Proinflammatory Dietary Pattern and Risk of Total and Subtypes of Breast Cancer Among U.S. Women

Abstract

Background Dietary patterns promoting chronic inflammation, including the empirical dietary inflammatory pattern (EDIP), have been associated with certain cancers. Investigating whether this dietary pattern is associated with breast cancer—where the role of inflammation is less well-defined—could provide valuable insights and potentially improve strategies for preventing this cancer. Methods We prospectively followed 76,386 women from Nurses’ Health Study (NHS, 1984-2018) and 92,886 women from Nurses’ Health Study II (NHSII, 1991-2019). Diet was assessed by food frequency questionnaires (FFQs) every 4 years, starting at baseline. The inflammatory potential of diet was evaluated using the validated EDIP based on plasma CRP, IL-6, and TNFα-R2. Higher scores indicate higher dietary inflammatory potential. Hazard ratios and 95%CIs of overall and subtypes of breast cancer were estimated using multivariable-adjusted Cox regression models. Results During 4,490,842 person-years of follow-up, we documented 11,026 breast cancer cases. Women in the highest, compared with the lowest, EDIP quintile were at higher breast cancer risk (HRQ5vs.Q1=1.12; 95% CI, 1.05, 1.19; P-trend<0.001). The association was stronger for ER-negative tumors (HRQ5vs.Q1=1.29; 95% CI, 1.09, 1.53; P-trend=0.003). Also, we observed that the association of EDIP with breast cancer risk differed by molecular subtype, with the strongest association observed with basal-like tumors (HRQ5vs.Q1=1.80; 95% CI, 1.20, 2.71; P-trend=0.004). Conclusions Higher EDIP scores were associated with a modestly increased risk of breast cancer, which was more pronounced for ER-negative and basal-like breast tumors. These results support the hypothesis that diet-related inflammation plays a role in breast cancer etiology, particularly tumors lacking hormone receptors.