Dietary Approaches to Stop Hypertension (DASH) diets and breast cancer among women: a case control study.

Background: Studying entire dietary patterns is a promising alternative approach to overcome limitations of the single food or nutrient approach. We evaluated the relationship between the scores of 4 established Dietary Approaches to Stop Hypertension (DASH) diet indexes and breast cancer risk among Iranian women.

Methods: This case-control study was carried out on 408 eligible women (136 cases and 272 hospital-based controls). A validated 168 item semi-quantitative food frequency questionnaire was used for assessing usual dietary intakes. DASH index scores were generated based on predefined algorithms for each of the 4 previously described indexes (Dixon's, Mellen's, Fung's and Günther's DASH diet index). Unconditional logistic regression analysis was performed to estimate odds ratio (OR) and 95% confidence intervals (CIs) for score categories or quintiles of DASH diet indexes and breast cancer risk in multivariate adjusted models.

Results: Women in the highest categories of the Mellen's and Günther's scores had lower odds of breast cancer than those in the lowest quintiles (Mellen's OR:0.50; 95% CI:0.62-0.97; P-trend:0.02; Günther's OR:0.48; 95% CI:0.25-0.93; P-trend:0.05). However, no significant associations were found between Dixon's and Fung's DASH score and breast cancer risk. Modification by menopausal status revealed that breast cancer risk was only reduced in postmenopausal women with higher scores on Mellen's index (OR:0.24; 95% CI:0.08-0.68; P-trend:0.04).

Conclusion: A greater adherence to 2 of the 4 DASH indexes (Mellen's and Günther's indexes) was associated with decreased risk of breast cancer.