In this study, researchers from Stanford, California, prospectively evaluated whether Helicobacter pylori infection protects against adenocarcinoma of the esophagus.
Dr Catherine deMartel and colleagues performed a nested case-control study among 128,992 subscribers to a health maintenance program. Subscribers had participated in a multiphasic health checkup between 1964 and 1969.
During follow-up of this cohort, 52 individuals were diagnosed with adenocarcinoma of the esophagus.
|Smoking is a strong independent risk factor for esophageal cancer.|
|American Gastroenterological Association|
The research team gathered controls, who had not developed cancer during the interval period, from 4 previous studies conducted in the cohort. The previous studies were of gastric lymphoma, gastric cancer, colorectal cancer, and myocardial infarction.
The team also collected data on cigarette use, alcohol consumption, race, and education level using self-administered questionnaires at the time of enrollment in the study.
They additionally, tested serum samples, collected at enrollment, for IgG antibodies against H. pylori and for IgG antibodies against the CagA gene product of H. pylori.
All analyses were adjusted for age, gender, race, date of serum collection, and site of enrollment in the cohort.
The researchers found that the mean interval between enrollment and diagnosis of adenocarcinoma was 19.2 years.
They determined that the subjects infected with H. pylori were significantly less likely to develop esophageal adenocarcinoma, when compared with uninfected subjects.
The results were similar for each control group (Table 1).
|Cases||All controls||Lymphoma||Colon cancer||Gastric cancer||Heart study|
|* OR adjusted for age, gender, race, and site of enrollment.|
* * OR adjusted for age, gender, race, site of enrollment, cigarette smoking, alcohol consumption, and education level.
However, in all models, the researchers identified cigarette smoking and higher body mass index as strong independent risk factors for esophageal adenocarcinoma (OR = 7).
The research team concluded that H. pylori infection is associated with decreased risk of esophageal adenocarcinoma. Cigarette smoking and body mass index were also strong independent risk factors.