We would like to correct an inaccurate summary of our previous findings (1) on the relationship between self-reported soy intake and mammographic densities. In a recent study by Jakes et al. (2), our findings are described as follows: “Women with higher soy intake had lower percentage mammographic densities when compared with women with lower soy intake.” Our findings and conclusions were, in fact, the opposite.
Contrary to our hypothesis, we found a significant positive association between self-reported soy intake and percentage of densities (Ptrend = 0.04). Although it is worth noting that our findings differed by ethnic group and the Chinese/Japanese group had a nonsignificant trend in the opposite direction from the total study population, our results were nonetheless clearly mischaracterized.
We would also like to note three additional questions about the Jakes et al. study (2): (a) making inferences from our findings in support of theirs may be significantly complicated by the differences in mammographic measures used (the Tabar classification in their case, a quantitative method in ours); (b) the quartile boundary values for the main independent variable, soy consumption, are not given, and the raw mean is not given for any of the dietary variables; this leaves the range of intake values at which one might expect protective effects unclear; and (c) the finding that increased fat consumption still provided a protective effect even after adjusting for BMI,1 and energy intake is puzzling. Although the discussion addresses the inverse relation of BMI and energy intake with mammographic density, it implies that adjusting for BMI and energy intake should remove the confounding effects that make fat consumption appear to have a protective effect. Their results suggest the contrary view, and no explanation is offered for the continued protective effect of fat consumption after adjustment.
The abbreviation used is: BMI, body mass index.
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