Objective: The relationship between diet, including its inflammatory potential, and breast cancer has led to inconsistent results. We investigated the association between a dietary inflammatory index (DII) and the odds of breast cancer in a large case-control study among women.
Methods: This case-control study was carried out on 412 women with pathologically confirmed breast cancer and 456 apparently healthy controls. DII scores were calculated from dietary intake data. Multi-variable adjusted logistic regression was used to obtain odds ratios for breast cancer across quartiles of DII.
Results: A total participants aged 45 ± 10.8 years were included in the present study. After adjustment for potential confounders, individuals in the highest quartile of DII scores had 1.5 times higher odds of breast cancer than those with the lowest (OR= 1.56; 95%CI: 1.04-2.35, Ptrend=0.02). Premenopausal women with the greatest DII had higher odds for breast cancer, compared with those with the lowest DII (OR= 1.92; 95% CI: 1.14-3.25, Ptrend=0.01). No significant association was seen between DII and odds of breast cancer in postmenopausal women.
Conclusion: Dietary inflammatory index might be directly associated with odds of breast cancer particularly in premenopausal women. Prospective cohort studies are needed to confirm these findings.