Risk factors for stomach cancer in Brazil (I): a case-control study among non-Japanese Brazilians in Sao Paulo

Background: Stomach cancer is an important health problem in Brazil, with an estimated 20 000 new cases per year and it was the most frequent cancer site in men and the third most frequent site in women in Sao Paulo in 1993. Nevertheless, there are no reports of analytical epidemiological study on stomach cancer in Brazil. Methods: A hospital-based case-control study was conducted among Brazilian residents with a non-Japanese background in the city; 236 consecutive cases of histologically confirmed stomach cancer were matched to the same number of controls admitted for non-neoplastic diseases by age (+/- 5 years) and gender. The socio-demographic characteristics, personal and family medical history, lifetime history of tobacco use and dietary habits were determined by interview using a structured questionnaire. Results: Non-white race, lower educational background and lower family income were more frequent in stomach cancer patients. After adjustment for race and educational background, cigarette smoking, frequent use of oil and frequent consumption of egg were significantly associated with increased risk of stomach cancer, while frequent consumption of fruit and vegetables decreased the risk. These associations did not change substantially after mutual adjustment of the other variables. Conclusions: The present study confirmed that low socio-economic status, cigarette smoking and low consumption of fruit and vegetables were risk factors of stomach cancer in Sao Paulo, Brazil.