title: Relationships between circulating hormone levels, mammographic percent density and breast cancer risk factors in postmenopausal women.
abstract: BACKGROUND
  Endogenous hormones and insulin-like growth factors (IGF) play a central role in breast cancer development. Mammographic density, an important breast cancer risk factor, has been associated with these biomarkers in premenopausal women. The aim of this study was to assess the relationships between circulating hormones, clinical features related to breast cancer risk and mammographic density in postmenopausal women.
  
  
  METHODS
  The study included 226 postmenopausal women participating in a clinical prevention trial. We performed baseline measurements of mammographic percent density and circulating levels of estradiol, sex-hormone binding globulin (SHBG), follicle stimulating hormone (FSH), prolactin, C-terminal cross-link telopeptide, IGF-I, and IGF binding protein-3.
  
  
  RESULTS
  Median age and time since last menses were 52 years and 15 months, respectively. Median body mass index was 24.1 kg/m(2). After adjusting for age and body mass index, estradiol was the only biomarker significantly correlated with mammographic density (r = 0.17; P = 0.04). Women with normal body mass index had higher mammographic density (P < 0.001), higher SHBG (P < 0.0001), higher FSH (P = 0.002) and lower estradiol levels (P = 0.01) than those who were overweight. Women who had previous biopsies for benign breast disease had a higher mammographic density (P = 0.006).
  
  
  CONCLUSIONS
  In these recently postmenopausal women, mammographic percent density is directly associated with circulating estradiol levels. Our results provide further support to the role of circulating hormones in breast cancer risk.
authors.affiliation: Division of Cancer Prevention and Genetics, European Institute of Oncology, Milan, Italy.
authors.forename: Harriet
authors.initials: H
authors.lastname: Johansson
authors.forename: Sara
authors.initials: S
authors.lastname: Gandini
authors.forename: Bernardo
authors.initials: B
authors.lastname: Bonanni
authors.forename: Frederique
authors.initials: F
authors.lastname: Mariette
authors.forename: Aliana
authors.initials: A
authors.lastname: Guerrieri-Gonzaga
authors.forename: Davide
authors.initials: D
authors.lastname: Serrano
authors.forename: Enrico
authors.initials: E
authors.lastname: Cassano
authors.forename: Francesca
authors.initials: F
authors.lastname: Ramazzotto
authors.forename: Laura
authors.initials: L
authors.lastname: Baglietto
authors.forename: Maria Teresa
authors.initials: MT
authors.lastname: Sandri
authors.forename: Andrea
authors.initials: A
authors.lastname: Decensi
mesh_terms: D015992:Body Mass Index; D001943:Breast Neoplasms / Q000097:blood* / Q000473:pathology*; D004797:Enzyme-Linked Immunosorbent Assay; D004958:Estradiol / Q000097:blood; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood; D006801:Humans; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000097:blood; D007334:Insulin-Like Growth Factor I / Q000032:analysis; D008327:Mammography; D008875:Middle Aged; D017698:Postmenopause / Q000097:blood*; D011388:Prolactin / Q000097:blood; D012307:Risk Factors; D012738:Sex Hormone-Binding Globulin / Q000032:analysis
chemical_list: D018972:Insulin-Like Growth Factor Binding Protein 3; D012738:Sex Hormone-Binding Globulin; D004958:Estradiol; D007334:Insulin-Like Growth Factor I; D011388:Prolactin; D005640:Follicle Stimulating Hormone