OBJECTIVE

Breast cancer is the most common cancer among women worldwide. Most previous studies focused on individual nutrients or foods rather than overall dietary patterns. We aimed to assess the association between major dietary patterns and breast cancer risk.

METHODS

In a hospital-based case-control study, 134 women diagnosed as breast cancer and 267 controls were recruited from referral hospitals in Tehran, Iran. Dietary intakes were evaluated by using a validated 168-item food frequency questionnaire. Dietary pattern were identified by factor analysis. Odds ratios (OR) were estimated using logistic regression.

RESULTS

Two dietary patterns were extracted: healthy and unhealthy. The "Healthy" dietary pattern was loaded for high consumptions of fruits, vegetables, seeds, legume, fish and sea foods, whole grains, liquid oils, olive oils and olive and lack of salt intake. "Unhealthy" dietary pattern was characterized by high factor loadings for sweets, soft drinks, mayonnaise, solid oils, processed meat, fried and boiled potato and salt intake. In multivariate logistic regression analyses, the healthy dietary pattern was not associated with breast cancer risk (OR: 0.83; 95%CI: 0.36, 1.89; P-trend = 0.50), while women in the highest quartile of the unhealthy dietary pattern had a significantly increased breast cancer risk (OR: 2.21; 95%CI: 1.04, 4.690; P-trend = 0.009). When stratified by menopausal status, unhealthy dietary pattern showed inverse association with breast cancer risk only among post-menopausal women (OR: 3.56; 95%CI: 1.16, 10.95; P-trend = 0.008).

CONCLUSIONS

Our findings showed that an unhealthy dietary pattern might be associated with higher risk of breast among Iranian women.