Dietary inflammatory index and incidence of and death from primary liver cancer: A prospective study of 103,902 American adults

Chronic inflammation plays an important role in primary liver cancer (PLC) etiology and can be influenced by dietary habits. No prospective study has investigated the association of dietary inflammatory index (DII) with PLC incidence and mortality. Therefore, we used prospective data from the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial to fill this gap. The DII was calculated from a validated 137‐item food frequency questionnaire in a cohort of 103,902 individuals. Cox regression was used to estimate hazard ratios (HRs) for PLC incidence, and competing risk regression was used to estimate subdistribution HRs (SHRs) for PLC mortality. Restricted cubic spline regression was employed to identify the potential dose–response pattern. A total of 120 PLC cases and 102 PLC deaths were observed during follow‐up. Higher DII scores from food and supplement were found to be associated with higher risks of developing PLC (HR Tertile 3 vs. 1 2.05; 95% confidence interval [CI] 1.23–3.41) and death from this disease (SHR Tertile 3 vs. 1 1.97; 95% CI 1.13–3.41). Similar results were obtained for DII score from food only. A nonlinear dose–response pattern was identified for the aforementioned associations (all p nonlinearity < 0.05). Overall, a more pro‐inflammatory diet, as suggested by higher DII scores, is associated with higher risks of PLC incidence and mortality. These findings indicate that encouraging intake of more anti‐inflammatory dietary components and reducing intake of pro‐inflammatory components represent an attractive strategy to reduce PLC incidence and mortality.