title: Dietary Energy Density and Postmenopausal Breast Cancer Incidence in the Cancer Prevention Study II Nutrition Cohort.
abstract: BACKGROUND
  Dietary energy density (ED) is a measure of diet quality that estimates the amount of energy per unit of food (kilocalories per gram) consumed. Low-ED diets are generally high in fiber and fruits and vegetables and low in fat. Dietary ED has been positively associated with body mass index (BMI) and other risk factors for postmenopausal breast cancer.
  
  
  OBJECTIVE
  We evaluated the associations of total dietary ED and energy-dense (high-ED) foods with postmenopausal breast cancer incidence.
  
  
  METHODS
  Analyses included 56,795 postmenopausal women from the Cancer Prevention Study II Nutrition Cohort with no previous history of breast or other cancers and who provided information on diet, lifestyle, and medical history in 1999. Multivariable-adjusted breast cancer incidence rate ratios (RRs and 95% CIs) were estimated for quintiles of total dietary ED and for the consumption of high-ED foods in Cox proportional hazards regression models.
  
  
  RESULTS
  During a median follow-up of 11.7 y, 2509 invasive breast cancer cases were identified, including 1857 estrogen receptor-positive and 277 estrogen receptor-negative tumors. Median dietary ED was 1.5 kcal/g (IQR: 1.3-1.7 kcal/g). After adjusting for age, race, education, reproductive characteristics, and family history, high compared with low dietary ED was associated with a statistically significantly higher risk of breast cancer (RR for fifth quintile compared with first quintile: 1.20; 95% CI: 1.05, 1.36; P-trend = 0.03). The association between the amount of high-ED foods consumed and breast cancer risk was not statistically significant. We observed no differences by estrogen receptor status or effect modification by BMI, age, or physical activity.
  
  
  CONCLUSIONS
  These results suggest a modest positive association between total dietary ED and risk of postmenopausal breast cancer.
authors.affiliation: Department of Epidemiology, Rollins School of Public Health, Winship Cancer Institute, Emory University, Atlanta, GA; and tjhartm@emory.edu.
authors.forename: Terryl J
authors.initials: TJ
authors.lastname: Hartman
authors.affiliation: Epidemiology Research Program, American Cancer Society, Atlanta, GA.
authors.forename: Susan M
authors.initials: SM
authors.lastname: Gapstur
authors.affiliation: Epidemiology Research Program, American Cancer Society, Atlanta, GA.
authors.forename: Mia M
authors.initials: MM
authors.lastname: Gaudet
authors.affiliation: Epidemiology Research Program, American Cancer Society, Atlanta, GA.
authors.forename: Roma
authors.initials: R
authors.lastname: Shah
authors.affiliation: Department of Epidemiology, Rollins School of Public Health, Winship Cancer Institute, Emory University, Atlanta, GA; and.
authors.forename: W Dana
authors.initials: WD
authors.lastname: Flanders
authors.affiliation: Epidemiology Research Program, American Cancer Society, Atlanta, GA.
authors.forename: Ying
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Epidemiology Research Program, American Cancer Society, Atlanta, GA.
authors.forename: Marjorie L
authors.initials: ML
authors.lastname: McCullough
mesh_terms: D000368:Aged; D001943:Breast Neoplasms / Q000453:epidemiology* / Q000517:prevention & control*; D015331:Cohort Studies; D000072001:Diet, Healthy; D004043:Dietary Fiber / Q000008:administration & dosage / Q000032:analysis; D002149:Energy Intake; D005260:Female; D005500:Follow-Up Studies; D005638:Fruit; D006801:Humans; D015994:Incidence; D008019:Life Style; D008875:Middle Aged; D015596:Nutrition Assessment; D009752:Nutritional Status; D017698:Postmenopause; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012307:Risk Factors; D014675:Vegetables
keywords: breast cancer; diet; energy density; obesity; postmenopausal women