oesophageal origin of cardia cancer.     

Association of Helicobacter pylori infection with gastric carcinoma: a meta-analysis

OBJECTIVE: As conflicting studies have recently been published, we aimed to determine if Helicobacter pylori (H. pylori) infection is associated with gastric adenocarcinoma. METHODS: This was a meta-analysis of observational epidemiological studies. RESULTS: A total of 42 studies met the selection criteria and were categorized by the type of study design: eight cohort and 34 case-control studies. The pooled odds ratio for H. pylori in relation to gastric carcinoma was 2.04 (95% CI: 1.69-2.45). Both patient age (OR 0.77, 95% CI: 0.68-0.89) and intestinal type cancers (OR 1.14, 95% CI: 1.05-1.25) were independent effect modifiers. Analysis of other effect modifiers showed no relationship with female gender (OR 0.76, 95% CI: 0.64-0.89), stage of cancer (advanced %) (OR 1.12, 95% CI: 0.88-1.43), anatomical location (cardia %) (OR 1.54, 95% CI: 0.32-7.39) or cohort (nested case-control) studies (OR 1.72, 95% CI: 0.32-9.17). There was significant heterogeneity among the studies (tau2 = 149; p < 0.001). The quality of the studies varied considerably, with the majority of excellent studies producing positive results and the very poor to moderate studies producing mixed results. CONCLUSIONS: H. pylori infection is associated with a 2-fold increased risk of developing gastric adenocarcinoma.     

Helicobacter pylori infection and low serum pepsinogen I level as risk factors for gastric carcinoma

AIM: To study whether examination of CagA antibodies could increase the odds ratio for gastric cancer in a casecontrol study, and how often other serum markers of gastric cancer risk could be found in Helicobacter pylori-negative patients. METHODS: H pylori CagA and parietal cell antibodies (PCAs), and serum pepsinogen I (SPGI) levels were compared between patients with gastric cancer and controls who received endoscopic examination due to reasons other than gastrointestinal malignancy. RESULTS: The odds ratio (OR) for gastric cancer was 2.9 (95% CI 1.4-5.8) in H pylori + patients, and 2.4 (95% CI 1.2-4.9) in CagA+ patients. When results of H pylori and CagA antibodies were combined, OR increased to 5.0 (95% CI 2.5-10.0). Furthermore, if cardia cancer patients were excluded, the OR increased to 6.8 (95% CI 3.1-14.8). Among patients with a low SPGI level, the OR was 12.0 (95% CI 4.1-35.3). However, the risk was significant only in the older age group. The number of patients with low SPGI was significantly higher in H pylori -/CagA+ patients as compared to other cancer patients. CONCLUSION: Examination of both H pylori and CagA antibodies increases the OR for gastric cancer in our casecontrol study. CagA antibodies are important in detecting previous H pylori infection in advanced atrophic gastritis or cancer when spontaneous decline of H pylori antibodies occurs. SPGI may be helpful in screening elderly gastric cancer patients.     

Relationship between Helicobacter pylori CagA status and colorectal cancer

OBJECTIVES: Infection with Helicobacter pylori, particularly with strains positive for CagA protein, increases the risk of gastric adenocarcinoma. Few studies have explored the possible association between H. pylori infection and colorectal cancer. This study evaluated whether the seroprevalence of CagA in H. pylori-infected patients affected risk for colorectal cancer independently of H. pylori status. METHODS: In this study, we tested serum IgG antibodies against H. pylori (ELISA) and CagA protein (Western blot assay) in 67 patients with colorectal adenocarcinoma, 36 with gastric adenocarcinoma, 47 with other malignancies (cancer controls), and 45 hospitalized for transesophageal echocardiography (TEE controls). Colonic cancer and gastric cancer patients with H. pylori infection were compared to each control group and to the pooled controls using simple and adjusted analyses. RESULTS: H. pylori infection was noted in 50 colon cancer patients, 31 gastric cancer patients, 31 cancer controls, and 32 TEE controls. In all, 41 (82%), 29 (94%), 11 (35%), and 13 (41%), respectively, of these H. pylori-positive sera expressed CagA reactivity (p < 0.001 for all pairwise comparisons between cases and controls). In the adjusted analysis, infection with H. pylori CagA+ compared to H. pylori CagA- was associated with increased risk for colorectal adenocarcinoma (odds ratio = 10.6; 95% CI = 2.7-41.3; p = 0.001) and gastric adenocarcinoma (odds ratio = 88.1; 95% CI = 6.3-1229.2; p = 0.001). CONCLUSIONS: Among patients infected with H. pylori, CagA+ seropositivity is associated with increased risk for both gastric and colonic cancer. This finding should stimulate additional research into the role of cagA+ H. pylori infection in the development of colorectal cancer.     

Tobacco smoking increases the risk for gastric adenocarcinoma among Helicobacter pylori-infected individuals

BACKGROUND: The importance of tobacco smoking and Helicobacter pylori infection as risk factors in the development of gastric carcinoma was investigated through multivariate conditional logistic regression analysis in a nested case-control study. METHODS: Blood samples and a questionnaire on smoking habits were collected from a cohort of 32,906 city residents during a health screening programme from 1974 to 1992. Fifty-six cases of gastric cancer and 224 matched controls were selected. The mean interval between screening and cancer diagnosis was 5.7 years. H. pylori infection was determined by IgG-serology. Occupation categorized into blue-collar workers, white-collar workers, self-employed and unknown occupation was included in the statistical analysis as an indicator of socio-economic status. RESULTS: The proportion of current smokers was 61% among gastric cancer cases, versus 41% among controls. H. pylori seropositivity was present in 82% of the cases and 49% of the controls. In a multivariate model current smokers had an odds ratio (OR) of 2.2 (95% confidence interval (CI): 1.2-4.2). With different levels of tobacco consumption, smoking less than 20 g tobacco each day gave the OR of 2.1 (95% CI: 0.98-4.4), and the OR when smoking more than 20 g tobacco per day was 2.5 (95% CI: 1.1-5.6). The OR of H. pylori infection was 5.0 (95% CI: 2.2-11.2). Among H. pylori-seropositive citizens, current smoking was associated with an increased risk of 2.3 (95% CI: 1.1-4.7) compared with non-smoking H. pylori-positive persons. CONCLUSIONS: Tobacco smoking and H. pylori are both risk factors in the development of gastric cancer, and tobacco smoking is still a risk factor among H. pylori-infected individuals. The risk of gastric cancer among H. pylori-infected current smokers is 11 times that of non-infected individuals not currently smoking.     

Association between interleukin-1 gene polymorphisms and Helicobacter pylori infection in gastric carcinogenesis in a Chinese population

BACKGROUND AND AIM: Helicobacter pylori is a major cause of chronic gastritis and peptic ulcer disease and a definite carcinogen for gastric adenocarcinoma. However, the underlying pathogenic mechanisms are not fully understood. Interleukin-1 (IL-1) is a key cytokine involved in H. pylori-induced gastric inflammation. The present study aimed to determine polymorphisms of IL-1B and IL-1 receptor antagonist (IL-1RN) genes and their association with H. pylori infection and gastroduodenal diseases in Chinese patients. METHODS: Three hundred and ninety-nine patients with gastroduodenal diseases (129 chronic gastritis, 127 duodenal ulcer and 143 non-cardiac gastric cancer) and 264 healthy controls were genotyped for IL-1B-511 and IL-1RN gene polymorphisms by the PCR-RFLP method. H. pylori infection status was determined by a validated serological test. RESULTS: The frequency of IL-1B-511 T allele was significantly higher in H. pylori positive patients with non-cardiac gastric cancer than in both H. pylori negative patients with non-cardiac gastric cancer (60%vs 46%, P = 0.0342, OR = 1.666, 95% confidence interval [CI]: 1.045-2.656) and in healthy controls (60%vs 48%, P = 0.0071, OR = 1.665, 95%CI: 1.149-2.412). However, the polymorphism was not associated with chronic gastritis and duodenal ulcer. Multivariate logistic regression analyses identified that IL-1B-511 T/T carrier status was an independent risk factor for non-cardiac gastric cancer in the presence of H. pylori infection (adjusted OR = 3.01, 95%CI: 1.27-7.11, P = 0.01), and the frequency of IL-1B-511 T allele was an increased risk factor for developing gastric cancer (P = 0.03, adjusted OR = 2.29, 95%CI: 1.08-4.86). There was no association between IL-1RN gene polymorphisms and H. pylori infection and other gastroduodenal diseases. CONCLUSION: IL-1B-511 T allele is associated with H. pylori infection in non-cardiac gastric cancer in a Chinese population. The IL-1B-511 gene polymorphism appears to play an important role in gastric carcinogenesis in Chinese patients with H. pylori infection.     

Risk for gastric cancer in people with CagA positive or CagA negative Helicobacter pylori infection.

BACKGROUND AND AIMS: It is not known why some people with Helicobacter pylori infection develop gastric cancer whereas others do not. Whether the CagA phenotype of H pylori infection affected risk for cancer independently of other posited risk factors was evaluated. SUBJECTS: 242 persons who participated in a previous nested case-control study of gastric cancer. 179 (90 cases and 89 controls) were infected with H pylori as determined by enzyme linked immunosorbent assay (ELISA) in serum and 63 (13 cases and 50 controls) were uninfected. METHODS: Serum samples from cases and controls, obtained a mean of 14.2 years before diagnosis of cancer in the cases, were tested by ELISA for IgG antibodies against the CagA gene product of H pylori. They had previously been tested for pepsinogen I. Using logistic regression analysis, risk for cancer was compared among infected persons with CagA antibodies, infected persons without CagA antibodies, and uninfected persons. RESULTS: Subjects infected with H pylori who had CagA antibodies were 5.8-fold more likely than uninfected subjects to develop gastric cancer (95% confidence interval (95% CI) = 2.6-13.0). This was true for both intestinal (odds ratio (OR) 5.1, 95% CI = 2.1-12.2) and diffuse type (OR 10.1, 95% CI = 2.2-47.4) cancers. By contrast, H pylori infected subjects without CagA antibodies were only slightly, and not significantly, at increased risk for cancer (OR 2.2, 95% CI = 0.9-5.4) and any possible association was restricted to diffuse type carcinoma (OR 9.0, 95% CI = 1.2-65.8). Pepsinogen 1 < 50 ng/ml significantly increased risk for both cancer types in H pylori infected persons and lessened the magnitude of association between CagA and cancer. Educational attainment, cigarette smoking, and ABO blood group were not associated with malignancy. CONCLUSIONS: When compared with uninfected subjects, persons infected with CagA positive H pylori are at considerably increased risk of gastric cancer. CagA negative H pylori are less strongly linked to malignancy and may only be associated with diffuse type disease.     

Helicobacter pylori Infection and Gastric Neoplasia: Correlations With Histological Gastritis and Tumor Histology

Objective: Several authors have reported an association between Helicobacter pylori ( H. pylori ) and gastric carcinoma, but the data are conflicting. Atrophic gastritis and intestinal metaplasia (IM) have also been linked to gastric carcinoma, especially the intestinal tumor type. We investigated the relationship between H. pylori infection, gastric neoplasms, and histological gastritis.
Methods: A total of 105 patients with gastric carcinoma, 36 patients with gastric adenoma, and 105 age- and sex-matched control subjects were examined for H. pylori infection and histological gastritis. H. pylori status was evaluated by Giemsa staining and IgG serology. Mucosal inflammation, atrophy, and IM were evaluated in biopsy specimens from antrum and corpus.
Results: H. pylori seroprevalence was higher in patients with gastric carcinoma (98 of 105, 93%) and adenoma (34 of 36, 94%) than in control subjects (82 of 105, 71%,   p < 0.05  ). H. pylori was more prevalent in patients with noncardia (OR, 5.67; 95% CI, 2.25–14.44) than cardia (OR, 5.20; 95% CI, 0.65–41.68) tumors. Histologic types and tumor stage (early; OR, 6.60; 95% CI, 2.23–19.69, advanced; OR, 4.27; 95% CI, 1.21–15.03) showed no difference in H. pylori prevalence. Atrophy and IM scores were higher in patients with the intestinal- but not diffuse-type of carcinoma and adenoma than in H. pylori -positive control subjects. Smoking was associated with gastric carcinoma (OR, 3.05; 95% CI, 1.58–5.93) but not alcohol or coffee use, blood group A, or a family history of gastric cancer.
Conclusions: Our results confirm a strong association between H. pylori and gastric carcinoma and adenoma. The intestinal-type gastric carcinoma is associated with atrophic gastritis and IM.     

白细胞介素-1B-511单核苷酸多态性与胃癌关系的流行病学研究

目的研究中国胃癌高、低发区白细胞介素（IL）-1B-511单核苷酸多态性、幽门螺杆菌（Hp）感染与胃癌的芙系。方法胃癌高发区（陕西省）胃癌患者、健康志愿者各102例，胃癌低发区（广东省）胃癌患者、健康志愿者各104例，两组人群在性别比及年龄上均匹配。采用限制性片段长度多态性（PCR—RFLP）分析IL-1B-511单核苷酸多态性，酶联免疫吸附法（ELISA）检测血清抗Hp—IgG抗体。结果在胃癌低发区，胃癌患者IL-1B-511T／T基因型频率明显高于对照人群（26．9％比13．4％，X^2=5．85，P〈0．05；OR=2．37，95％CI为1．16～4．82）。在胃癌高发区，胃癌患者IL-1B-511 T／T基因型频率与对照人群尢明显差异（27．5％比24．5％，X^2=0．41，P〉0．05）；高发区对照人群的IL-1B-511 T／T基因型频牢明显高于低发区相应人群（24．5％比13．4％，X^2=4．1，P〈0．05）。Hp感染轻度增加低发区人群发生胃癌的危险性（OR=3．03，95％CI为1．61～5．71），而IL-1B-511 T／T基因型增加Hp感染后胃癌发生的危险性（OR=8．0，95％CI为1．39～35．7）。结论IL-1B-511 T／T基因型与中国人胃癌发生有关，IL-1B-511 T／T基因型增加HP感染后胃癌发生的危险性。     

Etiologic factors of gastric cardiac adenocarcinoma among men in Taiwan

AIM: To elucidate etiologic associations between Helicobacter pylori ( H pylori), lifestyle, environmental factors and gastric cardiac adenocarcinoma (GCA) among men.METHODS: A hospital-based case-control study was conducted in Taiwan from 2000 to 2009.All cases were newly confirmed as primary GCA.Five controls were selected matching with age, sex, and admission date to each case.Participants were informed of potential risk factors with a structured questionnaire by trained interviewers during hospitalization and provided a blood sample for the determination of H pylori infection.Odds ratio (OR) and 95% confidence interval (95% CI) were used to evaluate risk, and a multivariate conditional logistic regression model was performed.RESULTS: All participants recruited for this study were men, consisting of 41 cases and 205 controls.Results of the univariate analysis showed that significant factors associated with the etiology of GCA included H pylori (OR = 2.69, 95% CI = 1.30-5.53), cigarette smoking (OR = 2.28, 95% CI = 1.05-4.96), working or exercising after meals (OR = 3.26, 95% CI = 1.31-8.11), salted food (OR = 2.51, 95%CI = 1.08-6.11), fresh vegetables (OR = 0.28, 95% CI = 0.09-0.80), fruits (OR = 0.19, 95% CI = 0.04-0.89), and rice as principal food (OR = 0.53, 95% CI = 0.30-0.85).Multivariate conditional logistic regression models indicated that a significantly elevated risk of contracting GCA was associated with working or exercising after meals (OR = 3.18, 95% CI = 1.23-9.36) and H pylori infection (OR = 2.93, 95% CI = 1.42-6.01).In contrast, the consumption of fresh vegetables (OR = 0.22, 95% CI = 0.06-0.83), fruits (OR = 0.28, 95% CI = 0.09-0.79) and rice as principal food (OR = 0.48, 95% CI = 0.24-0.93) remained as significant beneficial factor associated with GCA.CONCLUSION: Working or exercising after meals and H pylori infection increase the risk of GCA, but higher intakes of rice, fresh vegetables and fruits reduce the risk.     

A case-control study of association of Helicobacter pylori infection with morbid obesity in Taiwan

BACKGROUND: Obesity is an increasing health problem in developed countries, where the prevalence of Helicobacter pylori infection is decreasing. Recent studies suggested colonization of the stomach by H pylori might affect gastric expression of appetite- and satiety-related hormone and patients cured of H pylori infection gained weight. It was hypothesized that H pylori could be a contributing pathogenic factor in childhood and adult obesity. METHODS: To determine whether H pylori infection is linked to obesity, a case-control study composed of 414 patients with morbid obesity (a body mass index [calculated as weight in kilograms divided by the square of height in meters] of > or = 35 with serious comorbidity or a body mass index of > or = 40) and 683 control subjects (a body mass index of <25) with a comparable socioeconomic status was conducted. Immunoglobulin G antibodies against H pylori were measured from frozen serum samples by an enzyme-linked immunosorbent assay. Logistic regression was used to calculate the odds ratio (OR) and 95% confidence interval (CI). RESULTS: The overall seropositivity was significantly lower in obese patients (181 [43.7%] of 414) than controls (410 [60.0%] of 683) (OR, 0.50; 95% CI, 0.39-0.65; P<.001). Differences in the estimated risk of the presence of H pylori were more pronounced in younger age groups, with ORs of 0.32 (95% CI, 0.10-1.00; P = .05) in those aged 10 to 19 years, 0.55 (95% CI, 0.34-0.89; P = .01) in those aged 20 to 29 years, 0.49 (95% CI, 0.30-0.80; P = .007) in those aged 30 to 39 years, and 0.58 (95% CI, 0.33-1.00; P = .05) in those aged 40 years or older. CONCLUSIONS: Our data indicated an inverse relationship between morbid obesity and H pylori seropositivity. These findings raise the hypothesis that a lack of H pylori infection, especially during childhood, might enhance the risk of the development of morbid obesity.     

Meta-analysis of the relationship between cagA seropositivity and gastric cancer

BACKGROUND & AIMS: Reports in the literature regarding the relationship of infection with cagA -positive strains of Helicobacter pylori to gastric cancer over and above H. pylori infection alone are conflicting. The aim of this study was to estimate the magnitude of the risk for gastric cancer associated with cagA seropositivity and to identify any sources of heterogeneity between studies. METHODS : A meta-analysis of case-control studies with age- and sex-matched controls, which provided raw data on the infection rates with H. pylori and cagA strains of H. pylori as detected by serology or polymerase chain reaction DNA, was performed. RESULTS : A comprehensive literature search identified 16 qualified studies with 2284 cases and 2770 controls. H. pylori and cagA seropositivity significantly increased the risk for gastric cancer by 2.28- and 2.87-fold, respectively. Among H. pylori -infected populations, infection with cagA -positive strains further increased the risk for gastric cancer by 1.64-fold (95% confidence interval [CI], 1.21-2.24) overall and by 2.01-fold (95% CI, 1.21-3.32) for noncardiac gastric cancer. Gastric cancer at the cardia is not associated with H. pylori infection or cagA -positive strains of H. pylori. Patient age and site of gastric cancer contributed to the heterogeneity between studies. CONCLUSIONS: Infection with cagA -positive strains of H. pylori increases the risk for gastric cancer over the risk associated with H. pylori infection alone. Searching for cagA status over H. pylori infection may confer additional benefit in identifying populations at greater risk for gastric cancer.     

Lack of association between seroprevalence of Helicobacter pylori infection and primary biliary cirrhosis

AIM: To determine the association between seroprevalence of Helicobacter pylori (H pylori) infection and primary biliary cirrhosis (PBC). METHODS: In this case-control study, 149 consecutive patients (10 males, 139 females, mean age 58.2+/-11 years, range 26-82 years) suffering from PBC and 619 consecutive healthy volunteer blood donors (523 males, 96 females, mean age 47+/-5.3 years, range 18-65 years) attending the Hospital Blood Bank and residing in the same area were recruited. A commercial enzyme linked immunosorbent assay was used to detect anti-H pylori (IgG) antibodies in serum. RESULTS: Antibodies to H pylori were present in 78 (52.3%) out of 149 PBC-patients and in 291 (47%) out of 619 volunteers (P = 0.24, OR 1.24, 95% CI 0.85-1.80). In the subjects less than 60 years old, the prevalence of H pylori infection among PBC-patients (40/79) was slightly higher than in controls (50.6% vs 46.2%) P = 0.46, OR = 1.19, 95% CI: 0.72-1.95). In those over 60 years, the prevalence of H pylori infection was similar between PBC-patients and controls (54.2% vs 57.8%, P = 0.7, OR 0.86, 95% CI 0.36-2.07). CONCLUSION: There is no association between seroprevalence of H pylori infection and primary biliary cirrhosis.     

A novel genetic polymorphism of inducible nitric oxide synthase is associated with an increased risk of gastric cancer

AIM: Inducible nitric oxide synthase (iNOS) plays a central role in the pathway of reactive oxygen and nitrogen species metabolism when Helicobacter pylori (H pylon) infection occurs in humans, iNOS Ser^608 Leu allele, a novel genetic polymorphism (C/T) occurring within exon 16 of the iNOS reductase domain, may have a dramatic effect on the enzymatic activity. The aim of this study was to determine whether iNOS C/T polymorphism was associated with increased susceptibility to gastric cancer. METHODS: We conducted a population based case-control study in a high gastric cancer incidence area, Yangzhong, China. Questionnaires from 93 patients with intestinal type gastric cancer (IGC), 50 with gastric cardia cancer (GCC) and 246 healthy controls were obtained between 1997 and 1998, and iNOS genotyping was carried out. Odds ratios (ORs), interaction index (γ), and 95% confidence intervals for the combined effects of iNOS genotype and H pylori infection, cigarette smoking or alcohol drinking were estimated. RESULTS: The frequency of (CT+TT) genotypes was higher in cases than in control group (24.48% vs 23.17%), but the difference was not statistically significant. After adjusting for age and gender, past cigarette smokers with (CT+TT) genotypes had a significantly increased risk of IGC (OR=3.62, 95% CI:1.23-10.64), while past alcohol drinkers with (CT+TT) genotypes had a significantly increased risk of GCC (OR=3.33, 95% CI:1.14-9.67). H pylori CagA negative subjects with (CT+TT) genotypes had a significantly increased risk of both IGC and GCC (OR=2.19 and 3.52, respectively). CONCLUSION: iNOS Ser^608 Leu allele may be a potential determinant of susceptibility to cigarette -alcohol induced gastric cancer, but larger studies are needed to confirm the observations.     

Inducible nitric oxide synthase polymorphism is associated with the increased risk of differentiated gastric cancer in a Japanese population

INTRODUCTION Gastric cancer is the second most frequent cancer in the world, accounting for a large proportion of cancer cases in Asia, Latin America, and some countries in Europe[1]. H pylori strains carrying the cytotoxin-associated gene A (cagA) are st…     

Role of environmental and genetic factor interaction in age-related disease development: the gastric cancer paradigm

The association of Helicobacter pylori (Hp) infection with gastric cancer is well known and might be considered a paradigmatic example of the role that interaction among environmental factors and individual background might play in inducing age-associated disease. To evaluate the role of interaction of Hp infection with genetic background, gastric cancer and chronic gastritis patients as well as random selected controls were typed for five inflammation-related polymorphisms of IL-1 and IL-10 cytokine genes. No association among IL-10 or IL-1 variants with an increased risk of gastric cancer was found, whereas an Hp-independent association of IL-1beta -511T positive genotypes to an increased risk of chronic gastritis was found (Hp-/511T+ OR 1.89, 95% CI: 1.01-3.54; Hp+/-511T+ OR 1.83, 95% CI: 1.05-3.19). Stratification of gastric cancer group according to Hp infection does not allow finding a statistically significant association of Hp+ to the higher histological grading (G3) of gastric cancer (OR 1.54, 95% CI: 0.46-5.11). Our findings seem to confirm that cytokine genetic variants might contribute to determining the background for inflammaging in which H. pylori infection might facilitate cancer development.