Association between Dietary Anthocyanidins and Biliary Cancer Risk in 98,458 Participants: Results from a Prospective Study.

Background: Previous studies have suggested anthocyanidins or anthocyanidin-rich foods and extracts exhibit protective effects against various cancers. However, the relationship between dietary anthocyanidins and the risk of biliary cancer remains uncertain.

Methods: This study used data from the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial to investigate the relationship between total anthocyanidins intake and biliary cancer incidence. Cox regression analysis was conducted to estimate HRs and corresponding 95% confidence intervals (CI) for the incidence of biliary cancer, with adjustments made for confounding factors. A restricted cubic spline model was employed to examine the dose-response relationship. In addition, subgroup and sensitivity analyses were conducted to evaluate potential interactions and test the model's robustness.

Results: During 8.9 years and 872,645.3 person-years of follow-up, 95 cases of biliary cancer were observed. The incidence rate of biliary cancer in this study was 11 cases per 100,000 person-years. Using the fully adjusted Cox regression model, the inverse association was observed between total anthocyanidins intake and the risk of biliary cancer (HR Q4 vs..Q1: 0.52; 95% CI: 0.29-0.91; Ptrend = 0.043). This association remained significant in sensitivity analyses. A linear dose-response relationship (Pnonlinearity = 0.118) and potential interaction with drinking status (Pinteraction = 0.033) were identified.

Conclusions: This study provides evidence of an inverse association between total anthocyanidins intake and biliary cancer incidence.

Impact: Our study found a total anthocyanidin-rich diet was associated with a reduced risk of biliary cancer in Americans ages 55 to 74 years.