Padrões dietéticos e risco de câncer oral: estudo caso-controle em São Paulo

OBJECTIVE: To analyze the association between dietary patterns and oral cancer. METHODS: The study, part of a Latin American multicenter hospital-based case-control study, was conducted in São Paulo, Southeastern Brazil, between November 1998 and March 2002 and included 366 incident cases of oral cancer and 469 controls, frequency-matched with cases by sex and age. Dietary data were collected using a food frequency questionnaire. The risk associated with the intake of food groups defined a posteriori, through factor analysis (called factors), was assessed. The first factor, labeled prudent, was characterized by the intake of vegetables, fruit, cheese, and poultry. The second factor, traditional, consisted of the intake of rice, pasta, pulses, and meat. The third factor, snacks, was characterized as the intake of bread, butter, salami, cheese, cakes, and desserts. The fourth, monotonous, was inversely associated with the intake of fruit, vegetables and most other food items. Factor scores for each component retained were calculated for cases and controls. After categorization of factor scores into tertiles according to the distribution of controls, odds ratios and 95% confidence intervals were calculated using unconditional multiple logistic regression. RESULTS: Traditional factor showed an inverse association with cancer (OR=0.51; 95% CI: 0.32; 0.81, p-value for trend 0.14), whereas monotonous was positively associated with the outcome (OR=1.78; 95% CI: 1.78; 2.85, p-value for trend <0.001). CONCLUSIONS: The study data suggest that the traditional Brazilian diet, consisting of rice and beans plus moderate amounts of meat, may confer protection against oral cancer, independently of any other risk factors such as alcohol intake and smoking.OBJETIVO: Analisar padrões dietéticos relacionados com o câncer oral. MÉTODOS: Estudo caso-controle de base hospitalar, parte de um estudo multicêntrico na América Latina, foi realizado em São Paulo entre novembro de 1998 e março de 2003 em 366 casos incidentes de câncer oral e 469 controles, pareados por freqüência de sexo e idade. O inquérito dietético foi realizado por questionário de freqüência alimentar. Analisou-se o risco associado ao consumo de grupos de alimentos definidos a posteriori, por análise fatorial. O primeiro fator, denominado prudente, caracterizou-se pelo consumo de vegetais, frutas, queijos e aves. O segundo, tradicional, pelo consumo de arroz e massas, leguminosas e carne, enquanto o terceiro, lanches, pelo consumo de pão, manteiga, embutidos, queijos e doces. O último, monótono, associou-se inversamente ao consumo de frutas e vegetais, e a maior parte dos outros itens alimentares. Calculou-se um escore para cada padrão derivado, para casos e controles. Após categorização dos escores em tercis, de acordo com a distribuição dos controles, estimou-se a odds ratio e o intervalo de confiança de 95% por regressão logística múltipla não condicional. RESULTADOS: O padrão tradicional relacionou-se inversamente com o câncer oral (OR=0,51; IC 95%: 0,32; 0.81, p=0,140), enquanto o padrão monótono associou-se positivamente (OR=1,78; IC 95%: 1,78; 2,85, p