title: The impact of breast cancer-specific birth cohort effects among younger and older Chinese populations.
abstract: Historically low breast cancer incidence rates among Asian women have risen worldwide; purportedly due to the adoption of a "Western" life style among younger generations (i.e., the more recent birth cohorts). However, no study has simultaneously compared birth cohort effects between both younger and older women in different Asian and Western populations. Using cancer registry data from rural and urban China, Singapore and the United States (1990-2008), we estimated age-standardized incidence rates (ASR), annual percentage change (EAPC) in the ASR, net drifts, birth cohort specific incidence rates and cohort rate ratios (CRR). Younger (30-49 years, 1943-1977 birth cohorts) and older women (50-79 years; 1913-1957 birth cohorts) were assessed separately. CRRs among Chinese populations were estimated using birth cohort specific rates with US non-Hispanic white women (NHW) serving as the reference population with an assigned CRR of 1.0. We observed higher EAPCs and net drifts among those Chinese populations with lower ASRs. Similarly, we observed the most rapidly increasing cohort-specific incidence rates among those Chinese populations with the lowest baseline CRRs. Both trends were more significant among older than younger women. Average CRRs were 0.06-0.44 among older and 0.18-0.81 among younger women. Rapidly rising cohort specific rates have narrowed the historic disparity between Chinese and US NHW breast cancer populations particularly in regions with the lowest baseline rates and among older women. Future analytic studies are needed to investigate risk factors accounting for the rapid increase of breast cancer among older and younger women separately in Asian populations.
authors.affiliation: Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, MD.
authors.forename: Hyuna
authors.initials: H
authors.lastname: Sung
authors.affiliation: Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, MD.
authors.forename: Philip S
authors.initials: PS
authors.lastname: Rosenberg
authors.affiliation: National Office for Cancer Prevention and Control and National Central Cancer Registry, National Cancer Center, Beijing, China.
authors.forename: Wan-Qing
authors.initials: WQ
authors.lastname: Chen
authors.affiliation: Department of Medical Epidemiology and Biostatistics, Karolinska Institute, Stockholm, Sweden.|Saw Swee Hock School of Public Health, National University of Singapore, Singapore.|Department of Surgery, National University of Singapore, Singapore.
authors.forename: Mikael
authors.initials: M
authors.lastname: Hartman
authors.affiliation: Saw Swee Hock School of Public Health, National University of Singapore, Singapore.
authors.forename: Wei-Yen
authors.initials: WY
authors.lastname: Lim
authors.affiliation: Saw Swee Hock School of Public Health, National University of Singapore, Singapore.
authors.forename: Kee Seng
authors.initials: KS
authors.lastname: Chia
authors.affiliation: Hong Kong Cancer Registry, Hospital Authority, Hong Kong SAR, China.
authors.forename: Oscar
authors.initials: O
authors.lastname: Wai-Kong Mang
authors.affiliation: Division of Occupational and Environmental Health, JC School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong SAR, China.
authors.forename: Lapah
authors.initials: L
authors.lastname: Tse
authors.affiliation: Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, MD.
authors.forename: William F
authors.initials: WF
authors.lastname: Anderson
authors.affiliation: Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, MD.
authors.forename: Xiaohong R
authors.initials: XR
authors.lastname: Yang
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D001213:Asian / Q000706:statistics & numerical data*; D044466:Asian People / Q000706:statistics & numerical data*; D001943:Breast Neoplasms / Q000453:epidemiology* / Q000266:history; D002681:China / Q000453:epidemiology; D015331:Cohort Studies; D005260:Female; D049673:History, 20th Century; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D012042:Registries; D018426:SEER Program; D012846:Singapore / Q000453:epidemiology; D014481:United States / Q000453:epidemiology
keywords: China; age group; birth cohort effect; breast cancer; westernization