Letters Section Editor: Robert M. Golub, MD, Senior Editor.
To the Editor: The Women's Health Initiative (WHI) randomized controlled trial of a low-fat dietary pattern by Dr Prentice and colleagues1 found a reduced risk of invasive breast cancer that did not quite reach statistical significance. An important issue is not whether the results are significant but whether any reduction in risk should be attributed to lower fat intake or to the reduction of body weight observed in the intervention group and generated by lower energy intake in that group. As seen in Table 2 of the article, over a 6-year period the average body weight reduction was more pronounced in the intervention group than in the comparison group by 1.4 kg (the mean value of the differences in weight changes of 2.2, 1.3, and 0.8 kg at years 1, 3, and 6, respectively).
Lagiou P, Trichopoulos D, Adami H. Low-Fat Diet and Risk of Breast Cancer. JAMA. 2006;296(3):278-279. doi:10.1001/jama.296.3.278-a