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 1088 controls hospitalized for acute nonneoplastic diseases unrelated to tobacco and alcohol consumption. DII scores were computed from a reproducible and valid 78-item food frequency questionnaire.
Results
Logistic regression models controlling for age, sex, study center, education, body mass index, tobacco smoking, alcohol drinking, and nonalcohol energy intake, were used to estimate odds ratios (ORs), and the corresponding 95% confidence intervals (CIs). 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 < 0.0001) for the highest versus the lowest DII quartile. When DII was considered as a continuous variable, the OR was 1.27 (95 % CI 1.15, 1.40) for a one unit (9% of the DII range) increase. Stratified analyses produced slightly stronger associations between DII and laryngeal cancer risk among current smokers (ORQuartile4vs1= 4.16), moderate drinkers (ORQuartile4vs1= 4.86), overweight subjects (ORQuartile4vs1= 3.62), and among those with higher education (ORQuartile4vs1= 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.