Dietary and smoking habits were examined in 66,707 participants in a mass screening test for stomach cancer in Saitama, Japan. Eighty-eight participants with stomach cancer, diagnosed by barium X-ray examination and histologically verified after endoscopic examination, were compared with the remaining 66,619 participants, in a case-control study. In a food consumption frequency questionnaire, dietary habits were investigated on the basis of intake of six individual food items : rice, miso soup,

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... boiled fish, pickled vegetables, nuts, and seaweed ; and seven food groups : potatoes, soybean products (except miso soup), fruits, green-yellow vegetables, white vegetables, raw vegetables, and fish/shellfish (all types) ; together with current cigarette smoking status and individual preference for salty foods. There was no substantial association between the risk of stomach cancer and the consumption of any dietary item, except for the consumption of rice (four or more bowls per day, RR=0.2 ; CI : 0.1 to 0.6). Neither was an increase in risk from cigarette smoking found. The risk score assessment revealed no correlation between risk and risk scores. In spite of the limitations of the present study, our findings seem to support the view that the lifestyles of stomach cancer patients found in the mass study were different from those of stomach cancer patients found in hospitals. J Epidemiol, 1994; 4 : 59-63. case-control, diet, smoking, stomach cancer The mortality rate for stomach cancer has fallen gradually in Japan, possibly following the westernization of food intake in this country1). Western-type foods, i.e. milk products, animal meats, fatty foods, raw vegetables, and fruits have been more frequently consumed than ever while the main Japanese traditional foods, i.e. rice and salty foods have been consumed less so. Diet has been a main focus in the epidemiology of stomach cancer, and it has been suggested that diets high in salt and low in raw vegetables and fruits increase the risk of this cancer. Evidence for this is inconclusive, however, because of inconsistent findings2,3). In recently published studies on stomach cancer, the relative risks of etiological factors are usually around 2. Trichopoulos et al .4) and La Vecchia et al.5) have found that a clearer picture of risk is obtained if food items associated with stomach cancer are considered jointly. Even the simple addition of a few items led to a marked increase ; for example, individuals with a low frequency of vegetable and fruit consumption and high intake of starchy foods had almost 7 times the risk of stomach cancer than those reporting high vegetable/fruit and low starch intake (RR=6.9 ; 95% CI=3.7-13.1)5). Our previous studies 6,7) showed that current cigarette smoking, preference for salty foods, and the consumption of rice, miso soup, boiled fish, and pickled vegetables were positively related, and the consumption of nuts, seaweed, potatoes, soybean products, fruits, green-yellow vegetables, white vegetables, raw vegetables, and fish/shellfish were inversely related to the risk of stomach cancer, and the same clear picture of risk was observed in a combined risk score (RR=5.3; 95% CI=3.2-8.6; trend P<0.01). The aim of the present study was to examine whether our previous observation could be reproduced in a different set of population. MATERIALS AND METHODS Saitama Prefecture had a total population of 6,400,000 in 1990 in 92 cities, towns, and villages. Of the residents