title: Mammographic density in a multiethnic cohort.
abstract: OBJECTIVE
  To compare mammographic density among premenopausal and early perimenopausal women from four racial/ethnic groups and to examine density and acculturation among Japanese and Chinese women.
  
  
  METHODS
  The study included 391 white, 60 African American, 171 Japanese, and 179 Chinese participants in the Study of Women's Health Across the Nation, a multisite study of US women transitioning through menopause. Mammograms done when women were premenopausal or early perimenopausal were assessed for area of dense breast tissue and the percent of the breast occupied by dense tissue (percent density). Information on race/ethnicity, acculturation, and other factors was obtained from standardized instruments. Multiple linear regression modeling was used to examine the association between race/ethnicity or acculturation and density measures.
  
  
  RESULTS
  Age-adjusted mean percent density was highest for Chinese (52%) and lowest for African American (34%) women. After additional adjustment for body mass index, menopause status, age at first birth, breast-feeding duration, waist circumference, and smoking, African Americans had the highest mean percent density (51%) and Japanese women had the lowest (39%). In contrast, the area of dense tissue was highest for African Americans and similar for white, Japanese, and Chinese women. Less acculturated Chinese and Japanese women tended to have a larger area of density and a higher percent density.
  
  
  CONCLUSIONS
  Neither the age-adjusted nor fully adjusted results for percent density or area of dense tissue reflected current differences in breast cancer incidence rates among similarly aged African American, Japanese, Chinese, and white women. In addition, mammographic density was higher in less acculturated Asian women.
authors.affiliation: Division of Research, Kaiser Permanente, Oakland, CA 94612, USA. Laurel.Habel@kp.org
authors.forename: Laurel A
authors.initials: LA
authors.lastname: Habel
authors.forename: Angela M
authors.initials: AM
authors.lastname: Capra
authors.forename: Nina
authors.initials: N
authors.lastname: Oestreicher
authors.forename: Gail A
authors.initials: GA
authors.lastname: Greendale
authors.forename: Jane A
authors.initials: JA
authors.lastname: Cauley
authors.forename: Joyce
authors.initials: J
authors.lastname: Bromberger
authors.forename: Carolyn J
authors.initials: CJ
authors.lastname: Crandall
authors.forename: Ellen B
authors.initials: EB
authors.lastname: Gold
authors.forename: Francesmary
authors.initials: F
authors.lastname: Modugno
authors.forename: Martine
authors.initials: M
authors.lastname: Salane
authors.forename: Charles
authors.initials: C
authors.lastname: Quesenberry
authors.forename: Barbara
authors.initials: B
authors.lastname: Sternfeld
mesh_terms: D000328:Adult; D017677:Age Distribution; D044466:Asian People / Q000706:statistics & numerical data; D044383:Black People / Q000706:statistics & numerical data; D001824:Body Constitution / Q000208:ethnology*; D015992:Body Mass Index; D001941:Breast Diseases / Q000000981:diagnostic imaging* / Q000208:ethnology*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008327:Mammography / Q000706:statistics & numerical data; D008875:Middle Aged; D044465:White People / Q000706:statistics & numerical data; D016387:Women's Health / Q000208:ethnology*; D001741:Black or African American