Long-term anti-inflammatory diet in relation to improved breast cancer prognosis: a prospective cohort study

Abstract

Inflammation-modulating nutrients and inflammatory markers are established cancer risk factors, however, evidence regarding the association between post-diagnosis diet-associated inflammation and breast cancer survival is relatively sparse. We aimed to examine the association between post-diagnosis dietary inflammatory index (DII®) and risks of all-cause and breast cancer-specific mortality. A total of 1064 female breast cancer survivors in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening (PLCO) Trial prospective cohort, were included in this analysis if they had completed the diet history questionnaire (DHQ). Energy-adjusted DII (E-DII^TM) scores were calculated based on food and supplement intake. Cox regression and competing risk models were used to estimate multivariable-adjusted hazards ratios (HRs) and 95% confidence intervals (95% CIs) by E-DII tertile (T) for all-cause and breast cancer-specific mortality. With median follow-up of 14.6 years, there were 296 (27.8%) deaths from all causes and 100 (9.4%) breast cancer-specific death. The E-DII was associated with all-cause mortality (HR T3 vs T1, 1.34; 95% CI, 1.01-1.81; P _trend, 0.049, Table 2) and breast cancer mortality (HR T3 vs T1, 1.47; 95% CI, 0.89-2.43; P _trend, 0.13; multivariable-adjusted HR for 1-unit increment: 1.10; 95% CI: 1.00-1.22). Non-linear positive dose-response associations with mortality from all causes were identified for E-DII scores (P _{non-linearity} < 0.05). The post-diagnosis E-DII was statistically significantly associated with mortality risk among breast cancer survivors. Long-term anti-inflammatory diet might be a means of improving survival of breast cancer survivors.

Keywords: Breast cancer; Risk factors.

Fig. 1. Survival analysis between E-DII scores in T1, T2, and T3.

Kaplan–Meier curves of a overall survival; b breast cancer-specific mortality.

Fig. 2. Non-linear dose–response analysis on E-DII scores and all-causes mortality.

Non-linear dose-response curves for a age and total energy-adjusted and b multivariable-adjusted Cox regression model. The reference level was set at −7.9. A P_{non-linearity} was obtained by testing the null hypothesis that regression coefficient of the second spline was equal to zero. CI confidence interval.

Fig. 3. Food parameter-specific DII score.

The DII score distribution according anti-inflammatory and proinflammatory diets.