title: Body fatness during childhood and adolescence and breast density in young women: a prospective analysis.
abstract: BACKGROUND
  Overweight and obesity in childhood and adolescence are associated with reduced breast cancer risk, independent of adult body mass index (BMI). These associations may be mediated through breast density.
  
  
  METHODS
  We prospectively examined associations of early life body fatness with adult breast density measured by MRI in 182 women in the Dietary Intervention Study in Children (DISC) who were ages 25-29 at follow-up. Height, weight, and other factors were measured at baseline (ages 8-10) and annual clinic visits through adolescence. We used linear mixed-effects models to quantify associations of percent breast density and dense and non-dense breast volume at ages 25-29 with quartiles of age-specific youth body mass index (BMI) Z-scores, adjusting for clinic, treatment group, current adult BMI, and other well-established risk factors for breast cancer and predictors of breast density.
  
  
  RESULTS
  We observed inverse associations between age-specific BMI Z-scores at all youth clinic visits and percent breast density, adjusting for current adult BMI and other covariates (all p values <0.01). Women whose baseline BMI Z-scores (at ages 8-10 years) were in the top quartile had significantly lower adult breast density, after adjusting for current adult BMI and other covariates [least squares mean (LSM): 23.4 %; 95 % confidence interval (CI): 18.0 %, 28.8 %] compared to those in the bottom quartile (LSM: 31.8 %; 95 % CI: 25.2 %, 38.4 %) (p trend <0.01). Significant inverse associations were also observed for absolute dense breast volume (all p values <0.01), whereas there were no clear associations with non-dense breast volume.
  
  
  CONCLUSIONS
  These results support the hypothesis that body fatness during childhood and adolescence may play an important role in premenopausal breast density, independent of current BMI, and further suggest direct or indirect influences on absolute dense breast volume.
  
  
  BACKGROUND
  NCT00458588 ; April 9, 2007.
authors.affiliation: Channing Division of Network Medicine, Brigham and Women's Hospital and Harvard Medical School, 181 Longwood Avenue, Boston, MA, 02115, USA. kbertran@hsph.harvard.edu.|Department of Epidemiology, Harvard T.H. Chan School of Public Health, 677 Huntington Avenue, Boston, MA, 02115, USA. kbertran@hsph.harvard.edu.
authors.forename: Kimberly A
authors.initials: KA
authors.lastname: Bertrand
authors.affiliation: Department of Epidemiology, Harvard T.H. Chan School of Public Health, 677 Huntington Avenue, Boston, MA, 02115, USA. hbaer@partners.org.|Division of General Internal Medicine and Primary Care, Brigham and Women's Hospital and Harvard Medical School, 75 Francis Street, Boston, MA, 02120, USA. hbaer@partners.org.
authors.forename: Heather J
authors.initials: HJ
authors.lastname: Baer
authors.affiliation: Division of General Internal Medicine and Primary Care, Brigham and Women's Hospital and Harvard Medical School, 75 Francis Street, Boston, MA, 02120, USA. eorav@partners.org.|Department of Biostatistics, Harvard T.H. Chan School of Public Health, 677 Huntington Avenue, Boston, MA, 02115, USA. eorav@partners.org.
authors.forename: E John
authors.initials: EJ
authors.lastname: Orav
authors.affiliation: Dangeard Group, 740 chemin de la Commanderie St Jean de Malte, 13080, Luynes, France. catherine@dangeard.com.
authors.forename: Catherine
authors.initials: C
authors.lastname: Klifa
authors.affiliation: Department of Radiology, University of California, 505 Parnassus Avenue, San Francisco, CA, 94143, USA. john.shepherd@ucsf.edu.
authors.forename: John A
authors.initials: JA
authors.lastname: Shepherd
authors.affiliation: Department of Preventive Medicine, Northwestern University, 680 North Lake Shore Drive, Chicago, IL, 60611, USA. lvanhorn@northwestern.edu.
authors.forename: Linda
authors.initials: L
authors.lastname: Van Horn
authors.affiliation: Department of Epidemiology, University of Iowa College of Public Health, 145 North Riverside Drive, Iowa City, IA, 52242, USA. linda-snetselaar@uiowa.edu.
authors.forename: Linda
authors.initials: L
authors.lastname: Snetselaar
authors.affiliation: Kaiser Permanente Center for Health Research, 3800 North Interstate Avenue, Portland, OR, 97227, USA. Victor.J.Stevens@kpchr.org.
authors.forename: Victor J
authors.initials: VJ
authors.lastname: Stevens
authors.affiliation: Department of Radiology, University of California, 505 Parnassus Avenue, San Francisco, CA, 94143, USA. Nola.Hylton@ucsf.edu.
authors.forename: Nola M
authors.initials: NM
authors.lastname: Hylton
authors.affiliation: Department of Epidemiology and Public Health, University of Maryland School of Medicine, 655 West Baltimore Street, Baltimore, MD, 21201, USA. JDorgan@som.umaryland.edu.
authors.forename: Joanne F
authors.initials: JF
authors.lastname: Dorgan
mesh_terms: D000273:Adipose Tissue; D050154:Adiposity; D000328:Adult; D000367:Age Factors; D015992:Body Mass Index; D000071060:Breast Density; D001943:Breast Neoplasms; D002648:Child; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging; D042361:Mammary Glands, Human / Q000002:abnormalities*; D011446:Prospective Studies