title: Body fat and breast cancer risk in postmenopausal women: a longitudinal study.
abstract: Associations between anthropometric indices of obesity and breast cancer risk may fail to capture the true relationship between excess body fat and risk. We used dual-energy-X-ray-absorptiometry- (DXA-) derived measures of body fat obtained in the Women's Health Initiative to examine the association between body fat and breast cancer risk; we compared these risk estimates with those for conventional anthropometric measurements. The study included 10,960 postmenopausal women aged 50-79 years at recruitment, with baseline DXA measurements and no history of breast cancer. During followup (median: 12.9 years), 503 incident breast cancer cases were diagnosed. Hazard ratios (HR) and 95% confidence intervals (CI) were estimated using Cox proportional hazards models. All baseline DXA-derived body fat measures showed strong positive associations with breast cancer risk. The multivariable-adjusted HR for the uppermost quintile level (versus lowest) ranged from 1.53 (95% CI 1.14-2.07) for fat mass of the right leg to 2.05 (1.50-2.79) for fat mass of the trunk. Anthropometric indices (categorized by quintiles) of obesity (BMI (1.97, 1.45-2.68), waist circumference (1.97, 1.46-2.65), and waist : hip ratio (1.91, 1.41-2.58)) were all strongly, positively associated with risk and did not differ from DXA-derived measures in prediction of risk.
authors.affiliation: Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Rohan
authors.forename: Moonseong
authors.initials: M
authors.lastname: Heo
authors.forename: Lydia
authors.initials: L
authors.lastname: Choi
authors.forename: Mridul
authors.initials: M
authors.lastname: Datta
authors.forename: Jo L
authors.initials: JL
authors.lastname: Freudenheim
authors.forename: Victor
authors.initials: V
authors.lastname: Kamensky
authors.forename: Heather M
authors.initials: HM
authors.lastname: Ochs-Balcom
authors.forename: Lihong
authors.initials: L
authors.lastname: Qi
authors.forename: Cynthia A
authors.initials: CA
authors.lastname: Thomson
authors.forename: Mara Z
authors.initials: MZ
authors.lastname: Vitolins
authors.forename: Sylvia
authors.initials: S
authors.lastname: Wassertheil-Smoller
authors.forename: Geoffrey C
authors.initials: GC
authors.lastname: Kabat