An investigation of soy intake and mammographic characteristics in Hawaii

Abstract

BMI = body mass index; CI = confidence interval; FFQ = food frequency questionnaire; icc = intraclass correlation coefficients; SQ = soy questionnaire; κ w = weighted Kappa statistics. AbstractThis cross-sectional investigation in Hawaii explored the relation between soy foods and mammographic characteristics using two food frequency questionnaires and a computer-assisted density assessment method. Japanese and Chinese women reported significantly greater soy food intake than Caucasian women. Whereas soy intake and the size of the dense areas were not related, soy intake and percent mammographic densities were positively associated. The size of the entire breast and the nondense area (ie the fatty part of the breast) were inversely related to soy intake. These results suggest the hypothesis that soy foods by themselves or as part of an Asian dietary pattern may affect the growth of the female breast before adulthood, but the possible mechanisms of action have to be explored in future studies.Keywords: breast cancer, ethnicity, mammographic densities, nutrition, prevention, soy SynopsisIntroduction: Based on ethnic [1] and international [2] differences in breast cancer risk, and on results from cell and animal studies [3], a role for soy foods in breast cancer prevention has been proposed. The epidemiologic investigations on soy and breast cancer risk have so far produced conflicting results [4][5][6][7][8][9][10]. Mammographic densities that refer to the distribution of fat, connective, and epithelial tissue in the female breast have been shown to be related to breast cancer risk [5]. A high percentage of dense parenchyma on mammographic images appears to confer a fourfold risk of developing breast cancer [11]. Aims: The purpose of this report is to investigate the hypothesis that soy foods are related to lower mammographic densities among a population of women with Caucasian, Chinese, Japanese, and Native Hawaiian ancestry living in Hawaii. Methods: In a cross-sectional study approved by the institutional review boards of all participating institutions, women with different ethnic backgrounds were recruited at five

Associations of Mammographic Density with Dietary Factors in Japanese Women

“…Our results were consistent with those from previous studies (22,23). Soy intake was positively associated with percent density among Caucasian and Native Hawaiian women but not in the Chinese and Japanese women living in Hawaii (22).…”

Soy Protein Containing Isoflavones and Mammographic Density in a Randomized Controlled Trial in Postmenopausal Women

“…In contrast to the findings of randomized trials, most (12,(31)(32)(33) but not all (34) cross-sectional studies show that women with high habitual consumption of soy have lower mammographic density. This might suggest that the duration of the intervention in the trials was too short.…”

Phytoestrogens and breast cancer –promoters or protectors?

“…These data suggest that short-term dietary soy supplementation can induce proliferation in breast tissue of premenopausal women with breast disease. In contrast, soy consumption has been associated with a reduction of mammographic density (Atkinson & Bingham 2002, Jakes et al 2002, whilst Maskarinec & Meng (2001) reported a positive correlation between self-reported soy food intakes and percentage breast density in women living in Hawaii. Increased mammographic density has been associated with a four-to sixfold increased risk of breast cancer (Atkinson et al 1999).…”