title: Insulin-like growth factor-I, IGF-binding protein-3, and mammographic breast density.
abstract: Some studies have suggested that insulin-like growth factor (IGF) pathway is related to premenopausal breast density, one of the strongest known breast cancer risk factors. This study was designed specifically to test the hypothesis that higher levels of IGF-I and lower levels of IGF-binding protein (IGFBP)-3 are associated with high mammographic breast density among premenopausal but not among postmenopausal women. A total of 783 premenopausal and 791 postmenopausal healthy women were recruited during screening mammography examinations. Blood samples were collected at the time of mammography, and plasma IGF-I and IGFBP-3 levels were measured by ELISA. Mammographic breast density was estimated using a computer-assisted method. Spearman's partial correlation coefficients (r(s)) were used to evaluate the associations. Adjusted mean breast density was assessed by joint levels of IGF-I and IGFBP-3 using generalized linear models. Among premenopausal women, high levels of IGF-I and low levels of IGFBP-3 were independently correlated with high breast density (r(s) = 0.083; P = 0.021 and r(s) = -0.124; P = 0.0005, respectively). Correlation of IGF-I with breast density was stronger among women in the lowest tertile of IGFBP-3 than among those in the highest tertile of IGFBP-3 (r(s) = 0.138; P = 0.027 and r(s) = -0.039; P = 0.530, respectively). In contrast, the correlation of IGFBP-3 with breast density was stronger among women in the highest tertile of IGF-I than among those in the lowest tertile of IGF-I (r(s) = -0.150; P = 0.016 and r(s) = -0.008; P = 0.904, respectively). Women in the combined top tertile of IGF-I and bottom tertile of IGFBP-3 had higher mean breast density than those in the combined bottom tertile of IGF-I and top tertile of IGFBP-3 (53.8% versus 40.9%; P = 0.014). No significant association was observed among postmenopausal women. Our findings confirm that IGF-I and IGFBP-3 are associated with breast density among premenopausal women. They provide additional support for the idea that, among premenopausal women, these growth factors may affect breast cancer risk, at least in part, through their influence on breast tissue morphology as reflected on mammogram.
authors.affiliation: Unité de recherche en santé des populations, Centre hospitalier affilié universitaire de Québec, Hôpital Saint-Sacrement, 1050 Chemin Sainte-Foy, Quebec, Quebec, Canada G1S 4L8.
authors.forename: Caroline
authors.initials: C
authors.lastname: Diorio
authors.forename: Michael
authors.initials: M
authors.lastname: Pollak
authors.forename: Celia
authors.initials: C
authors.lastname: Byrne
authors.forename: Benoît
authors.initials: B
authors.lastname: Mâsse
authors.forename: Nicole
authors.initials: N
authors.lastname: Hébert-Croteau
authors.forename: Martin
authors.initials: M
authors.lastname: Yaffe
authors.forename: Gary
authors.initials: G
authors.lastname: Coté
authors.forename: Sylvie
authors.initials: S
authors.lastname: Bérubé
authors.forename: Carol
authors.initials: C
authors.lastname: Morin
authors.forename: Jacques
authors.initials: J
authors.lastname: Brisson
mesh_terms: D000328:Adult; D000368:Aged; D001940:Breast / Q000502:physiology*; D001943:Breast Neoplasms / Q000097:blood* / Q000000981:diagnostic imaging* / Q000453:epidemiology; D003430:Cross-Sectional Studies; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D018970:Insulin-Like Growth Factor Binding Protein 1 / Q000097:blood*; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000097:blood*; D016014:Linear Models; D008327:Mammography; D008875:Middle Aged; D017698:Postmenopause / Q000097:blood; D017697:Premenopause / Q000097:blood; D011856:Radiographic Image Enhancement; D012307:Risk Factors; D011795:Surveys and Questionnaires
chemical_list: D018970:Insulin-Like Growth Factor Binding Protein 1; D018972:Insulin-Like Growth Factor Binding Protein 3