Reproductive and lifestyle factors related to breast cancer among Japanese women: An observational cohort study

Liu, Rong; Kitamura, Yuri; Kitamura, Tetsuhisa; Sobue, Tomotaka; Sado, Junya; Sugawara, Yumi; Matsuo, Keitaro; Nakayama, Tomio; Tsuji, Ichiro; Ito, Hidemi; Suzuki, Takaichiro; Katanoda, Kota; Tominaga, Suketami

doi:https://doi.org/10.1097/MD.0000000000018315

Reproductive and lifestyle factors related to breast cancer among Japanese women: An observational cohort study

Liu, Rong; Kitamura, Yuri; Kitamura, Tetsuhisa et al.

Medicine (United States), 2019, 98(51), e18315

Number of Access:1,338（2025-12-11 22:39 Counts）

Identifier to cite or link to this item: https://hdl.handle.net/11094/78378

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Title	Reproductive and lifestyle factors related to breast cancer among Japanese women: An observational cohort study
Creator	CreatorName Liu, Rong
	NRID 1000090294074 1000090294074 CreatorName Kitamura, Yuri
	NRID 1000030639810 1000030639810 ORCID 0000-0003-0107-0580 0000-0003-0107-0580 researchmap permalink Kitamura_T Kitamura_T Scopus Author ID 22234282700 22234282700 CreatorName Kitamura, Tetsuhisa
	NRID 1000050270674 1000050270674 researchmap permalink read_0159567 read_0159567 Scopus Author ID 7005649935 7005649935 CreatorName Sobue, Tomotaka
	CreatorName Sado, Junya
	NRID 1000020747456 1000020747456 CreatorName Sugawara, Yumi
	NRID 1000080393122 1000080393122 CreatorName Matsuo, Keitaro
	NRID 1000060501822 1000060501822 CreatorName Nakayama, Tomio
	NRID 1000020171994 1000020171994 CreatorName Tsuji, Ichiro
	NRID 1000090393123 1000090393123 CreatorName Ito, Hidemi
	CreatorName Suzuki, Takaichiro
	NRID 1000000356263 1000000356263 CreatorName Katanoda, Kota
	NRID 1000030124530 1000030124530 CreatorName Tominaga, Suketami
Subject	body mass index
	breast cancer
	cohort
	epidemiology
	reproductive factors
Description	Liu R, Kitamura Y, Kitamura T, Sobue T, Sado J, Sugawara Y, Matsuo K, Nakayama T, Tsuji I, Ito H, Suzuki T, Katanoda K, Tominaga S. Reproductive and lifestyle factors related to breast cancer among Japanese women: An observational cohort study. Medicine 2019;98:51(e18315).
Abstract	The incidence of breast cancer among Japanese women is substantially increasing. This study evaluated the effects of reproductive and lifestyle factors with respect to breast cancer overall and separately among pre- and postmenopausal women using data from the Three-Prefecture Cohort Study of Japan.A total of 33,410 women aged 40 to 79 years completed a self-administered questionnaire, which included items about menstrual and reproductive history and other lifestyle factors. The follow-up period was from 1984 to 1992 in Miyagi and 1985 to 2000 in Aichi Prefectures. We used Cox proportional hazards regression models to estimate hazards ratios (HRs) and 95% confidence intervals (CIs) after adjusting for confounding factors.After 9.8 mean years of follow-up, 287 cases of breast cancer were recorded. In the overall analysis, later menarche (≥16 years) and parity were significantly associated with a decreased risk of breast cancer, with HRs of 0.69 (95% CI 0.48-0.99) and 0.72 (95% CI 0.52-0.99), respectively. Further, there was a significant decline in the risk of breast cancer with increasing number of birth among parous women (P for trend=.010). On the contrary, a family history of breast cancer in the mother was significantly associated with an increased risk of breast cancer (HR 3.22, 95% CI 1.52-6.84). Analyses based on menopausal status at baseline indicated that height (≥160cm) and weight (≥65kg) were significantly associated with an increased risk of postmenopausal breast cancer, with HRs of 1.34 (95% CI 0.72-2.50) and 3.13 (95% CI 1.75-5.60), respectively. Risk associated with BMI significantly differs by menopausal status.Our findings suggest the important role of reproductive factors in the development of breast cancer in Japanese women; however, body mass index (BMI) may have different effects on breast cancer in Japanese women compared with western women.
Publisher	Lippincott Williams and Wilkins
Source Title	Medicine (United States)
Volume (Issue)	98(51)
Page	e18315
Date of Issued	2019-12
Language	English
Handle URL	https://hdl.handle.net/11094/78378
PISSN	00257974
eISSN	15365964
NCID	AA12542695
Relation.isIdenticalTo	DOI (Publisher Version) https://doi.org/10.1097/MD.0000000000018315
Relation.isIdenticalTo	PMID 31860982
Access Rights	open access
CopyRight	© 2019 the Author(s). Published by Wolters Kluwer Health, Inc. This article is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.
oaire:version	Version of Record
Category	学術雑誌論文 Journal Article

Resource Type	journal article
Local Type	Journal Article
DCMI Type	Text
DCTERMS.bibliographicCitation	Medicine (United States). 2019, 98(51), p. e18315
DC.title	Reproductive and lifestyle factors related to breast cancer among Japanese women: An observational cohort study
DC.creator	Liu, Rong
	Kitamura, Yuri
	Kitamura, Tetsuhisa
	Sobue, Tomotaka
	Sado, Junya
	Sugawara, Yumi
	Matsuo, Keitaro
	Nakayama, Tomio
	Tsuji, Ichiro
	Ito, Hidemi
	Suzuki, Takaichiro
	Katanoda, Kota
	Tominaga, Suketami
DC.publisher	Lippincott Williams and Wilkins
DC.language' scheme='DCTERMS.RFC1766	English
DC.type' scheme='DCTERMS.DCMIType	Text
DCTERMS.issued' scheme='DCTERMS.W3CDTF	2019-12
DC.identifier	https://doi.org/10.1097/MD.0000000000018315
DC.subject	body mass index
	breast cancer
	cohort
	epidemiology
	reproductive factors
DC.description	Liu R, Kitamura Y, Kitamura T, Sobue T, Sado J, Sugawara Y, Matsuo K, Nakayama T, Tsuji I, Ito H, Suzuki T, Katanoda K, Tominaga S. Reproductive and lifestyle factors related to breast cancer among Japanese women: An observational cohort study. Medicine 2019;98:51(e18315).
DCTERMS.abstract	The incidence of breast cancer among Japanese women is substantially increasing. This study evaluated the effects of reproductive and lifestyle factors with respect to breast cancer overall and separately among pre- and postmenopausal women using data from the Three-Prefecture Cohort Study of Japan.A total of 33,410 women aged 40 to 79 years completed a self-administered questionnaire, which included items about menstrual and reproductive history and other lifestyle factors. The follow-up period was from 1984 to 1992 in Miyagi and 1985 to 2000 in Aichi Prefectures. We used Cox proportional hazards regression models to estimate hazards ratios (HRs) and 95% confidence intervals (CIs) after adjusting for confounding factors.After 9.8 mean years of follow-up, 287 cases of breast cancer were recorded. In the overall analysis, later menarche (≥16 years) and parity were significantly associated with a decreased risk of breast cancer, with HRs of 0.69 (95% CI 0.48-0.99) and 0.72 (95% CI 0.52-0.99), respectively. Further, there was a significant decline in the risk of breast cancer with increasing number of birth among parous women (P for trend=.010). On the contrary, a family history of breast cancer in the mother was significantly associated with an increased risk of breast cancer (HR 3.22, 95% CI 1.52-6.84). Analyses based on menopausal status at baseline indicated that height (≥160cm) and weight (≥65kg) were significantly associated with an increased risk of postmenopausal breast cancer, with HRs of 1.34 (95% CI 0.72-2.50) and 3.13 (95% CI 1.75-5.60), respectively. Risk associated with BMI significantly differs by menopausal status.Our findings suggest the important role of reproductive factors in the development of breast cancer in Japanese women; however, body mass index (BMI) may have different effects on breast cancer in Japanese women compared with western women.
DC.rights	© 2019 the Author(s). Published by Wolters Kluwer Health, Inc. This article is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.
DC.format	78378
citation_title	Reproductive and lifestyle factors related to breast cancer among Japanese women: An observational cohort study
citation_author	Liu, Rong
	Kitamura, Yuri
	Kitamura, Tetsuhisa
	Sobue, Tomotaka
	Sado, Junya
	Sugawara, Yumi
	Matsuo, Keitaro
	Nakayama, Tomio
	Tsuji, Ichiro
	Ito, Hidemi
	Suzuki, Takaichiro
	Katanoda, Kota
	Tominaga, Suketami
citation_publisher	Lippincott Williams and Wilkins
citation_language	English
citation_date	2019-12
citation_journal_title	Medicine (United States)
citation_volume	98
citation_issue	51
citation_firstpage	e18315
citation_doi	https://doi.org/10.1097/MD.0000000000018315
citation_pmid	31860982
citation_public_url	https://hdl.handle.net/11094/78378

Reproductive and lifestyle factors related to breast cancer among Japanese women: An observational cohort study

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