title: Age-Period-Cohort Analysis of Female Breast Cancer Mortality in Korea.
abstract: OBJECTIVE
  Despite the low mortality rate of breast cancer among women in Korea, the breast cancer mortality rate has increased. The aim of this study was to examine trends in breast cancer mortality from 1983 to 2012 in Korea, assessing the importance of age, period, and birth cohort as risk factors.
  
  
  METHODS
  Data on the annual number of deaths due to female breast cancer and on female population statistics from 1983 to 2012 were obtained from Statistics Korea. A log-linear Poisson age-period-cohort model was used to estimate age, period, and cohort effects.
  
  
  RESULTS
  The increasing breast cancer mortality can be explained predominantly by a birth cohort effect: the risk of breast cancer death showed a steady increase until the 1968 birth cohort, and decreased thereafter. There was a sharp increase in the magnitude of the age effect up to 60 years old, then a moderate increase in the effect during the sixties, followed by another sharp increase from 70 years old. The period effect on breast cancer mortality seems negligible based on its adjusted relative risk, even though it was statistically significant after adjusting for age and cohort effects.
  
  
  CONCLUSIONS
  In this study, the mortality pattern of breast cancer in Korea can be explained predominantly by a birth cohort effect. Hence, the overall mortality rate of breast cancer may increase for a while, and show a gradual decrease in the future, which will start from the younger age group.
authors.affiliation: Division of Medical Statistics, Medical Research Collaborating Center, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Yunhee
authors.initials: Y
authors.lastname: Choi
authors.affiliation: Independent Researcher, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Yeonju
authors.initials: Y
authors.lastname: Kim
authors.affiliation: Department of Preventive Medicine, Seoul National University College of Medicine, Seoul, Korea ; Department of Biomedical Science, Seoul National University Graduate School, Seoul, Korea ; Cancer Research Institute, Seoul National University, Seoul, Korea.
authors.forename: Sue K
authors.initials: SK
authors.lastname: Park
authors.affiliation: Division of Cancer Registration and Surveillance, National Cancer Center, Goyang, Korea.
authors.forename: Hai-Rim
authors.initials: HR
authors.lastname: Shin
authors.affiliation: Department of Preventive Medicine, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Keun-Young
authors.initials: KY
authors.lastname: Yoo
mesh_terms: D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000401:mortality*; D015988:Cohort Effect; D015331:Cohort Studies; D005260:Female; D005544:Forecasting; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D056910:Republic of Korea / Q000453:epidemiology; D012307:Risk Factors; D055815:Young Adult
keywords: Breast neoplasms; Cohort effect; Death; Linear models