{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,22]],"date-time":"2026-10-22T09:44:14Z","timestamp":1792662254080,"version":"4.5.0"},"reference-count":34,"publisher":"Wiley","license":[{"start":{"date-parts":[[2026,10,22]],"date-time":"2026-10-22T00:00:00Z","timestamp":1792627200000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"},{"start":{"date-parts":[[2026,10,22]],"date-time":"2026-10-22T00:00:00Z","timestamp":1792627200000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/doi.wiley.com\/10.1002\/tdm_license_1.1"}],"funder":[{"DOI":"10.13039\/501100003725","name":"National Research Foundation of Korea","doi-asserted-by":"publisher","award":["RS\u20102024\u201000462658"],"award-info":[{"award-number":["RS\u20102024\u201000462658"]}],"id":[{"id":"10.13039\/501100003725","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100003725","name":"National Research Foundation of Korea","doi-asserted-by":"publisher","award":["RS\u20102025\u201000558296"],"award-info":[{"award-number":["RS\u20102025\u201000558296"]}],"id":[{"id":"10.13039\/501100003725","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100003725","name":"National Research Foundation of Korea","doi-asserted-by":"publisher","award":["RS\u20102026\u201025483458"],"award-info":[{"award-number":["RS\u20102026\u201025483458"]}],"id":[{"id":"10.13039\/501100003725","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100002701","name":"Ministry of Education","doi-asserted-by":"publisher","award":["2023R1A6C101A009"],"award-info":[{"award-number":["2023R1A6C101A009"]}],"id":[{"id":"10.13039\/501100002701","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Intl Journal of Cancer"],"abstract":"<jats:title>ABSTRACT<\/jats:title>\n                  <jats:p>We examined the associations of parity and breastfeeding with postmenopausal breast density, longitudinal changes in breast density, and breast cancer risk, and assessed the extent to which breast density mediates these relationships. We analyzed a cohort of women who underwent mammography in 2009\u20132010 and had at least one follow\u2010up mammogram through 2016. Parity and breastfeeding history were self\u2010reported, breast density was classified using Breast Imaging Reporting and Data System (BI\u2010RADS), and relative risks (RRs) were estimated using Poisson regression. Mediation analysis evaluated the contributions of baseline breast density and its longitudinal change. Lower parity and shorter breastfeeding duration were associated with higher baseline breast density and less favorable density trajectories over time, including a greater likelihood of increasing density and a lower likelihood of decreasing density. Compared with women with at least two children who breastfed for &gt;\u200912\u2009months, women with one child who did not breastfeed had a higher breast cancer risk (RR: 1.53; 95% confidence interval [CI]: 1.43\u20131.64), with a clear dose\u2013response pattern across parity and breastfeeding categories. Parity showed stronger associations than breastfeeding duration with both breast density and breast cancer risk, and these associations were generally stronger among women aged 65\u2009years or older. Baseline breast density and its longitudinal change mediated approximately 10%\u201315% of the associations between reproductive factors and breast cancer risk. These findings suggest that reproductive history has long\u2010term effects on breast tissue composition and partly explains subsequent breast cancer risk in postmenopausal women.<\/jats:p>","DOI":"10.1002\/ijc.70796","type":"journal-article","created":{"date-parts":[[2026,10,22]],"date-time":"2026-10-22T09:35:16Z","timestamp":1792661716000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Impact of Childbearing and Breastfeeding on Breast Density Change, and Subsequent Breast Cancer Risk in Postmenopausal Women: A Mediation Analysis"],"prefix":"10.1002","author":[{"given":"Boyoung","family":"Park","sequence":"first","affiliation":[{"name":"Department of Preventive Medicine Hanyang University College of Medicine  Seoul Republic of Korea"},{"name":"Hanyang Institute of Bioscience and Biotechnology Hanyang University  Seoul Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Junghyun","family":"Yoon","sequence":"additional","affiliation":[{"name":"Department of Preventive Medicine Hanyang University College of Medicine  Seoul Republic of Korea"},{"name":"Institute for Health and Society Hanyang University  Seoul Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nguyen Thi Huyen","family":"Trang","sequence":"additional","affiliation":[{"name":"Department of Preventive Medicine Hanyang University College of Medicine  Seoul Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7720-4552","authenticated-orcid":false,"given":"Somin","family":"Jeon","sequence":"additional","affiliation":[{"name":"Department of Preventive Medicine Hanyang University College of Medicine  Seoul Republic of Korea"},{"name":"Institute for Health and Society Hanyang University  Seoul Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2026,10,22]]},"reference":[{"key":"e_1_2_11_2_1","doi-asserted-by":"publisher","DOI":"10.3322\/caac.21834"},{"key":"e_1_2_11_3_1","doi-asserted-by":"crossref","first-page":"187","DOI":"10.1016\/S0140-6736(02)09454-0","article-title":"Collaborative Reanalysis of Individual Data From 47 Epidemiological Studies in 30 Countries, Including 50\u2008302 Women With Breast Cancer and 96\u2008973 Women Without the Disease","volume":"360","author":"Breast cancer and breastfeeding","year":"2002","journal-title":"Lancet"},{"key":"e_1_2_11_4_1","doi-asserted-by":"publisher","DOI":"10.1016\/S0140-6736(15)01024-7"},{"key":"e_1_2_11_5_1","doi-asserted-by":"crossref","DOI":"10.3346\/jkms.2023.38.e261","article-title":"The Current Status of Prolonged Breastfeeding and Its Related Factors in Korean Infants and Their Mothers: A Nationwide Cross\u2010Sectional Study","volume":"38","author":"Hong J.","year":"2023","journal-title":"Journal of Korean Medical Science"},{"key":"e_1_2_11_6_1","doi-asserted-by":"publisher","DOI":"10.3345\/cep.2025.00857"},{"key":"e_1_2_11_7_1","doi-asserted-by":"publisher","DOI":"10.1093\/jbi\/wbaf015"},{"key":"e_1_2_11_8_1","doi-asserted-by":"publisher","DOI":"10.1007\/s10549-016-3884-y"},{"key":"e_1_2_11_9_1","doi-asserted-by":"crossref","first-page":"194","DOI":"10.1186\/s12905-022-01772-4","article-title":"Impact of Childbirth History on Dense Breast in Mammographic Screening: A Cross\u2010Sectional Study","volume":"22","author":"Ochi T.","year":"2022","journal-title":"BMC Women's Health"},{"key":"e_1_2_11_10_1","doi-asserted-by":"publisher","DOI":"10.1158\/2767-9764.CRC-24-0561"},{"key":"e_1_2_11_11_1","first-page":"e15","article-title":"Cohort Profile: The National Health Insurance Service\u2010National Sample Cohort (NHIS\u2010NSC), South Korea","volume":"46","author":"Lee J.","year":"2017","journal-title":"International Journal of Epidemiology"},{"key":"e_1_2_11_12_1","doi-asserted-by":"publisher","DOI":"10.4178\/epih.e2022111"},{"key":"e_1_2_11_13_1","doi-asserted-by":"crossref","first-page":"457","DOI":"10.3346\/jkms.2016.31.3.457","article-title":"Mammographic Breast Density Evaluation in Korean Women Using Fully Automated Volumetric Assessment","volume":"31","author":"Youn I.","year":"2016","journal-title":"Journal of Korean Medical Science"},{"key":"e_1_2_11_14_1","doi-asserted-by":"publisher","DOI":"10.1037\/a0031034"},{"key":"e_1_2_11_15_1","doi-asserted-by":"crossref","first-page":"129","DOI":"10.1007\/s10549-018-4735-9","article-title":"Does Mammographic Density Mediate Risk Factor Associations With Breast Cancer? 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