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

Abstract

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/m2, 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. © 2021, The Author(s), under exclusive licence to The Japanese Breast Cancer Society.