title: The association between mammographic breast density and bone mineral density in the study of women's health across the nation.
abstract: BACKGROUND
  Bone mineral density and mammographic breast density are each associated with markers of lifetime estrogen exposure. The association between mammographic breast density and bone mineral density in early perimenopausal women is unknown.
  
  
  METHODS
  We analyzed data from a cohort (n = 501) of premenopausal (no change in menstrual regularity) and early perimenopausal (decreased menstrual regularity in past 3 months) participants of African-American, Caucasian, Chinese, and Japanese ethnicity in the Study of Women's Health Across the Nation. Using multivariable linear regression, we examined the cross-sectional association between percent mammographic density and bone mineral density (BMD).
  
  
  RESULTS
  Percent mammographic density was statistically significantly inversely associated with hip BMD and lumbar spine BMD after adjustment (body mass index, ethnicity, age, study site, parity, alcohol intake, cigarette smoking, physical activity, age at first childbirth) in early perimenopausal, but not premenopausal, women. In early perimenopausal women, every 0.1g/cm(2) greater hip BMD predicted a 2% lower percent mammographic density (95% confidence interval -37.0 to -0.6%, p = 0.04).
  
  
  CONCLUSIONS
  Mammographic breast density is inversely associated with BMD in the perimenopausal participants of this community-based cohort. The biological underpinnings of these findings may reflect differential responsiveness of breast and bone mineral density to the steroid milieu.
authors.affiliation: David Geffen School of Medicine at University of California, Los Angeles, CA 90024, USA. ccrandall@mednet.ucla.edu
authors.forename: Carolyn J
authors.initials: CJ
authors.lastname: Crandall
authors.forename: Yan
authors.initials: Y
authors.lastname: Zheng
authors.forename: Arun
authors.initials: A
authors.lastname: Karlamangla
authors.forename: Barbara
authors.initials: B
authors.lastname: Sternfeld
authors.forename: Laurel A
authors.initials: LA
authors.lastname: Habel
authors.forename: Nina
authors.initials: N
authors.lastname: Oestreicher
authors.forename: Janet
authors.initials: J
authors.lastname: Johnston
authors.forename: Jane A
authors.initials: JA
authors.lastname: Cauley
authors.forename: Gail A
authors.initials: GA
authors.lastname: Greendale
mesh_terms: D000273:Adipose Tissue / Q000187:drug effects*; D000328:Adult; D015415:Biomarkers / Q000097:blood; D015992:Body Mass Index; D015519:Bone Density / Q000502:physiology*; D001940:Breast / Q000033:anatomy & histology* / Q000187:drug effects; D001943:Breast Neoplasms / Q000000981:diagnostic imaging / Q000378:metabolism; D003278:Contraceptives, Oral, Hormonal / Q000627:therapeutic use; D015914:Estrogen Replacement Therapy / Q000706:statistics & numerical data; D004967:Estrogens / Q000097:blood* / Q000627:therapeutic use; D005260:Female; D005300:Fertility Agents, Female / Q000627:therapeutic use; D006615:Hip / Q000502:physiology; D006801:Humans; D008137:Longitudinal Studies; D008159:Lumbar Vertebrae / Q000502:physiology; D008327:Mammography; D008875:Middle Aged; D047648:Perimenopause / Q000097:blood / Q000187:drug effects / Q000208:ethnology / Q000502:physiology; D017697:Premenopause / Q000097:blood / Q000187:drug effects / Q000208:ethnology / Q000502:physiology; D012307:Risk Factors; D014481:United States; D016387:Women's Health
chemical_list: D015415:Biomarkers; D003278:Contraceptives, Oral, Hormonal; D004967:Estrogens; D005300:Fertility Agents, Female