McCann SE; Hays J; Baumgart CW; Weiss EH; Yao S; Ambrosone CB. - - Curr Dev Nutr 2017; 1 (3): e000422

Usual consumption of specific dairy foods is associated with breast cancer in the Roswell Park Cancer Institute Databank and BioRepository

Background. Dairy foods are complex mixtures which include nutrients and non-nutrient substances that could potentially influence cancer etiology, including breast cancer. Objective. The purpose of this study was to examine the associations between the types and quantity of dairy foods consumed and breast cancer among women participating in the Roswell Park Cancer Institute (RPCI) Data Bank and BioRepository (DBBR) between 2003 and 2014. Methods. Archived clinical and questionnaire data were obtained from the DBBR from 1,941 women diagnosed with breast cancer between December 2003 and October 2014, and 1237 control participants. Intakes of dairy foods were queried with a self-administered food frequency questionnaire and grouped into monthly intakes of total dairy, milk, yogurt, low-fat cheese, other cheese, and sweet dairy. Odds ratios (OR) and 95% confidence intervals (CI) were estimated with unconditional logistic regression adjusting for age, race, BMI, menopausal status, energy intake, type of milk usually consumed, cigarette smoking status, and family history of breast cancer. Results. Total dairy intakes were associated with a non-significant 15% reduction in breast cancer risk (p=0.11). Higher intakes of yogurt were associated with reduced risk of breast cancer (OR 0.61, 95% CI 0.46-0.82) and higher intakes of other cheese was associated with a marginally significant increased risk (OR 1.53, 95% CI 0.99-2.34; p=0.05). Associations with dairy foods were mixed when stratified by estrogen receptor status, and in general reflected those of overall breast cancer. However, we observed positive associations between milk intake and risk of ER- breast cancer (OR 1.58, 95% CI 1.05-2.37) and inverse associations between sweet dairy and ER+ breast cancer (OR 0.52, 95% CI 0.29-0.95). Conclusions. Specific dairy foods may contribute to breast cancer risk in women, although risk varies by source of dairy. Future studies are warranted to confirm the protective potential of yogurt in this cancer

Keywords:     cancer cancer epidemiology dietary intake dietary patterns  breast cancer dairy estrogen receptor