Ethnic differences in Helicobacter pylori infection

Prevalence of Helicobacter pylori infection in advanced gastric carcinoma

BACKGROUND

[corrected] There is substantial evidence that infection with Helicobacter pylori plays a role in the development of gastric cancer and that it is rarely found in gastric biopsy of atrophic gastritis and gastric cancer. On advanced gastric tumors, the bacteria can be lost from the stomach.

AIMS

To analyze the hypothesis that the prevalence of H.pylori in operated advanced gastric carcinomas and adjacent non-tumor tissues is high, comparing intestinal and diffuse tumors according to Lauren's classification

METHODS

A prospective controlled study enrolled 56 patients from "Hospital Universitário", Federal University of Rio Grande do Norte, Natal, RN, Brazil, with advanced gastric cancer, treated from February 2000 to March 2003. Immediately after partial gastrectomy, the resected stomach was opened and several mucosal biopsy samples were taken from the gastric tumor and from the adjacent mucosa within 4 cm distance from the tumor margin. Tissue sections were stained with hematoxylin and eosin. Lauren's classification for gastric cancer was used, to analyse the prevalence of H. pylori in intestinal or diffuse carcinomas assessed by the urease rapid test, IgG by ELISA and Giemsa staining. H. pylori infected patients were treated with omeprazole, clarithromycin and amoxicillin for 7 days. Follow-up endoscopy and serology were performed 6 months after treatment to determine successful eradication of H. pylori in non-tumor tissue. Thereafter, follow-up endoscopies were scheduled annually. Chi-square and MacNemar tests with 0.05 significance were used.

RESULTS

Thirty-four tumors (60.7%) were intestinal-type and 22 (39.3%) diffuse type carcinomas. In adjacent non-tumor gastric mucosa, chronic gastritis were found in 53 cases (94.6%) and atrophic mucosa in 36 patients (64.3%). All the patients with atrophic mucosa were H. pylori positive. When examined by Giemsa and urease test, H. pylori positive rate in tumor tissue of intestinal type carcinomas was higher than that in diffuse carcinomas. In tumor tissues, 34 (60.7%) H. pylori-positive in gastric carcinomas were detected by Giemsa method. H. pylori was observed in 30 of 56 cases (53.5%) in tissues 4 cm adjacent to tumors. This difference was not significant. Eradication of H. pylori in non-tumor tissue of gastric remnant led to a complete negativity on the 12th postoperative month

CONCLUSIONS

The data confirmed the hypothesis of a high prevalence of H. pylori in tumor tissue of gastric advanced carcinomas and in adjacent non-tumor mucosa of operated stomachs. The presence of H. pylori was predominant in the intestinal-type carcinoma.

Community-based familial study of Helicobacter pylori infection among healthy Japanese Brazilians

BACKGROUND

The present study of Helicobacter pylori infection was conducted in family units of Japanese Brazilians living in São Paulo city. The authors attempted to determine the seroprevalence of H. pylori infection within family units of Japanese Brazilians and to identify risk factors associated with intrafamilial transmission.

METHODS

The seroprevalence was determined in 1037 healthy and asymptomatic volunteer subjects aged 0-69 years (530 adults and 507 children) of 265 families. Demographic data and details of living conditions were obtained from each family.

RESULTS

H. pylori seropositive infection was found in 39.2% of the parents and 9.3% of the children. A reduced risk of H. pylori infection was found for girls (odds ratio [OR] 0.45; 95% confidence interval [CI], 0.23-0.86). The prevalence of infection was 3.5% for children with uninfected parents; 9.9% (OR, 2.51; 95% CI, 0.95-6.61) for those with a seronegative mother and a seropositive father; 14.9% (OR, 4.93; 95% CI, 1.86-13.06) for those with a seropositive mother and a seronegative father; and 16.0% (OR, 5.29; 95% CI, 1.98-14.14) for those with seropositive parents. On multivariate analysis, the use of a pacifier, and mother's symptoms of nausea and vomiting were significantly associated with the risk of H. pylori infection for children, and the child having her/his own room was significantly associated with a reduced risk. Income was not associated with H. pylori infection in children and was inversely associated in parents.

CONCLUSION

The prevalence of H. pylori infection in family units of Japanese Brazilians supports the hypothesis of a predominant role for mother-child transmission of H. pylori infection, mainly through contact with regurgitated gastric juice in the mother's mouth.

Implications of Helicobacter pylori infection for stomach cancer prevention

Accumulating evidence has implicated Helicobacter pylori, an established cause of chronic gastritis and peptic ulcer, in the etiology of gastric cancer. Control of this infection would reduce the occurrence of chronic gastritis and peptic ulcer and might substantially lower the risk of stomach cancer as well. The public health impact of this infectious agent warrants efforts to identify preventive measures. This paper reviews the evidence linking H. pylori infection to gastric cancer and evaluates the potential for control in high-risk populations. Current obstacles to H. pylori control are discussed, including the link to poor socioeconomic conditions, difficulty in identifying incident cases, lack of natural immunity to reinfection, limited effectiveness of antibiotic therapy in high-prevalence populations, and incomplete knowledge regarding the reservoir of infection, mode of transmission, host susceptibility factors, and the potential for developing an effective vaccine. Worthwhile avenues of research include studies designed to identify modifiable risk factors for acquisition of the infection, modifiable host factors that may increase resistance to chronic infection, more effective antibiotic therapies, and effective vaccines.

Helicobacter pylori disease in childhood

Helicobacter pylori (H. pylori) is responsible for one of the most frequently encountered infectious diseases worldwide. H. pylori infection can lead to the development of gastritis and peptic ulcer disease. The presence of H. pylori in the human stomach also represents an increased risk for gastric cancer and gastric lymphoma. Epidemiologic data obtained in adults suggest that the actual colonization with H. pylori is in fact determined by childhood factors. Therefore, the pediatric age group represents the ideal target population for studies concerning the pathogenesis and epidemiology of H. pylori infection.