The role of dietary factors in the intestinal and diffuse histologic subtypes of gastric adenocarcinoma: a case-control study in the U.S.

BACKGROUND: The decline of gastric adenocarcinoma in the U. S. and the parallel decrease in the predominance of the intestinal type of gastric adenocarcinoma may reflect, in part, changes in diet over the last 60 years. Because the intestinal and diffuse types of gastric adenocarcinoma may be epidemiologically distinct, the authors hypothesized that different nutritional factors are associated with the different subtypes of gastric adenocarcinoma.
METHODS: Ninety-one incident cases with a pathologic diagnosis of gastric adenocarcinoma and 132 cancer free controls were included in this study. All cases were defined as being either the intestinal or diffuse type of gastric adenocarcinoma. Epidemiologic data were collected by a modified National Cancer Institute Health Habits History Questionnaire. Nutritional and dietary factors were analyzed using a logistic regression model.
RESULTS: Several dietary factors were significantly associated with both subtypes of gastric adenocarcinoma, including dietary intakes of fiber, oleic acid, potassium, and fruits. Almost all dietary factors and food groups unique to intestinal gastric adenocarcinoma were protective in nature (vitamin B6, folate, niacin, iron, noncitrus fruits, and raw fruit), except for a high intake of dietary calories, which was a risk factor for intestinal gastric adenocarcinoma. The unique factors found to be protective for diffuse disease were carbohydrate and vitamin C intake.
CONCLUSIONS: This study suggests that dietary factors contribute to the carcinogenesis of gastric adenocarcinoma. It also appears that although dietary risk and protective factors are common to both the intestinal and diffuse types of this malignancy, protective dietary factors may play a more important role in preventing the intestinal type of gastric adenocarcinoma.