"Cancer mortality statistics in 33 countries of the world were compiled and calculated from data edited from a magnetic tape copy of the World Health Organization (WHO) data base of cancer mortality." (1.)
Using this, I checked for correlations between female breast cancer mortality rates in the 30 countries for which data was available, and food and environmental factors collected from various other sources (2, 3, 4).
The highest correlation (R=.79, p much less than .01) was between breast cancer and animal source Calorie consumption (see graph below).
There was a lower but still significant correlation between breast cancer mortality and milk production (R=.55, p=.001). This would support the hypothesis (5.) that estrogens and insulin-like growth factor (IGF-I) in cow's milk stimulate breast cancer. (see graph below)
Multiple regression analysis showed some additional correlations. A large correlation coefficient (R) and a p value less than .05 suggests that there is a significant statistical relationship between the dietary factor and the disease, although it does not prove that the one causes the other. Negative R values indicate an inverse relationship (e.g. the more vegetable source protein consumption, the lower the incidence of breast cancer).
William Harris, M.D.
(1.) Tominaga S., Aoki K, Fujimoto I, Kurihara M. Cancer Mortality and
Morbidity Statistics, Japan and the World-1994.
(2.)Food and Agriculture Organization of the United Nations. FAO Production Yearbook. Rome, 1987.
(3.) Kurian, George Thomas. The Book of World Rankings. Facts on File
Inc.119 West 57th St. New York, N.Y. 10019.
(4.) Kurian, George Thomas. The New Book of World Rankings. Facts on
File Inc.460 Park Ave. So. New York, N.Y.
(5.) Dairy products and breast cancer: the IGF-I, estrogen, and bGH
hypothesis. Outwater JL; Nicholson A; Barnard N. Med
(6.) BMDP Statistical Software. BMDP New System for Windows. Los Angeles, 1994. ISBN 0-935386-30-0.