Plant foods and risk of laryngeal cancer: a case-control study in Uruguay

In order to examine the relationships between plant foods, defined as the grouping of vegetables, fruits, tubers and legumes, with the risk of developing laryngeal cancer, a case-control study was conducted in Uruguay between 1998-1999, The study included 148 cases with histologically verified squamous cell carcinoma of the larynx, which were frequency matched on age, residence and urban/rural status with 444 hospitalized controls, afflicted by non-neoplastic conditions. Both series of patients were face-to-face interviewed in the hospitals shortly after admittance using a detailed questionnaire. This questionnaire included 62 queries on food items, representative of the usual diet of the Uruguayan population. Food items and food groups were adjusted for tobacco smoking, alcohol drinking and total energy intake. High consumption of plant foods was associated with an OR of 0.42 (95% CI 0.21-0.84). Among subgroups of plant foods, fruits and raw vegetables were associated with a strong reduction in risk (OR for the highest quartile of raw vegetables 0.29, 95% CI 0.15-0.56), Also, legumes were associated with a protective effect (OR 0.62, 95% CI 0.33-1.19). Among individual food items, tomatoes and oranges were associated with the stronger protective effects (OR for tomato intake 0.32, 95% CI 0.17-0.58). The joint effect of heavy smoking and the low intake of vegetables and fruits displayed an increased risk of 19.2 (95% CI 5.7-64.9).