The association of dietary phytochemical index and breast cancer: a case control study

Introduction & Aim: Nutritional risk factors for breast cancer have been identified in previous studies; whereas the association between phytochemical-rich foods and development of breast cancer has not been thoroughly explored. The objective of this study was to determine association of dietary PI with breast cancer. Methods: This case control study was conducted on the 87 newly diagnosed breast cancer premenopausal women and 198 five-year age matched controls in Tehran, Iran. All cases were considered for inclusion if breast cancer diagnosis occurred less than six month before interview and if no history of other s cancers. Controls were hospital patients who were admitted to the same hospitals as the cases’ for a wide spectrum of diseases such as orthopedic problems, ear/nose/throat diseases or elective surgeries, did not have anyhistory of special diet, cancer, current chronic diseases, undergoing bilateral ovariectomy. All participants signed written, informed consent. Information on usual diet was measured by a validated 168-item semiquantitative food frequency questionnaire that was modified to include Iranian food items among Iranian adults. Dietary PI was calculated as (dietary energy derived from phytochemical-rich foods (kcal)/total daily energy intake (kcal)×100. Demographic information was collected by private face-to-face interviews. Unconditional logistic regression models were used to estimate the strength of association between breast cancer and PI tertiles . Results: The mean age of the cases and controls was 36.5 (SD 7.9) and 36.8 (SD 7.1) years, respectively, and their average BMI was 20.1 (SD 2.9) and 26.3 (SD 3.9) kg/m2, respectively (P value <0.001). Themean dietary PI was 27.1±14.5 in cases and 33.7±15.9 in controls (P<0.001). According to the fully adjusted model, being in the highest tertile of PI index (OR=0.73,95%CI:0.31-0.94) was negatively associated with breast cancer Conclusion: Inverse and dose dependent associations were found between breast cancer and intake of phytochemical-rich foods. Direct antioxidant activity, anti-inflammatory potential and modulation of carbohydrate and lipid metabolism may mediate the beneficial effects of dietary phytochemicals and should be investigated in future studies

کلیدواژه ها:

phytochemical index ، diet ، breast cancer