Inflammatory potential of diet and risk of laryngeal cancer in a case–control study from Italy

Background: Besides tobacco and alcohol, diet and inflammation have been suggested to be important risk factors for laryngeal cancer. In this study, we examined the role of diet-associated inflammation, as estimated by dietary inflammatory index (DII) scores, in laryngeal cancer in a multicentre case–control study conducted between 1992 and 2000 in Italy. Methods: This study included 460 cases with incident, histologically confirmed laryngeal cancer, and 1,088 controls hospitalized for acute non-neoplastic diseases unrelated to tobacco and alcohol consumption. DII scores were computed from a reproducible and valid 78-item food-frequency questionnaire. Logistic regression models controlling for age, sex, study center, education, body mass index, tobacco smoking, alcohol drinking, and non-alcohol energy intake were used to estimate odds ratios (ORs) and the corresponding 95 % confidence intervals (CIs). Results: Subjects with higher DII scores (i.e., with a more pro-inflammatory diet) had a higher risk of laryngeal cancer. The OR was 3.30 (95 % CI 2.06, 5.28; p for trend quartile4vs1 = 4.68), overweight subjects (OR_Quartile4vs1 = 3.62), and among those with higher education (OR_Quartile4vs1 = 3.92). We also observed a strong combined effect of higher DII and tobacco smoking or alcohol consumption on risk of laryngeal cancer. Compared with non-smokers having low DII scores, the OR was 6.64 for smokers with high DII scores. Likewise, compared with non/moderate drinkers with low DII, the OR was 5.82 for heavy drinkers with high DII. Conclusion: These results indicate that a pro-inflammatory diet is associated with increased risk of laryngeal cancer.