Citrus Fruit Intake and Breast Cancer Risk: A Quantitative Systematic Review

PURPOSE: We investigated the association between dietary intake of citrus fruits and breast cancer risk. METHODS: The PubMed and EMBASE were searched for relevant articles on diet and breast cancer up to January 2012. All of the epidemiological studies that assessed dietary intake of citrus fruits and presented risk estimates of the association between citrus fruits intake and risk of breast cancer were reviewed. Multivariable-adjusted odds ratios (OR) and associated 95% confidence intervals (CI) for highest versus lowest intake of dietary citrus fruits level were extracted. Overall summary OR was calculated by using a fixed-effect meta-analysis. RESULTS: Six case-control studies out of five articles were eligible. Overall summary OR showed a 10% reduction in risk of breast cancer associated with high intake of citrus fruits (summary OR, 0.90; 95% CI, 0.85-0.96; p<0.001); results were consistent across the studies (I(2)=0). Visual inspection of the results did not suggest a publication bias. CONCLUSION: Pooled results from observational studies showed an inverse association between citrus fruits intake and the risk of breast cancer.