Nutrient-based dietary patterns and laryngeal cancer: evidence from an exploratory factor analysis

Background: The issue of diet and laryngeal cancer has been rarely addressed considering the potential role of dietary patterns. Methods: We examined this association using data from a case-control study carried out between 1992 and 2000. Cases were 460 histologically confirmed incident laryngeal cancers hospitalized in two Italian areas. Controls were 1,088 subjects hospitalized for acute nonneoplastic diseases unrelated to tobacco or alcohol consumption. Dietary habits were investigated through a 78-item food frequency questionnaire. A posteriori dietary patterns were identified through principal component factor analysis carried out on a selected set of 28 major nutrients. The internal reproducibility, robustness, and reliability of the identified patterns were evaluated. Odds ratios (OR) of laryngeal cancer and 95% confidence intervals (95% CI) were estimated using unconditional multiple logistic regression models on quartiles of factor scores. Results: We identified five major dietary patterns named "animal products," "starch-rich," "vitamins and fiber," "vegetable unsaturated fatty acids," and "animal unsaturated fatty acids." The vitamins and fiber dietary pattern was inversely associated with laryngeal cancer (OR, 0.35; 95% CI, 0.24-0.52 for the highest versus the lowest score quartile), whereas the animal products (OR, 2.34; 95% CI, 1.59-3.45) and the animal unsaturated fatty acids (OR, 2.07; 95% CI, 1.42-3.01) patterns were directly associated with it. There was no significant association between the vegetable unsaturated fatty acids and the starch-rich patterns and laryngeal cancer risk. Conclusion: These findings suggest that diets rich in animal products and animal fats are directly related, and those rich in fruit and vegetables inversely related, to laryngeal cancer risk