Diet diversity and the risk of oral and pharyngeal cancer

Background: Diet diversity has been recommended to achieve a healthy diet and prevent cancer. Aim of the study: The relation between diet diversity (i.e., variety in food intake computed as the total number of foods consumed at least once per week) and the risk of oral and pharyngeal cancer was investigated using data from a multicentric case-control study carried out between 1991 and 2005 in Italy. Methods: Cases were 805 patients with histologically confirmed incident cancers of the oral cavity and pharynx, and controls were 2,081 patients admitted for acute, non-neoplastic diseases, unrelated to tobacco or alcohol consumption. Results: A significant inverse association was observed with total diet diversity. The multivariate odds ratio (OR), adjusted for education, tobacco and alcohol, was 0.78 (95% confidence interval, CI 0.61-0.98) for subjects in the highest tertile of diversity. Inverse relations were found also for diversity within vegetables (OR = 0.62; 95% CI 0.49-0.78) and fruits (OR = 0.67; 95% CI 0.53-0.86). Conclusions: This study suggests that a more diversified, and particularly a diet varied in vegetables and fruit, is a favourable indicator of oral and pharyngeal cancer risk, independently from the major recognised risk factors, i.e. alcohol and tobacco consumption.