title: Population attributable risks of modifiable reproductive factors for breast and ovarian cancers in Korea.
abstract: BACKGROUND
  Breast and ovarian cancers are predominant female cancers with increasing prevalence. The purpose of this study was to estimate the population attributable risks (PARs) of breast and ovarian cancer occurrence based on the relative risks (RRs) of modifiable reproductive factors and population-specific exposure prevalence.
  
  
  METHODS
  The PAR was calculated by using the 1990 standardized prevalence rates, the 2010 national cancer incidence with a 20 year lag period, the meta-analyzed RRs from studies conducted in the Korean population for breast cancer, and the meta-analyzed RRs from a Korean epithelial ovarian cancer study and a prior meta-analysis, and ovarian cancer cohort results up to 2012. For oral contraceptive and hormone replacement therapy use, we did not consider lag period.
  
  
  RESULTS
  The summary PARs for modifiable reproductive factors were 16.7% (95% CI 15.8-17.6) for breast cancer (2404 cases) and 81.9% (95% CI 55.0-100.0) for ovarian cancer (1579 cases). The modifiable reproductive factors included pregnancy/age at first birth (8.0%), total period of breastfeeding (3.1%), oral contraceptive use (5.3%), and hormone replacement therapy use (0.3%) for breast cancer and included breastfeeding experience (2.9%), pregnancy (1.2%), tubal ligation (24.5%), and oral contraceptive use (53.3%) for ovarian cancer.
  
  
  CONCLUSIONS
  Despite inherent uncertainties in the risk factors for breast and ovarian cancers, we suggest that appropriate long-term control of modifiable reproductive factors could reduce breast and ovarian cancer incidences and their related burdens by 16.7% and 81.9%, respectively.
authors.affiliation: Graduate School of Cancer Science and Policy, Goyang, Korea. hayejine@ncc.re.kr.|National Cancer Control Institute, National Cancer Center, Goyang, Korea. hayejine@ncc.re.kr.
authors.forename: Boyoung
authors.initials: B
authors.lastname: Park
authors.affiliation: National Cancer Control Institute, National Cancer Center, Goyang, Korea. SOHEEPARK@yuhs.ac.|Department of Epidemiology and Health Promotion, Graduate School of Public Health, Yonsei University, Seoul, Korea. SOHEEPARK@yuhs.ac.
authors.forename: Sohee
authors.initials: S
authors.lastname: Park
authors.affiliation: Western Pacific Regional Office, World Health Organization, Manila, Philippines. Shinh@wpro.who.int.
authors.forename: Hai-Rim
authors.initials: HR
authors.lastname: Shin
authors.affiliation: Graduate School of Cancer Science and Policy, Goyang, Korea. shinaesun@snu.ac.kr.|Department of Preventive Medicine, Seoul National University College of Medicine, 103 Daehakro, Chongno-gu, Seoul, 110-799, Korea. shinaesun@snu.ac.kr.
authors.forename: Aesun
authors.initials: A
authors.lastname: Shin
authors.affiliation: Department of Preventive Medicine, Seoul National University College of Medicine, 103 Daehakro, Chongno-gu, Seoul, 110-799, Korea. hanyoung290@snu.ac.kr.
authors.forename: Yohwan
authors.initials: Y
authors.lastname: Yeo
authors.affiliation: Department of Biomedical Science, Seoul National University Graduate School, Seoul, Korea. miso77@snu.ac.kr.
authors.forename: Ji-Yeob
authors.initials: JY
authors.lastname: Choi
authors.affiliation: National Cancer Control Institute, National Cancer Center, Goyang, Korea. ara@ncc.re.kr.
authors.forename: Kyu-Won
authors.initials: KW
authors.lastname: Jung
authors.affiliation: Department of Obstetrics and Gynecology, Samsung Medical Center & Sungkyunkwan University School of Medicine, Seoul, Korea. bgkim@skku.edu.
authors.forename: Byoung-Gie
authors.initials: BG
authors.lastname: Kim
authors.affiliation: Department of Obstetrics and Gynecology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea. ymkim@amc.seoul.kr.
authors.forename: Yong-Man
authors.initials: YM
authors.lastname: Kim
authors.affiliation: Department of Surgery and Cancer Research Institute, Seoul National University College of Medicine, Seoul, Korea. dynoh@snu.ac.kr.
authors.forename: Dong-Young
authors.initials: DY
authors.lastname: Noh
authors.affiliation: Department of Surgery, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea. ahnsh@amc.seoul.kr.
authors.forename: Sei-Hyun
authors.initials: SH
authors.lastname: Ahn
authors.affiliation: Department of Obstetrics and Gynecology, Seoul National University Hospital and Seoul National University College of Medicine, Seoul, Korea. kjwksh@gmail.com.
authors.forename: Jae Weon
authors.initials: JW
authors.lastname: Kim
authors.affiliation: Department of Gynecologic Oncology, National Cancer Center, Goyang, Korea. sokbom@ncc.re.kr.
authors.forename: Sokbom
authors.initials: S
authors.lastname: Kang
authors.affiliation: Department of Obstetrics and Gynecology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea. jaehoonkim@yuhs.ac.kr.
authors.forename: Jae Hoon
authors.initials: JH
authors.lastname: Kim
authors.affiliation: Department of Obstetrics and Gynecology, Cheil General Hospital and Women's Healthcare Center, Dankook University Medical College, Seoul, Korea. kimonc@hotmail.com.
authors.forename: Tae Jin
authors.initials: TJ
authors.lastname: Kim
authors.affiliation: Department of Preventive Medicine, Seoul National University College of Medicine, 103 Daehakro, Chongno-gu, Seoul, 110-799, Korea. dhkang@snu.ac.kr.|Department of Biomedical Science, Seoul National University Graduate School, Seoul, Korea. dhkang@snu.ac.kr.|Cancer Research Institute, Seoul National University, Seoul, Korea. dhkang@snu.ac.kr.
authors.forename: Daehee
authors.initials: D
authors.lastname: Kang
authors.affiliation: Department of Preventive Medicine, Seoul National University College of Medicine, 103 Daehakro, Chongno-gu, Seoul, 110-799, Korea. bkkyyoo@gmail.com.
authors.forename: Keun-Young
authors.initials: KY
authors.lastname: Yoo
authors.affiliation: Department of Preventive Medicine, Seoul National University College of Medicine, 103 Daehakro, Chongno-gu, Seoul, 110-799, Korea. suepark@snu.ac.kr.|Department of Biomedical Science, Seoul National University Graduate School, Seoul, Korea. suepark@snu.ac.kr.|Cancer Research Institute, Seoul National University, Seoul, Korea. suepark@snu.ac.kr.
authors.forename: Sue K
authors.initials: SK
authors.lastname: Park
mesh_terms: D000328:Adult; D001943:Breast Neoplasms / Q000453:epidemiology* / Q000503:physiopathology; D003276:Contraceptives, Oral / Q000009:adverse effects; D005260:Female; D006801:Humans; D008423:Maternal Age; D010051:Ovarian Neoplasms / Q000453:epidemiology* / Q000503:physiopathology; D011247:Pregnancy; D012098:Reproduction / Q000502:physiology*; D017584:Reproductive History; D056910:Republic of Korea; D012307:Risk Factors
chemical_list: D003276:Contraceptives, Oral