Is dairy intake associated to breast cancer? A case control study of Iranian women.

Current epidemiologic data lack consistent evidence for an association between consumption of dairy products and breast cancer risk. In this study we assessed the relationship between consumption of dairy products and the odds of breast cancer. This case-control study was conducted on 275 women (100 cases and 175 controls). Data regarding sociodemographic factors, medical history, medications, and anthropometric measurements were collected. Dietary data were assessed using a validated food frequency questionnaire. The odds [95% confidence interval (CI)] of breast cancer were estimated across quartile categories of energy-adjusted dairy intake using multiple logistic regression models with adjustment for confounders. We observed that higher consumption of total dairy intake was accompanied with reduced breast cancer risk [odds ratio (OR) = 0.14, 95% CI = 0.04-0.38]. A similar inverse association was also observed for higher intakes of low-fat and fermented dairy products (P for trend <0.05). Lower intake of high-fat dairy was associated with reduced odds of breast cancer, and no significant association was found between nonfermented dairy and breast cancer risk. Our study demonstrates the protective effects of high intakes of total dairy, low-fat and fermented dairy, as well as low intakes of high-fat dairy products against breast cancer risk and shows no association with nonfermented dairy.