Food-Based Dietary Inflammatory Index in Relation to Breast Cancer.

Background: There is no study on the association between food-based dietary inflammatory index (FDII) and odds of breast cancer. This study was conducted to investigate the association between FDII and odds of breast cancer in Iranian women. Methods: In this population-based case-control study, we enrolled 350 pathologically confirmed new cases of breast cancer and 700 controls which were matched with cases in terms of age and socioeconomic status. FDII score was calculated based on participants' dietary intakes. Results: A significant positive association was found between FDII and odds of breast cancer (odds ratio [OR]: 1.38, 95% confidence interval [CI]: 1.01-1.88); such that after taking potential confounders into account, women in the highest tertile of FDII score were 1.52 time more likely to have breast cancer compared with those in the lowest tertile (OR: 1.52, 95% CI: 1.05-2.18). Such a significant positive association was also observed among postmenopausal women, either before (OR: 1.53, 95% CI: 1.09-2.14) or after (OR: 1.54, 95% CI: 1.05-2.27) controlling for covariates. The same association was also observed in normal-weight women, and it remained significant even after controlling for potential confounders (OR: 1.58, 95% CI: 1.04-2.41). Conclusions: We found a significant positive association between FDII and the odds of breast cancer in women, particularly postmenopausal ones.