Dietary factors and stomach cancer in Spain: a multi-centre case-control study.

A multi-centre case-control study of diet and gastric cancer was carried out in 4 regions of Spain (Aragon, Castile, Catalonia and Galicia). We selected 354 cases of pathologically confirmed gastric adenocarcinoma from 15 hospitals, representative of nearly all those in the study areas. A control for each case, matched by age, sex and area of residence, was selected from the same hospital as the case. Habitual diet was investigated by the dietary history method, and past diet by means of a frequency questionnaire. The results regarding consumption of food items are presented here. With respect to habitual diet, an increase in risk was associated with consumption of preserved fish, cold cuts and oleaginous fruits. A high intake of cooked green vegetables, fresh noncitrus fruit and dried fruit showed an inverse association with the risk of gastric cancer. Simultaneous intake of 2 groups of food which increase or decrease the risk of cancer strengthens the respective individual effect. The intake of protective food items seems to neutralize the effects of food items which increase risk. With reference to past diet, a possible protective effect was observed for daily consumption of fresh fruit and green vegetables.