A case-cohort study of diet and stomach cancer.

In this case-cohort study, from 1965 to 1968, 8006 Hawaiian men of Japanese ancestry were interviewed with a 24-h dietary recall questionnaire. After a follow-up period of 18 years, 111 stomach cancer incident cases were identified. Dietary data from these patients and from 361 cancer-free men were analyzed for intake of selected foods, food groups, and nutrients. We found that the consumption of all types of vegetables was protective against stomach cancer. Specifically, subjects in the highest group of vegetable consumption (greater than or equal to 80 g/day) had a relative risk of 0.6 (95% confidence interval, 0.3-0.9) in comparison with nonconsumers. This statistically significant inverse trend persisted after adjustment for age at examination and cigarette-smoking status. Similar but weaker protective effects from consumption of green and cruciferous vegetables were also observed. In addition, an inverse association between stomach cancer risk and intake of fruits was noted (P = 0.05), but this inverse trend was weakened after the effect of cigarette smoking was taken into account. There were no other dietary factors significantly associated with the risk of gastric cancer.