Association of Dietary Quality Indices and Glioma: A Case-Control Study

Background and Objectives: Glioma is the most common primary brain tumor, which mostly occurs in adults and is associated with high mortality. The purpose of this study was to investigate the association of food quality indices and glioma in Iranian adults.   Methods: This case-control study was performed on 128 patients with glioma and 256 healthy individuals (matched for age and gender) in hospitals affiliated to Shahid Beheshti University of Medical Sciences, Tehran, between 2009 and 2011. Dietary assessment was performed using a validated block-format 123-item semi-quantitative food frequency questionnaire. Dietary Indices (DDS, AHEI-2010) were developed based on standard methods. Data were analyzed by independent t-test, Chi-Square and ANOVA.   Results: In this study, after controlling for potential confounders, a significant inverse association was found between DDS and risk of glioma (OR: 0.39, 95% CI: 0.17-0.89). This finding was also seen when further adjustment was made for BMI; so that participants in the highest quartile of DDS, were 59% less likely to have glioma compared to those in the lowest quartile (OR: 0.41, 95% CI: 0.18 - 0.93). In addition, a significant inverse association was found between adherence to AHEI and glioma; such that in the fully adjusted model, the participants in the fourth quartile of AHEI had 62% lower risk of glioma compared to those in the the first quartile (OR: 0.38, 95% CI: 0.17-0.84).   Conclusion: The results of this study showed that following a high-diversity healthy diet is associated with reduction in the risk of glioma.