The association between the dietary inflammatory index (DII) and breast cancer risk; a hospital based case-control study

Abstract

Conclusion: Findings indicated that more pro-inflammatory diet, positively associated to BC risk, particularly among pre-menopausal women, can be regard to potential estrogen-related signaling and inflammation. However, the role of estrogen in association with inflammation can be investigate in future studies. Keywords: Breast cancer; Dietary inflammatory index; Inflammation

Background: Chronic inflammation have been linked to breast cancer (BC) development. Diet through modulation of inflammation can be associated with BC. Dietary inflammatory index (DII) is a newly developed tool to evaluate the inflammatory potential of diet. We evaluated the association between the dietary inflammatory index (DII) and BC risk in a large case-control study in north western of Iran. Methods: For calcilation of DII scores, data were extracted from validated 136-item food frequency questionnaire. Cases were 1007 women with newly diagnosed and histologically confirmed BC, mainly 27-70 years of age, who were recruited from educational hospitals associated with Tabriz University of Medical Sciences and Noornejat private hospital. Controls were 1004 women admitted to the same hospitals and in the parallel timeline for non-neoplasmic disease. Controls were matched with cases for age and study region. For calculation of DII scores, the logistic regression was used to estimate the odds ratios (ORs) and 95% confidence intervals (CIs) for BC risk according to quartiles of DII scores. Results: Multivariate analysis indicated that a higher (DII-excluding supplements; DII-ES) score was associated to higher risk of BC (OR Q4 vs. Q1: 1.67; 95% CI: 1.19-2.35; Ptrend =0.016). Multivariate adjusted model showed that the (DII-including supplements; DII-S) positively associated to BC risk (OR Q4 vs. Q1: 1.42; 95% CI: 1.05-1.93). The increasing trends of DII-ES across strata were associated with elevated risk of BC among premenopausal women (OR Q2 vs. Q1: 1.41; 95% CI: 1.01‒1.97, OR Q3 vs. Q1: 2.11; 95% CI: 1.50‒2.97 and OR Q4 vs. Q1: 1.67; 95% CI: 1.18‒2.36; Ptrend < 0.001). Moreover, the DII-S showed the positive association with BC risk among pre-menopausal women (OR Q3 vs. Q: 1.48; 95% CI: 1.09-2.00, OR Q4 vs. Q1: 1.56; 95% CI: 1.15-2.11; Ptrend=0.019).