Association between dietary phytochemical index and breast cancer: a case–control study

摘要

Background Dietary intake of isoflavones has been positively associated with risk of breast cancer (BC) in some earlier studies. In addition, most studies on diet–disease associations came from western countries and limited data are available in the Middle-East. Methods This case–control study was performed on 350 women with BC aged over 30?years who were recruited from hospitals or private clinics in Isfahan, Iran. All patients were diagnosed with BC during the maximum of the last 6?months using physical examination and mammography findings. Using cluster method sampling, 700 apparently healthy age- and socioeconomic status-matched controls were randomly selected from healthy women who had no relationship with BC patients and had no familial history of BC. Data on dietary intakes were collected using a validated food-frequency questionnaire. The DPI was calculated based on dietary energy derived from foods rich in phytochemicals (kcal) divided by total daily energy intake (kcal) of each participant. Results Mean?±?SD age and BMI in the study participants were 62.4?±?10.8 years and 24.3?±?5.2?kg/m~(2), respectively. In the crude model, participants in the highest quartile of DPI had 63% lower odds of breast cancer compared to those in the lowest quartile (95% CI 0.26, 0.54; P -trend?