title: Differential impact of body mass index on absolute and percent breast density: implications regarding their use as breast cancer risk biomarkers.
abstract: Percent breast density (PBD), a commonly used biomarker of breast cancer risk (BCR), is confounded by the influence of non-dense breast tissue on its measurement and factors, such as BMI, which have an impact on non-dense tissue. Consequently, BMI, a potent BCR factor, is, paradoxically, negatively correlated with PBD. We propose that absolute breast density (ABD) is a more accurate biomarker of BCR. We used a volumetric method to compare the correlation between PBD and ABD with baseline demographics and dietary and physical activity variables in a group of 169 postmenopausal women enrolled in a clinical trial prior to any intervention. As expected, a strong negative correlation between PBD and BMI was observed (Rho = -0.5, p < 5e(-12)). In contrast, we observed a strong, previously not well established, positive correlation of BMI with ABD (Rho = 0.41, p < 2.5e(-8)), which supports the use of ABD as a more accurate indicator of BCR. Correction of PBD by BMI did not frequently provide the same information as ABD. In addition, because of the strong influence of BMI on ABD, many correlations between dietary variables and ABD did not emerge, until adjustment was made for BMI. ABD corrected by BMI should be the gold standard BD measurement. These findings identify the optimal measurement of BD when testing the influence of an intervention on BD as a biomarker of BCR.
authors.affiliation: Departments of Radiology, Pennsylvania State University College of Medicine, Hershey, PA, USA.
authors.forename: Susann E
authors.initials: SE
authors.lastname: Schetter
authors.forename: Terryl J
authors.initials: TJ
authors.lastname: Hartman
authors.forename: Jason
authors.initials: J
authors.lastname: Liao
authors.forename: John P
authors.initials: JP
authors.lastname: Richie
authors.forename: Bogdan
authors.initials: B
authors.lastname: Prokopczyk
authors.forename: Cindy
authors.initials: C
authors.lastname: DuBrock
authors.forename: Carina
authors.initials: C
authors.lastname: Signori
authors.forename: Christopher
authors.initials: C
authors.lastname: Hamilton
authors.forename: Laurence M
authors.initials: LM
authors.lastname: Demers
authors.forename: Karam
authors.initials: K
authors.lastname: El-Bayoumy
authors.forename: Andrea
authors.initials: A
authors.lastname: Manni
mesh_terms: D015502:Absorptiometry, Photon; D000328:Adult; D000368:Aged; D015415:Biomarkers; D015992:Body Mass Index; D001943:Breast Neoplasms / Q000453:epidemiology / Q000209:etiology / Q000473:pathology; D004032:Diet; D005260:Female; D006801:Humans; D008327:Mammography; D008875:Middle Aged; D009043:Motor Activity; D012307:Risk Factors
chemical_list: D015415:Biomarkers