title: Dietary energy density is positively associated with breast density among young women.
abstract: BACKGROUND
  Breast density is an established predictor of breast cancer risk, and there is considerable interest in associations of modifiable lifestyle factors, such as diet, with breast density.
  
  
  OBJECTIVE
  To determine whether dietary energy density (ED) is associated with percent dense breast volume (%DBV) and absolute dense breast volume (ADBV) in young women.
  
  
  METHODS
  A cross-sectional analysis was conducted with women who participated in the Dietary Intervention Study in Children Follow-Up Study. %DBV and ADBV were measured by magnetic resonance imaging. Diet was assessed by three 24-hour recalls. Dietary ED (kilocalories/gram) was calculated using three methods: food only, food and caloric beverages, and food and all beverages.
  
  
  METHODS
  One hundred seventy-two women (aged 25 to 29 years) who were enrolled in the Dietary Intervention Study in Children Follow-Up Study. Participants who reported breast augmentation or reduction surgery or were pregnant or lactating within 3 months before breast density assessment were excluded.
  
  
  METHODS
  ADBV and %DBV.
  
  
  METHODS
  Multivariable linear mixed effects models were used. Final models were adjusted for race, smoking status, education, parity, duration of sex hormone use, whole body percent fat, childhood body mass index z score, and energy from beverages.
  
  
  RESULTS
  After adjustment, each 1 kcal/g unit increase in food-only ED was associated with a 25.9% (95% CI 6.2% to 56.8%) increase in %DBV (P=0.01). Childhood body mass index z score modified the association between food-only ED and %DBV such that a significant positive association was observed only in women who were heavier as children. Food-only ED was not associated with ADBV in all women, but a borderline significant positive association was observed in women who had higher childhood body mass index z scores.
  
  
  CONCLUSIONS
  This is the first report to suggest a potential role for dietary ED in breast density; the effects of long-term exposure to high-ED diets on breast cancer risk remain unknown.
authors.forename: Jessica A
authors.initials: JA
authors.lastname: Jones
authors.forename: Terryl J
authors.initials: TJ
authors.lastname: Hartman
authors.forename: Catherine S
authors.initials: CS
authors.lastname: Klifa
authors.forename: Donna L
authors.initials: DL
authors.lastname: Coffman
authors.forename: Diane C
authors.initials: DC
authors.lastname: Mitchell
authors.forename: Jacqueline A
authors.initials: JA
authors.lastname: Vernarelli
authors.forename: Linda G
authors.initials: LG
authors.lastname: Snetselaar
authors.forename: Linda
authors.initials: L
authors.lastname: Van Horn
authors.forename: Victor J
authors.initials: VJ
authors.lastname: Stevens
authors.forename: Alan M
authors.initials: AM
authors.lastname: Robson
authors.forename: John H
authors.initials: JH
authors.lastname: Himes
authors.forename: John A
authors.initials: JA
authors.lastname: Shepherd
authors.forename: Joanne F
authors.initials: JF
authors.lastname: Dorgan
mesh_terms: D015502:Absorptiometry, Photon; D050154:Adiposity / Q000502:physiology; D000328:Adult; D001823:Body Composition / Q000502:physiology; D015992:Body Mass Index; D001940:Breast / Q000033:anatomy & histology* / Q000648:ultrastructure; D003430:Cross-Sectional Studies; D004032:Diet / Q000379:methods*; D002149:Energy Intake / Q000502:physiology*; D005247:Feeding Behavior / Q000502:physiology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging; D015999:Multivariate Analysis
keywords: Breast cancer; Breast density; Diet; Dietary energy density; Premenopausal women