title: The effect of change in body mass index on volumetric measures of mammographic density.
abstract: BACKGROUND
  Understanding how changes in body mass index (BMI) relate to changes in mammographic density is necessary to evaluate adjustment for BMI gain/loss in studies of change in density and breast cancer risk. Increase in BMI has been associated with a decrease in percent density, but the effect on change in absolute dense area or volume is unclear.
  
  
  METHODS
  We examined the association between change in BMI and change in volumetric breast density among 24,556 women in the San Francisco Mammography Registry from 2007 to 2013. Height and weight were self-reported at the time of mammography. Breast density was assessed using single x-ray absorptiometry measurements. Cross-sectional and longitudinal associations between BMI and dense volume (DV), non-dense volume (NDV), and percent dense volume (PDV) were assessed using multivariable linear regression models, adjusted for demographics, risk factors, and reproductive history.
  
  
  RESULTS
  In cross-sectional analysis, BMI was positively associated with DV [β, 2.95 cm(3); 95% confidence interval (CI), 2.69-3.21] and inversely associated with PDV (β, -2.03%; 95% CI, -2.09, -1.98). In contrast, increasing BMI was longitudinally associated with a decrease in both DV (β, -1.01 cm(3); 95% CI, -1.59, -0.42) and PDV (β, -1.17%; 95% CI, -1.31, -1.04). These findings were consistent for both pre- and postmenopausal women.
  
  
  CONCLUSIONS
  Our findings support an inverse association between change in BMI and change in PDV. The association between increasing BMI and decreasing DV requires confirmation.
  
  
  CONCLUSIONS
  Longitudinal studies of PDV and breast cancer risk, or those using PDV as an indicator of breast cancer risk, should evaluate adjustment for change in BMI.
authors: Department of Surgery and Office of Health Promotion Research, University of Vermont, Burlington, Vermont. Department of Biostatistics and Epidemiology, University of Massachusetts Amherst, Amherst, Massachusetts. victoria.hart@uvm.edu.
authors: Vicki
authors: V
authors: Hart
authors: Department of Biostatistics and Epidemiology, University of Massachusetts Amherst, Amherst, Massachusetts.
authors: Katherine W
authors: KW
authors: Reeves
authors: Department of Biostatistics and Epidemiology, University of Massachusetts Amherst, Amherst, Massachusetts.
authors: Susan R
authors: SR
authors: Sturgeon
authors: Department of Biostatistics and Epidemiology, University of Massachusetts Amherst, Amherst, Massachusetts.
authors: Nicholas G
authors: NG
authors: Reich
authors: Department of Anthropology, University of Massachusetts Amherst, Amherst, Massachusetts.
authors: Lynnette Leidy
authors: LL
authors: Sievert
authors: Division of General Internal Medicine, Department of Medicine, University of California San Francisco, San Francisco, California.
authors: Karla
authors: K
authors: Kerlikowske
authors: Division of General Internal Medicine, Department of Medicine, University of California San Francisco, San Francisco, California.
authors: Lin
authors: L
authors: Ma
authors: Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California.
authors: John
authors: J
authors: Shepherd
authors: Division of General Internal Medicine, Department of Medicine, University of California San Francisco, San Francisco, California.
authors: Jeffrey A
authors: JA
authors: Tice
authors: Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California.
authors: Amir Pasha
authors: AP
authors: Mahmoudzadeh
authors: Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California.
authors: Serghei
authors: S
authors: Malkov
authors: Department of Surgery and Office of Health Promotion Research, University of Vermont, Burlington, Vermont.
authors: Brian L
authors: BL
authors: Sprague
mesh_terms: D015992:Body Mass Index; D001940:Breast / Q000473:pathology; D000071060:Breast Density; D001943:Breast Neoplasms / Q000175:diagnosis / Q000473:pathology*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D016014:Linear Models; D008137:Longitudinal Studies; D042361:Mammary Glands, Human / Q000002:abnormalities* / Q000473:pathology; D008327:Mammography / Q000379:methods / Q000592:standards; D008875:Middle Aged; D012307:Risk Factors