Researchers investigated the importance of tobacco smoking and Helicobacter pylori infection as risk factors in the development of gastric carcinoma.
Blood samples, and a questionnaire on smoking habits, were collected from a cohort of 32,906 individuals during a health screening program from 1974 to 1992.
| Risk of gastric cancer is 11 times greater in H. pylori-infected current smokers.
| Scandinavian Journal of Gastroenterology |
56 cases of gastric cancer and 224 matched controls were selected for the study. The mean interval between screening and cancer diagnosis was 5.7 years.
The researchers determined H. pylori infection by IgG-serology.
The proportion of current smokers was found to be 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 were found to have an odds ratio (OR) of 2.2. With different levels of tobacco consumption, smoking less than 20g tobacco each day gave the OR of 2.1 and the OR when smoking more than 20g tobacco per day was 2.5.
Subjects with H. pylori infection were five times more likely to develop gastric carcinoma. Among H. pylori seropositive citizens, current smoking was associated with an increased risk of 2.3 compared with non-smoking H. pylori-positive persons.
Researcher J. H. Simán and colleagues commented, "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," they concluded.