title: Mammographic breast density and serum phytoestrogen levels.
abstract: Some forms of estrogen are associated with breast cancer risk as well as with mammographic density (MD), a strong marker of breast cancer risk. Whether phytoestrogen intake affects breast density, however, remains unclear. We evaluated the association between serum levels of phytoestrogens and MD in postmenopausal women. We enrolled 269 women, ages 55-70 yr, who received a screening mammogram and had no history of postmenopausal hormone use. Subjects completed a survey on diet and factors related to MD and provided a blood sample for analysis of 3 phytoestrogens: genistein, daidzein, and coumestrol. We examined whether mean percent MD was related to serum level of phytoestrogens, adjusting for age and body mass index. Genistein and daidzein levels correlated with self-reported soy consumption. Mean percent MD did not differ across women with different phytoestrogen levels. For example, women with nondetectable genistein levels had mean density of 11.0% [95% confidence intervals (CI) = 9.9-12.4], compared to 10.5% (95% CI = 8.0-13.7) and 11.2% (95% CI = 8.7-14.6) for < and ≥ median detectable levels, respectively. In a population with relatively low soy intake, serum phytoestrogens were not associated with mammographic density. Additional studies are needed to determine effects of higher levels, particularly given patterns of increasing phytoestrogen intake.
authors.affiliation: Group Health Research Institute, Seattle, Washington 98101, USA.
authors.forename: Sarah J
authors.initials: SJ
authors.lastname: Lowry
authors.forename: Brian L
authors.initials: BL
authors.lastname: Sprague
authors.forename: Erin J
authors.initials: EJ
authors.lastname: Aiello Bowles
authors.forename: Curtis J
authors.initials: CJ
authors.lastname: Hedman
authors.forename: Jocelyn
authors.initials: J
authors.lastname: Hemming
authors.forename: John M
authors.initials: JM
authors.lastname: Hampton
authors.forename: Elizabeth S
authors.initials: ES
authors.lastname: Burnside
authors.forename: Gale A
authors.initials: GA
authors.lastname: Sisney
authors.forename: Diana S M
authors.initials: DS
authors.lastname: Buist
authors.forename: Amy
authors.initials: A
authors.lastname: Trentham-Dietz
mesh_terms: D000368:Aged; D015992:Body Mass Index; D001943:Breast Neoplasms / Q000000981:diagnostic imaging*; D003375:Coumestrol / Q000097:blood*; D004032:Diet; D005247:Feeding Behavior; D005260:Female; D019833:Genistein / Q000097:blood*; D006801:Humans; D007529:Isoflavones / Q000097:blood*; D008327:Mammography; D008875:Middle Aged; D017698:Postmenopause; D013025:Glycine max
chemical_list: D007529:Isoflavones; C004742:daidzein; D019833:Genistein; D003375:Coumestrol