Consumption of dairy products and odds of breast cancer: an Iranian case–control study

Background Data on the link between total and individual dairy product consumption and risk of breast cancer are controversial, especially in Middle Eastern populations. Objective This study aimed to evaluate the association between total and individual dairy product consumption and odds of breast cancer among Iranian women. Methods In the context of a population-based case–control study on 350 patients with pathologically confirmed cases of breast cancer and 700 age-matched controls, we assessed dietary intakes using a 106-item semi-quantitative dish-based food frequency questionnaire. Consumption of low- and high-fat dairy products as well as dietary intakes of pasteurized milk, cheese and yogurt were computed. Results Mean (± SD) age and BMI of study participants was 62.4 ± 10.8 y and 24.3 ± 5.2 kg/m 2 , respectively. After controlling for potential covariates, individuals in the top quartile of low-fat dairy product intake were less likely to have breast cancer than those in the bottom quartile (OR 0.08; 95% CI 0.05–0.16), while those with the highest intake of high-fat dairy intake had greater odds for breast cancer than those with the lowest intake (OR 8.62; 95% CI 4.78–15.55). Despite lack of a significant association between yogurt and cheese consumption and odds of breast cancer, we found a positive association between total milk intake (OR 1.76; 95% CI 1.16–2.65) and breast cancer, after controlling for potential confounders. Conclusion Low-fat dairy intake was inversely and high-fat dairy consumption was positively associated with breast cancer. No significant association was found between yogurt and cheese consumption and breast cancer, while total milk intake was associated with a greater odds of breast cancer.