title: IGF-I and mammographic density in four geographic locations: a pooled analysis.
abstract: Insulin-like growth factor (IGF-I) and prolactin have been found to be associated with breast cancer risk and with mammographic density. In a pooled analysis from 4 geographic locations, we investigated the association of percent mammographic density with serum levels of IGF-I, IGFBP-3 and prolactin. The pooled data set included 1,327 pre- and postmenopausal women: Caucasians from Norway, Arizona and Hawaii, Japanese from Hawaii and Japan, Latina from Arizona, and Native Hawaiians from Hawaii. Serum samples were assayed for IGF-I, IGFBP-3 and prolactin levels using ELISA assays. Mammographic density was quantified using a computer-assisted density method. After stratification by menopausal status, multiple regression models estimated the relation between serum analytes and breast density. All serum analytes except prolactin among postmenopausal women differed significantly by location/ethnicity group. Among premenopausal subjects, IGF-I levels and the molar ratio were highest in Hawaii, intermediate in Japan and lowest in Arizona. For IGFBP-3, the order was reversed. Among postmenopausal subjects, Norwegian women had the highest IGF-I levels and women in Arizona had the lowest while women in Japan and Hawaii had intermediate levels. We observed no significant relation between percent density and IGF-I or prolactin levels among pre-and postmenopausal women. The significant differences in IGF-I levels by location but not ethnicity suggest that environmental factors influence IGF-I levels, whereas percent breast density varies more according to ethnic background than by location. Based on this analysis, the influence of circulating levels of IGF-I, IGFBP-3, and prolactin on percent density appears to be very small.
authors.affiliation: Cancer Research Center, University of Hawaii, Honolulu, HI 96813, USA. gertraud@crch.hawaii.edu
authors.forename: Gertraud
authors.initials: G
authors.lastname: Maskarinec
authors.forename: Yumie
authors.initials: Y
authors.lastname: Takata
authors.forename: Zhao
authors.initials: Z
authors.lastname: Chen
authors.forename: Inger Torhild
authors.initials: IT
authors.lastname: Gram
authors.forename: Chisato
authors.initials: C
authors.lastname: Nagata
authors.forename: Ian
authors.initials: I
authors.lastname: Pagano
authors.forename: Kentaro
authors.initials: K
authors.lastname: Hayashi
authors.forename: Leslie
authors.initials: L
authors.lastname: Arendell
authors.forename: Guri
authors.initials: G
authors.lastname: Skeie
authors.forename: Sabina
authors.initials: S
authors.lastname: Rinaldi
authors.forename: Rudolph
authors.initials: R
authors.lastname: Kaaks
mesh_terms: D001130:Arizona / Q000208:ethnology; D044466:Asian People; D015992:Body Mass Index; D001940:Breast / Q000473:pathology*; D004797:Enzyme-Linked Immunosorbent Assay; D005006:Ethnicity; D005260:Female; D006254:Hawaii / Q000208:ethnology; D006630:Hispanic or Latino; D006801:Humans; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000097:blood*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D007564:Japan / Q000208:ethnology; D008327:Mammography; D008875:Middle Aged; D009664:Norway / Q000208:ethnology; D017698:Postmenopause; D017697:Premenopause; D011388:Prolactin / Q000097:blood*; D044465:White People
chemical_list: D018972:Insulin-Like Growth Factor Binding Protein 3; D007334:Insulin-Like Growth Factor I; D011388:Prolactin