[Helicobacter pylori infection and gastric cardia cancer: a nested case-control study].

ABSTRACT

OBJECTIVE: To explore the association of Helicobacter pylori infection with gastric cardia cancer. METHODS: An unmatched prospective nested case-control study was conducted. In 1985, 29 584 subjects in age of 40-69 were recruited from Linxian, Henan Province. 10 mL blood samples were collected from all participants. By March 2001, 1089 cases of gastric cardia cancer were diagnosed. 196 cases were randomly sampled from them and formed the case group. 185 subjects were randomly sampled from the subcohort, which was built up in a previous case-cohort study and was able to represent the baseline population, forming the control group. Serum samples were assayed for H. pylori IgG antibodies by enzyme-linked immunosorbent assay. The adjusted odds ratio (OR) and 95% confidence interval (95% CI) were calculated for cardia cancer, and also calculated by time from blood collection, time to diagnosis, gender and age, when blood was taken. RESULTS: The positive rate of H. pylori IgG antibodies in control and case groups was 71.4% and 82.1%, respectively. The adjusted OR (95% CI) were 2.00 (1.21-3.31) for all cardia cancer cases, 1.36 (0.71-2.60) for male subjects, and 4.19 (1.73-10.17) for female subjects. By age group when blood samples were collected, the adjusted OR (95% CI) were 3.45 (1.41-8.45), 1.56 (0.69-3.54) and 1.11 (0.37-3.33) for < or = 50, 51-60 and > 60-years-old groups, respectively. The adjusted OR (95% CI) were 1.78 (0.88-3.60), 1.66 (0.80-3.44) and 2.23 (1.05-4.74) for cases diagnosed < or = 5, 6-10 and > 10 years after blood collection, respectively. CONCLUSION: H. pylori infection is associated with gastric cardia cancer, especially for female subjects, the ones who were younger than 50 years old and who were infected with H. pylori more than 10 years.