1 nested case-control study on the relationship between Helicobacter pylori antibody and gastric cancer:
In 2000, the Institute of Oncology of the Chinese Academy of Medical Sciences and the National Cancer Institute of the United States cooperated with the nutritional intervention trial cohort of the general population in Lin County and the serum samples collected and preserved before the intervention. a nested case-control study on the relationship between Helicobacter pylori antibody and gastric cancer was conducted. It was found that Helicobacter pylori seropositive could increase the risk of gastric cancer by two times. To the best of our knowledge, this is the first prospective study to demonstrate a positive statistical association between Helicobacter pylori serum antibodies (whole-cell and CagA antibodies) and gastric cardiac adenocarcinoma. Although the number of cardiac and non-cardiac cancer cases in this study is the largest in reported studies, the use of serum antibodies including both whole-cell and CagA antibodies makes the study more convincing. However, because the observation time is not long enough, continuing to follow up this cohort will provide more valuable evidence for verifying the causal relationship between gastric cancer, including cardiac and non-cardiac cancer, and Helicobacter pylori infection. Kamangar et al. (2007) used the nutritional intervention trial cohort of the general population in Linxian County to follow up to 2001. a further nested case-control study was conducted between 343 gastric cancer cases and 992 controls. It was found that the OR=1.61 (95%CI: 1.15-2.21) of Helicobacter pylori antibody positive and non-cardiac gastric cancer (95%CI: 1.15-2.21) changed with the follow-up time, less than 5 years OR= 2.32 (95%CI: 1.35-3.97). 5-10 years OR= 1.23 (95%CI:0.77~1.98), > 10 years OR= 1.27 (95%CI: 0.78-2.08), once again proved the role of this bacteria in the pathogenesis of non-cardiac gastric cancer. At the same time, the study also detected and compared 582 cases of cardiac cancer, found that Helicobacter pylori positive and cardiac cancer OR=1.64 (95% CI: 1.26: 2.14), indicating that Helicobacter pylori infection is also related to cardiac cancer, which is different from the research results in developed countries.2 Helicobacter pylori infection increases the risk of gastric cancer:Yuan et al. (1999) reported the results of a prospective cohort study in Shanghai, China, that Helicobacter pylori infection was not found to be associated with the subsequent risk of gastric cancer in 1996. Helicobacter pylori serum antibodies were then detected using the ELISA method based on Shanghai rather than the UK-based method previously used. The results showed that there was a statistically significant correlation between gastric cancer and Helicobacter pylori seropositive (OR= 1.84; 95%CI: 1.08-3.11), and it increased with the increase of observation time. After follow-up for more than five years, it was found that the odds ratio of gastric cancer to Helicobacter pylori seropositivity was 3.74 (95%CI:1.51~9.30). Both cardiac and non-cardiac cancers were related to Helicobacter pylori infection. You et al. (2000) A cohort study conducted in Linyi County, Shandong Province, an area with a high incidence of gastric cancer in China, found that positive serum Helicobacter pylori antibody could increase the risk of heteroplasia or gastric cancer (OR = 1. 8) 95% CI: 1. 2 to 2. 6 (P < 0.003). In addition, a cohort study conducted by Hsu et al. (2007) in Taiwan Province of China also found that Helicobacter pylori infection (histology and rapid urea test) can increase the risk of gastric adenocarcinoma.
