title: Childhood body mass index and adult mammographic density measures that predict breast cancer risk.
abstract: The aim of the present study is to determine if body mass index (BMI) during childhood is associated with the breast cancer risk factor 'adult mammographic density adjusted for age and BMI'. In 1968, the Tasmanian Longitudinal Health Study studied every Tasmanian school child born in 1961. We obtained measured heights and weights from annual school medical records across ages 7-15 years and imputed missing values. Between 2009 and 2012, we administered to 490 women a questionnaire that asked current height and weight and digitised at least one mammogram per woman. Absolute and percent mammographic densities were measured using the computer-assisted method CUMULUS. We used linear regression and adjusted for age at interview and log current BMI. The mammographic density measures were negatively associated: with log BMI at each age from 7 to 15 years (all p < 0.05); with the average of standardised log BMIs across ages 7-15 years (p < 0.0005); and more strongly with standardised log BMI measures closer to age 15 years (p < 0.03). Childhood BMI measures explained 7 and 10 % of the variance in absolute and percent mammographic densities, respectively, and 25 and 20 % of the association between current BMI and absolute and percent mammographic densities, respectively. Associations were not altered by adjustment for age at menarche. There is a negative association between BMI in late childhood and the adult mammographic density measures that predict breast cancer risk. This could explain, at least in part, why BMI in adolescence is negatively associated with breast cancer risk.
authors.affiliation: Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Level 3, 207 Bouverie Street, Carlton, 3053, VIC, Australia. j.hopper@unimelb.edu.au.|Seoul Department of Epidemiology and Institute of Health and Environment, School of Public Health, Seoul National University, Seoul, Korea. j.hopper@unimelb.edu.au.
authors.forename: John L
authors.identifier: http://orcid.org/0000-0002-8567-173X
authors.initials: JL
authors.lastname: Hopper
authors.affiliation: Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Level 3, 207 Bouverie Street, Carlton, 3053, VIC, Australia.
authors.forename: Tuong L
authors.initials: TL
authors.lastname: Nguyen
authors.affiliation: The Curtin UWA Centre for Genetic Origins of Health and Disease, Curtin University and The University of Western Australia, Perth, WA, Australia.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Stone
authors.affiliation: Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Level 3, 207 Bouverie Street, Carlton, 3053, VIC, Australia.
authors.forename: Kelly
authors.initials: K
authors.lastname: Aujard
authors.affiliation: Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Level 3, 207 Bouverie Street, Carlton, 3053, VIC, Australia.
authors.forename: Melanie C
authors.initials: MC
authors.lastname: Matheson
authors.affiliation: Department of Epidemiology & Preventive Medicine, School of Public Health and Preventive Medicine, Monash University, Melbourne, VIC, Australia.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Abramson
authors.affiliation: Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Level 3, 207 Bouverie Street, Carlton, 3053, VIC, Australia.
authors.forename: John A
authors.initials: JA
authors.lastname: Burgess
authors.affiliation: NHMRC Centre for Research Excellence for Chronic Respiratory Disease, University of Tasmania, Hobart, TAS, Australia.
authors.forename: E Haydn
authors.initials: EH
authors.lastname: Walters
authors.affiliation: Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Level 3, 207 Bouverie Street, Carlton, 3053, VIC, Australia.
authors.forename: Gillian S
authors.initials: GS
authors.lastname: Dite
authors.affiliation: Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Level 3, 207 Bouverie Street, Carlton, 3053, VIC, Australia.
authors.forename: Minh
authors.initials: M
authors.lastname: Bui
authors.affiliation: Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Level 3, 207 Bouverie Street, Carlton, 3053, VIC, Australia.
authors.forename: Christopher
authors.initials: C
authors.lastname: Evans
authors.affiliation: Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Level 3, 207 Bouverie Street, Carlton, 3053, VIC, Australia.
authors.forename: Enes
authors.initials: E
authors.lastname: Makalic
authors.affiliation: Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Level 3, 207 Bouverie Street, Carlton, 3053, VIC, Australia.
authors.forename: Daniel F
authors.initials: DF
authors.lastname: Schmidt
authors.affiliation: Department of Health & Human Services, BreastScreen Tasmania, Level 4 25 Argyle St., Hobart, TAS, Australia.
authors.forename: Gail
authors.initials: G
authors.lastname: Ward
authors.affiliation: Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Level 3, 207 Bouverie Street, Carlton, 3053, VIC, Australia.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Jenkins
authors.affiliation: Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Level 3, 207 Bouverie Street, Carlton, 3053, VIC, Australia.|Cancer Epidemiology Centre, Cancer Council Victoria, St Kilda, VIC, Australia.
authors.forename: Graham G
authors.initials: GG
authors.lastname: Giles
authors.affiliation: Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Level 3, 207 Bouverie Street, Carlton, 3053, VIC, Australia.
authors.forename: Shyamali C
authors.initials: SC
authors.lastname: Dharmage
authors.affiliation: Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Level 3, 207 Bouverie Street, Carlton, 3053, VIC, Australia.
authors.forename: Carmel
authors.initials: C
authors.lastname: Apicella
mesh_terms: D000293:Adolescent; D015992:Body Mass Index; D000071060:Breast Density; D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D002648:Child; D055088:Early Detection of Cancer; D005260:Female; D006801:Humans; D016014:Linear Models; D008137:Longitudinal Studies; D008327:Mammography; D008875:Middle Aged; D012307:Risk Factors; D013648:Tasmania
keywords: Adolescence; Body mass index; Breast cancer; Childhood growth; Mammographic density; Prospective study