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

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.