Case-control study of dietary pattern and other risk factors for gastric cancer

Helicobacter pylori in Human Stomach: The Inconsistencies in Clinical Outcomes and the Probable Causes

Pathogenic potentials of the gastric pathogen, Helicobacter pylori, have been proposed, evaluated, and confirmed by many laboratories for nearly 4 decades since its serendipitous discovery in 1983 by Barry James Marshall and John Robin Warren. Helicobacter pylori is the first bacterium to be categorized as a definite carcinogen by the International Agency for Research on Cancer (IARC) of the World Health Organization (WHO). Half of the world’s population carries H. pylori, which may be responsible for severe gastric diseases like peptic ulcer and gastric cancer. These two gastric diseases take more than a million lives every year. However, the role of H. pylori as sole pathogen in gastric diseases is heavily debated and remained controversial. It is still not convincingly understood, why most (80–90%) H. pylori infected individuals remain asymptomatic, while some (10–20%) develop such severe gastric diseases. Moreover, several reports indicated that colonization of H. pylori has positive and negative associations with several other gastrointestinal (GI) and non-GI diseases. In this review, we have discussed the state of the art knowledge on “H. pylori factors” and several “other factors,” which have been claimed to have links with severe gastric and duodenal diseases. We conclude that H. pylori infection alone does not satisfy the “necessary and sufficient” condition for developing aggressive clinical outcomes. Rather, the cumulative effect of a number of factors like the virulence proteins of H. pylori, local geography and climate, genetic background and immunity of the host, gastric and intestinal microbiota, and dietary habit and history of medicine usage together determine whether the H. pylori infected person will remain asymptomatic or will develop one of the severe gastric diseases.

Validation of a Dietary Inflammatory Index (DII) and Association with Risk of Gastric Cancer: a Case-Control Study

Background:

Gastric cancer (GC) is the fifth most common malignancy and the second leading cause of cancer-related deaths worldwide. Studies have shown that dietary components and inflammation are implicated in the etiology of GC.

Methods:

We examined the ability of a dietary inflammatory index (DII) to predict the odds of GC in a case-control study conducted from December 2014 to May 2016. The subjects were 82 cases and 95 controls who attended specialized centers in Tabriz, Iran. DII scores were computed from a validated 168-item food frequency questionnaire. Logistic regression models were used to estimate odds ratios (ORs) adjusted for age, sex, body mass index, education, smoking, alcohol, H.pylori infection, physical activity, aspirin/NSAID use and total caloric intake.

Results:

In the fully adjusted model, subjects with a DII score >-1.77 had nearly 3.5 times higher odds of having GC compared with subjects with DII≤-1.77, (ORDII>-1.77≤-1.77=3.39; 95%CI=1.59, 7.22). Also, for every one-unit increase in DII, there was a corresponding increase in hs-C-reactive protein, tumor necrosis factor-alpha, interleukin (IL)-6 and IL-1b: β=0.09, 0.16, 0.16 and 0.10, respectively; and a corresponding decrease in IL-10: β=-0.11.

Conclusion:

Subjects who consumed a more pro-inflammatory diet were at increased odds of GC compared to those who consumed a more anti-inflammatory diet.

Risk Factors for Gastric Cancer: A Systematic Review

Objective: Gastric cancer is one of the leading causes of death worldwide, with many influences contributing to the disease. The aim of this study was to identify the most important risk factors. Methods: This study was conducted in 2017 with a structured overview in the Science Directe, Scopus, PubMed, Cochrane, Web of Science (ISI) databases. In the first step, articles were extracted based on their titles and abstracts; the quality of 43 articles was evaluated using the STORBE tool. Inclusion criteria were studies carried out on human, English language (first step), year of the study and the study type (second step). Results: Finally, 1,381 articles were found, of which 1,269 were excluded in primary and secondary screening. In reviewing the references of the remaining 44 papers, 4 studies were added. Finally, 43 articles were selected for the quality assessment process. A total of 52 risk factors for gastric cancer were identified and classified into nine important categories: diet, lifestyle, genetic predisposition, family history, treatment and medical conditions, infections, demographic characteristics, occupational exposures and ionizing radiation’. Conclusion: Several environmental and genetic factors are involved in the development of gastric cancer. Regarding the role of changes in ‘diet and lifestyle’, considering appropriate nutrition and improving the level of education and awareness of people is vital for early diagnosis and timely treatment of this disease, especially in people with a family history and genetic predisposition.

Design a Fuzzy Rule-based Expert System to Aid Earlier Diagnosis of Gastric Cancer

INTRODUCTION

Screening and health check-up programs are most important sanitary priorities, that should be undertaken to control dangerous diseases such as gastric cancer that affected by different factors. More than 50% of gastric cancer diagnoses are made during the advanced stage. Currently, there is no systematic approach for early diagnosis of gastric cancer.

OBJECTIVE

to develop a fuzzy expert system that can identify gastric cancer risk levels in individuals.

METHODS

This system was implemented in MATLAB software, Mamdani inference technique applied to simulate reasoning of experts in the field, a total of 67 fuzzy rules extracted as a rule-base based on medical expert's opinion.

RESULTS

50 case scenarios were used to evaluate the system, the information of case reports is given to the system to find risk level of each case report then obtained results were compared with expert's diagnosis. Results revealed that sensitivity was 92.1% and the specificity was 83.1%.

CONCLUSIONS

The results show that is possible to develop a system that can identify High risk individuals for gastric cancer. The system can lead to earlier diagnosis, this may facilitate early treatment and reduce gastric cancer mortality rate.

An Update on Helicobacter pylori as the Cause of Gastric Cancer

BACKGROUND

Gastric cancer is the second most common cause of cancer deaths worldwide. The vast majority of gastric cancers are inflammation-related cancers caused by infection with Helicobacter pylori. H. pylori-induced oxidative stress damages DNA, resulting in genetic instability. In addition, H. pylori itself can cause DNA damage and epigenetic changes that trigger genetic instability and neoplastic transformation.

SUMMARY

H. pylori strain-specific components act in combination with host factors and environmental and dietary factors to greatly enhance the inflammatory response and thus the cancer risk. Variations in several key factors, such as the cag pathogenicity island and the VacA protein, can trigger a greater inflammatory response in host cells. Genetic polymorphisms in the host such as in the IL-1β gene, and chromosomes 9p21.3 and 10q23 also play a contributing role. Finally, diet is a major external factor that modulates the risk of gastric cancer.

KEY MESSAGE

The majority of gastric cancers are inflammation-related cancers caused by infection with H. pylori. Eradication of H. pylori is important for the prevention and treatment of gastric cancer.

PRACTICAL IMPLICATIONS

H. pylori eradication results in healing of gastritis and prevention of further H. pylori-induced genetic damage. Eradication of H. pylori prior to development of atrophic gastritis can prevent the development of gastric cancer. Japan has undertaken a nationwide program to identify and eliminate H. pylori, along with surveillance for those who underwent H. pylori eradication too late to eliminate cancer risk. Population-wide eradication of H. pylori will result in gastric cancer becoming a vanishingly rare disease.