title: Associations between soy, diet, reproductive factors, and mammographic density in Singapore Chinese women.
abstract: Although the evidence is not completely consistent, soy intake has been inversely associated with breast cancer risk, and the strongest results have been observed in certain Asian populations. To address this issue and to examine the association between mammographic density and reproductive factors in this population, we conducted a cross-sectional analysis of mammograms and validated food-frequency questionnaires from 380 Chinese women living in Singapore. Percent mammographic density, a biomarker for breast cancer risk, was assessed using a validated computer-assisted method. We used generalized linear models to estimate mean mammographic density by quartiles of soy intake and intake of other dietary factors while adjusting for potential confounders. Percent mammographic density was inversely associated with age, body mass index, parity, breastfeeding, and soy intake. The difference in mammographic density between the highest and lowest quartiles of soy intake was 4-5%; this difference was statistically significant for soy protein and soy isoflavone intake and is similar in magnitude to what has been reported in Western populations when women undergo menopause or commence hormone therapy. We found no evidence that high fiber, fruit, or vegetable intake has protective effects on mammographic density. Our results suggest that the effect of soy intake on percent mammographic density is moderate but possibly of clinical relevance.
authors.affiliation: University of Southern California, Los Angeles, CA 90089, USA. gursin@usc.edu
authors.forename: Giske
authors.initials: G
authors.lastname: Ursin
authors.forename: Can-Lan
authors.initials: CL
authors.lastname: Sun
authors.forename: Woon-Puay
authors.initials: WP
authors.lastname: Koh
authors.forename: Kei-Siong
authors.initials: KS
authors.lastname: Khoo
authors.forename: Fei
authors.initials: F
authors.lastname: Gao
authors.forename: Anna H
authors.initials: AH
authors.lastname: Wu
authors.forename: Mimi C
authors.initials: MC
authors.lastname: Yu
mesh_terms: D000367:Age Factors; D000368:Aged; D000704:Analysis of Variance; D015992:Body Mass Index; D001942:Breast Feeding / Q000453:epidemiology; D001943:Breast Neoplasms / Q000453:epidemiology* / Q000208:ethnology* / Q000517:prevention & control; D002681:China / Q000208:ethnology; D003430:Cross-Sectional Studies; D004032:Diet; D004034:Diet Surveys; D005260:Female; D006801:Humans; D007529:Isoflavones / Q000008:administration & dosage; D008327:Mammography / Q000379:methods*; D008875:Middle Aged; D010298:Parity; D011247:Pregnancy; D012098:Reproduction; D012307:Risk Factors; D012846:Singapore / Q000453:epidemiology; D045730:Soy Foods; D011795:Surveys and Questionnaires
chemical_list: D007529:Isoflavones