title: Pregnancy-Associated Risk Factors of Postpartum Breast Cancer in Korea: A Nationwide Health Insurance Database Study.
abstract: Patients with postpartum breast cancer have been reported to have a poor prognosis. The present study aimed to evaluate the pregnancy-related risk factors of postpartum breast cancer in Korea. We collected patient data from the Korea National Health Insurance (KNHI) Claims Database of the Health Insurance Review and Assessment Service (HIRA) for the 2009-2013 period. We evaluated the pregnancy-related risk factors for postpartum breast cancer in two population groups. For Group 1 (women who had given birth during the 2010-2012 period), data on those who were diagnosed with breast cancer from childbirth to 1-year postpartum were extracted. For Group 2, we extracted the data of women who gave birth in 2010 and traced them until December 31, 2013. In Group 1, 1,384,551 deliveries and 317 postpartum breast cancer patients were recorded in Korea between January 1, 2010, and December 31, 2012. Women aged ≥35 years (Odds Ratio [OR], 2.003; 95% Confidence Interval [CI], 1.567-2.560) and those who gave birth via cesarean delivery (OR, 1.237; 95% CI, 0.986-1.553) were considered to be at a higher risk for breast cancer. Lower risk was noted in primiparous women (OR, 0.737; 95% CI, 0.585-0.928). In Group 2, the data of 457,924 women who gave birth in 2010 were traced until December 31, 2013. Among them, 655 patients were diagnosed with breast cancer, and age ≥35 years and cesarean delivery were associated with an higher risk of breast cancer, whereas primiparous status was associated with a lower risk of breast cancer. In conclusion, older age (≥35 years) and cesarean delivery are significant risk factors for postpartum breast cancer, and primiparous women have a lower risk of developing postpartum breast cancer.
authors.affiliation: Division of Hemato-oncology, Department of Internal Medicine, Korea University Guro Hospital, Korea University College of Medicine, Seoul, Korea.
authors.forename: Eun Joo
authors.initials: EJ
authors.lastname: Kang
authors.affiliation: Division of Hemato-oncology, Department of Internal Medicine, Korea University Guro Hospital, Korea University College of Medicine, Seoul, Korea.
authors.forename: Jae Hong
authors.initials: JH
authors.lastname: Seo
authors.affiliation: The Health Insurance Review & Assessment Service of Korea, Seoul, Korea.
authors.forename: Log Young
authors.initials: LY
authors.lastname: Kim
authors.affiliation: Department of Applied Statistics, Chung-Ang University, Seoul, Korea.
authors.forename: Geun U
authors.initials: GU
authors.lastname: Park
authors.affiliation: Department of Obstetrics and Gynecology, Korea University College of Medicine, Seoul, Korea.
authors.forename: Min-Jeong
authors.initials: MJ
authors.lastname: Oh
authors.affiliation: Division of Transplant and Vascular Surgery, Department of Surgery, Korea University Guro Hospital, Korea University College of Medicine, Seoul, Korea.
authors.forename: Pyoung-Jae
authors.initials: PJ
authors.lastname: Park
authors.affiliation: Department of Obstetrics and Gynecology, Korea University College of Medicine, Seoul, Korea.
authors.forename: Geum Joon
authors.initials: GJ
authors.lastname: Cho
mesh_terms: D000328:Adult; D001943:Breast Neoplasms / Q000453:epidemiology*; D016208:Databases, Factual; D036861:Delivery, Obstetric; D005260:Female; D006801:Humans; D007348:Insurance, Health; D016017:Odds Ratio; D049590:Postpartum Period; D056910:Republic of Korea / Q000453:epidemiology; D012307:Risk Factors