(HealthDay News) — Higher intakes of dairy milk are associated with a greater risk for breast cancer, when adjusting for soy intake, according to a study published online Feb. 25 in the International Journal of Epidemiology.
Gary E. Fraser, M.B.Ch.B., Ph.D., from Loma Linda University in California, and colleagues used data from 52,795 North American women (mean age, 57.1 years; 29.7 percent black), initially free of cancer and followed for 7.9 years. Dietary intakes were assessed from food frequency questionnaires.
The researchers found 1,057 new breast cancer cases during follow-up. There were no clear associations found between soy products and breast cancer, independent of dairy. Comparing the 90th to 10th percentiles of dairy intakes, higher intakes of dairy calories and dairy milk were associated with hazard ratios (HRs) of 1.22 and 1.50, respectively. Similar results were seen for full-fat and reduced-fat milks. There were no associations with cheese and yogurt. After substituting median intakes of dairy milk users and soy milk consumers, the HR was 0.68. Associations were similar among premenopausal and postmenopausal cases, as well as in estrogen receptor (ER+, ER−) and progesterone receptor (PR+) cancers.
“Current guidelines for dairy milk consumption could be viewed with some caution,” the authors write.