The Association between Dairy Intake and Breast Cancer in Western and Asian Populations: A Systematic Review and Meta-Analysis

Abstract

PurposeTo date, studies investigating the association between dairy consumption and breast cancer in women have produced conflicting results. As diet is an important, modifiable factor affecting cancer development, the aim of this study was to examine the association between dairy consumption and breast cancer risk.MethodsPubMed, Embase, and Cochrane Library databases were searched with a priority for prospective cohort studies. Case-control studies were also considered in case of the absence of a cohort study.ResultsWe analyzed 22 prospective cohort studies (1,566,940 participants) and five case-control studies (33,372 participants). High and modest dairy consumption (>600 and 400-600 g/day, respectively) significantly reduced the risk of breast cancer compared with low dairy consumption (<400 g/day; risk ratio [RR], 0.90, 95% confidence interval [CI], 0.83-0.98, and RR, 0.94, 95% CI, 0.91-0.98, respectively). A significant linear relationship between dairy consumption and breast cancer risk was found on dose-response analysis. Subgroup analysis found that yogurt (RR, 0.91; 95% CI, 0.83-0.99) and low-fat dairy (RR, 0.85; 95% CI, 0.75-0.96) reduced the risk of breast cancer, while other dairy product types did not. A reduced risk was observed for people in the United States (RR, 0.91; 95% CI, 0.83-0.99) and in those followed for ≥10 years (RR, 0.90; 95% CI, 0.81-0.99). Additionally, the highest level of dairy consumption among Asians was associated with a reduced risk of breast cancer (odds ratio, 0.74; 95% CI, 0.62-0.88).ConclusionDairy consumption was inversely associated with the risk of developing breast cancer and this effect was dependent on the dose, dairy-type, and time.

Milk and dairy products: good or bad for human health? An assessment of the totality of scientific evidence

“…Due to potential bias in the design and the lack of control for known confounders, it is impossible to conclude about the relationship with dairy intake. Also, these findings are in contrast with the additional literature suggesting no or an inverse association between dairy intake and risk of breast cancer (74, 75), ovarian cancer (83, 91), and lung cancer (84, 85). …”

“…In accordance with a meta-analysis from 2011 on prospective cohort studies (74), a recent meta-analysis by Zang et al (75), however, suggested that a high (>600 g/d) and modest (400–600 g/d) dairy intake was associated with a reduced risk of breast cancer (10% and 6%, respectively) compared with a low dairy intake (<400 g/d). Within dairy subgroups, particularly yoghurt and low-fat dairy were found to be inversely associated with the risk of developing breast cancer.…”

Obesity, Dietary Factors, Nutrition, and Breast Cancer Risk

“…Dietary patterns are likely to vary between populations, because of geographic characteristics and cultural differences in food habits, preferences, and availability [125]. Several studies investigating dietary patterns and breast cancer risk have documented an inverse association with a prudent/low fat dietary pattern, which includes the high intake of vegetables, fruits, whole grains, and fish [110, 111, 124, 126], and a positive association with the less healthy Western diet, which is generally characterized by large quantities of red meat, refined grains, potatoes, and fat [127]. …”

Milk Consumption Decreases Risk for Breast Cancer in Korean Women under 50 Years of Age: Results from the Health Examinees Study

“…A case-control study indicated that a diet characterized by a high consumption of milk is associated with a lower risk for breast cancer among both pre-and postmenopausal women in China [33]. Meta-analyses reported that dairy product consumption was inversely associated with the risk for breast cancer, and this effect varied across types of dairy products [20,34,35].…”

“…Several epidemiologic studies have examined the association between consumption of milk and dairy products and the risk for breast cancer [17][18][19]. However, the association between different types of milk and dairy products and risk for breast cancer yield inconsistent results, as only a few studies have shown reduced risks for breast cancer [20][21][22]. Moreover, the findings may vary by the types of dairy products.…”