Higher dietary phytochemical index is associated with lower risk of epithelial ovarian cancer in Chinese women: a case–control study

Abstract

Background Dietary phytochemicals have been suggested to play a protective role against cancer development. This study aimed to examine the association between dietary phytochemical index (DPI) and epithelial ovarian cancer (EOC) risk among Chinese women. Methods In this retrospective case–control study, 500 women (250 newly diagnosed EOC patients and 250 cancer-free participants) were included. Dietary intake was assessed using a validated food frequency questionnaire (FFQ), and DPI was calculated as the percentage of energy derived from phytochemical-rich foods. Multivariable logistic regression models were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for the association between DPI and EOC risk. Results Higher DPI was significantly associated with lower odds of EOC. Each one-unit increase in DPI was linked to a reduced risk in both crude and adjusted models (fully adjusted OR: 0.90; 95% CI: 0.81–0.99). Participants in the highest DPI tertile had a 31% lower odds of EOC compared to those in the lowest tertile (OR: 0.69; 95% CI: 0.49–0.96). The inverse association was more pronounced among overweight/obese women (P for interaction = 0.041). Conclusion Greater adherence to a phytochemical-rich diet may be associated with reduced risk of EOC. Prospective studies are warranted to confirm these findings.