Bahareh Sasanfar - Department of Nutrition, School of Public Health, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
Fatemeh Toorang - Department of Community Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences, Tehran, Iran.
Saeed Nemati - Cancer Research Center, Cancer Institute of Iran, Tehran University of Medical Sciences, Tehran, Iran
Elham Mohebbi - Cancer Research Center, Cancer Institute of Iran, Tehran University of Medical Sciences, Tehran, Iran
Leila Azadbakht - Diabetes Research Center, Endocrinology and Metabolism Clinical Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran.
Kazem Zendehdel - Cancer Biology Research Center, Cancer Institute of Iran, Tehran University of Medical Sciences, Tehran, Iran.

Background: Most of previous studies have investigated the association of specific food or nutrient with risk of breast cancer (BC) rather than overall diet and there is lack of evidence regarding dietary pattern in BC development. This study aims to examine the association between dietary patterns and risk of BC among Iranian women. Methods: This case–control study was carried out on ۴۵۳ BC women and ۴۹۶ healthy controls. A reliable and valid FFQ was used to evaluate usual dietary intake. Factor analysis was also applied to address the most major dietary patterns which were known as the healthy and unhealthy dietary patterns. Results: Those in the highest quartile of healthy dietary pattern had lower risk of BC (P = ۰.۰۰۱). However, being in the highest quartile of unhealthy pattern was associated with ۲.۰۴-fold increase of BC risk (P = ۰.۰۰۴) compared to the lowest quartile. In premenopausal women, risk of BC in upper quartile of healthy pattern was lower than the lowest quartile (OR = ۰.۴۷; CI = ۰.۲۶ – ۰.۸۳, P = ۰.۰۰۴). More adherence to the unhealthy dietary pattern was associated with higher risk of BC (OR = ۲.۸۵; ۹۵% CI = ۱.۵۷- ۵.۱۷, P < ۰.۰۰۰۱).  No significant association was observed between the healthy or unhealthy dietary patterns among postmenopausal women. Conclusion: The findings indicated that the healthy dietary pattern could be considered as a protective factor in terms of BC in women and particularly among premenopausal women.

Dietary pattern, Breast neoplasms, Factor analysis, Case-control