Association of diet and place of birth with stomach cancer incidence in Hawaii Japanese and Caucasians.

Stomach cancer incidence rates were compared among four groups: Japanese in Japan, Japanese in Hawaii, Caucasians in Hawaii, and all American whites. The highest rates at all ages occurred in the Japan Japanese, followed next by the Hawaii Japanese. Hawaii Caucasians tended to have similar age-specific rates to American whites in general. When the Japanese and Caucasians in Hawaii were divided by place of birth, the Japanese migrants to Hawaii had higher age-adjusted incidence rates than the Japanese born in Hawaii, while the Caucasian migrants to Hawaii (chiefly from the United States mainland) had lower rates than the Caucasians born in Hawaii. Examination of dietary data in relation to the place-of-birth-specific incidence rates showed positive association of stomach cancer with consumption of rice, pickled vegetables, and dried/salted fish, and a negative association with vitamin C intake. The results are consistent with the particular hypothesis that stomach cancer is caused by endogenous nitrosamine formation from dietary precursors, and that vitamin C may protect against the disease.