Impact of menstrual and reproductive factors on breast cancer risk in Japan: Results of the JACC study

Koji Tamakoshi, Hiroshi Yatsuya, Kenji Wakai, Sadao Suzuki, Kazuko Nishio, Yingsong Lin, Yoshimitsu Niwa, Takaaki Kondo, Akio Yamamoto, Shinkan Tokudome, Hideaki Toyoshima, Akiko Tamakoshi, Mitsuru Mori, Yutaka Motohashi, Ichiro Tsuji, Yosikazu Nakamura, Hiroyasu Iso, Haruo Mikami, Yutaka Inaba, Yoshiharu HoshiyamaHiroshi Suzuki, Hiroyuki Shimizu, Yoshinori Ito, Shuji Hashimoto, Shogo Kikuchi, Akio Koizumi, Takashi Kawamura, Yoshiyuki Watanabe, Tsuneharu Miki, Chigusa Date, Kiyomi Sakata, Takayuki Nose, Norihiko Hayakawa, Takesumi Yoshimura, Akira Shibata, Naoyuki Okamoto, Hideo Shio, Yoshiyuki Ohno, Tomoyuki Kitagawa, Toshio Kuroki, Kazuo Tajima, Takashi Shimamoto, Heizo Tanaka, Shigeru Hisamichi, Masahiro Nakao, Takaichiro Suzuki, Tsutomu Hashimoto, Teruo Ishibashi, Katsuhiro Fukuda

Research output: Contribution to journalArticle

43 Citations (Scopus)

Abstract

The incidence of breast cancer among Japanese women, a traditionally low-risk population, has increased substantially. To evaluate the association of reproductive factors with breast cancer risk, we examined 38 159 Japanese women, aged 40-79 years, who responded to a questionnaire on reproductive and other lifestyle factors from 1988 to 1990 in the Japan Collaborative Cohort Study. During an average 7.6 years of follow-up, we documented 151 incidents of breast cancers. Cox proportional hazards modeling was employed to estimate relative risks (RR) and 95% confidence intervals (CI). There was a significant decline in the risk of breast cancer with increasing parity among parous women (trend P = 0.01). Women with four or more parities had a 69% lower risk than uniparous women, a reduced risk was also evident among menopausal women. Breast cancer risk tended to rise with increasing age at first delivery (trend P = 0.05), the association being very apparent among menopausal women (trend P = 0.02). Compared to the women who had their first delivery before age 25, those who delayed this event until after age 34 had an RR of 2.12 (95% CI: 0.72-6.21) and 3.33 (1.07-10.3) among the overall subjects and the menopausal, respectively. There was no apparent association of breast cancer risk with age at menarche or menopause. Our study concerning reproductive risk factors suggests that breast cancer in Japan is similar to that in Western countries, and that reproductive factors, particularly the number of parity and age at first delivery, might be important in the etiology of breast cancer among Japanese women.

Original languageEnglish
Pages (from-to)57-62
Number of pages6
JournalCancer science
Volume96
Issue number1
DOIs
Publication statusPublished - 01-01-2005

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Japan
Breast Neoplasms
Parity
Confidence Intervals
Menarche
Menopause
Life Style
Cohort Studies
Incidence
Population

All Science Journal Classification (ASJC) codes

  • Oncology
  • Cancer Research

Cite this

Tamakoshi, Koji ; Yatsuya, Hiroshi ; Wakai, Kenji ; Suzuki, Sadao ; Nishio, Kazuko ; Lin, Yingsong ; Niwa, Yoshimitsu ; Kondo, Takaaki ; Yamamoto, Akio ; Tokudome, Shinkan ; Toyoshima, Hideaki ; Tamakoshi, Akiko ; Mori, Mitsuru ; Motohashi, Yutaka ; Tsuji, Ichiro ; Nakamura, Yosikazu ; Iso, Hiroyasu ; Mikami, Haruo ; Inaba, Yutaka ; Hoshiyama, Yoshiharu ; Suzuki, Hiroshi ; Shimizu, Hiroyuki ; Ito, Yoshinori ; Hashimoto, Shuji ; Kikuchi, Shogo ; Koizumi, Akio ; Kawamura, Takashi ; Watanabe, Yoshiyuki ; Miki, Tsuneharu ; Date, Chigusa ; Sakata, Kiyomi ; Nose, Takayuki ; Hayakawa, Norihiko ; Yoshimura, Takesumi ; Shibata, Akira ; Okamoto, Naoyuki ; Shio, Hideo ; Ohno, Yoshiyuki ; Kitagawa, Tomoyuki ; Kuroki, Toshio ; Tajima, Kazuo ; Shimamoto, Takashi ; Tanaka, Heizo ; Hisamichi, Shigeru ; Nakao, Masahiro ; Suzuki, Takaichiro ; Hashimoto, Tsutomu ; Ishibashi, Teruo ; Fukuda, Katsuhiro. / Impact of menstrual and reproductive factors on breast cancer risk in Japan : Results of the JACC study. In: Cancer science. 2005 ; Vol. 96, No. 1. pp. 57-62.
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abstract = "The incidence of breast cancer among Japanese women, a traditionally low-risk population, has increased substantially. To evaluate the association of reproductive factors with breast cancer risk, we examined 38 159 Japanese women, aged 40-79 years, who responded to a questionnaire on reproductive and other lifestyle factors from 1988 to 1990 in the Japan Collaborative Cohort Study. During an average 7.6 years of follow-up, we documented 151 incidents of breast cancers. Cox proportional hazards modeling was employed to estimate relative risks (RR) and 95{\%} confidence intervals (CI). There was a significant decline in the risk of breast cancer with increasing parity among parous women (trend P = 0.01). Women with four or more parities had a 69{\%} lower risk than uniparous women, a reduced risk was also evident among menopausal women. Breast cancer risk tended to rise with increasing age at first delivery (trend P = 0.05), the association being very apparent among menopausal women (trend P = 0.02). Compared to the women who had their first delivery before age 25, those who delayed this event until after age 34 had an RR of 2.12 (95{\%} CI: 0.72-6.21) and 3.33 (1.07-10.3) among the overall subjects and the menopausal, respectively. There was no apparent association of breast cancer risk with age at menarche or menopause. Our study concerning reproductive risk factors suggests that breast cancer in Japan is similar to that in Western countries, and that reproductive factors, particularly the number of parity and age at first delivery, might be important in the etiology of breast cancer among Japanese women.",
author = "Koji Tamakoshi and Hiroshi Yatsuya and Kenji Wakai and Sadao Suzuki and Kazuko Nishio and Yingsong Lin and Yoshimitsu Niwa and Takaaki Kondo and Akio Yamamoto and Shinkan Tokudome and Hideaki Toyoshima and Akiko Tamakoshi and Mitsuru Mori and Yutaka Motohashi and Ichiro Tsuji and Yosikazu Nakamura and Hiroyasu Iso and Haruo Mikami and Yutaka Inaba and Yoshiharu Hoshiyama and Hiroshi Suzuki and Hiroyuki Shimizu and Yoshinori Ito and Shuji Hashimoto and Shogo Kikuchi and Akio Koizumi and Takashi Kawamura and Yoshiyuki Watanabe and Tsuneharu Miki and Chigusa Date and Kiyomi Sakata and Takayuki Nose and Norihiko Hayakawa and Takesumi Yoshimura and Akira Shibata and Naoyuki Okamoto and Hideo Shio and Yoshiyuki Ohno and Tomoyuki Kitagawa and Toshio Kuroki and Kazuo Tajima and Takashi Shimamoto and Heizo Tanaka and Shigeru Hisamichi and Masahiro Nakao and Takaichiro Suzuki and Tsutomu Hashimoto and Teruo Ishibashi and Katsuhiro Fukuda",
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Tamakoshi, K, Yatsuya, H, Wakai, K, Suzuki, S, Nishio, K, Lin, Y, Niwa, Y, Kondo, T, Yamamoto, A, Tokudome, S, Toyoshima, H, Tamakoshi, A, Mori, M, Motohashi, Y, Tsuji, I, Nakamura, Y, Iso, H, Mikami, H, Inaba, Y, Hoshiyama, Y, Suzuki, H, Shimizu, H, Ito, Y, Hashimoto, S, Kikuchi, S, Koizumi, A, Kawamura, T, Watanabe, Y, Miki, T, Date, C, Sakata, K, Nose, T, Hayakawa, N, Yoshimura, T, Shibata, A, Okamoto, N, Shio, H, Ohno, Y, Kitagawa, T, Kuroki, T, Tajima, K, Shimamoto, T, Tanaka, H, Hisamichi, S, Nakao, M, Suzuki, T, Hashimoto, T, Ishibashi, T & Fukuda, K 2005, 'Impact of menstrual and reproductive factors on breast cancer risk in Japan: Results of the JACC study', Cancer science, vol. 96, no. 1, pp. 57-62. https://doi.org/10.1111/j.1349-7006.2005.00010.x

Impact of menstrual and reproductive factors on breast cancer risk in Japan : Results of the JACC study. / Tamakoshi, Koji; Yatsuya, Hiroshi; Wakai, Kenji; Suzuki, Sadao; Nishio, Kazuko; Lin, Yingsong; Niwa, Yoshimitsu; Kondo, Takaaki; Yamamoto, Akio; Tokudome, Shinkan; Toyoshima, Hideaki; Tamakoshi, Akiko; Mori, Mitsuru; Motohashi, Yutaka; Tsuji, Ichiro; Nakamura, Yosikazu; Iso, Hiroyasu; Mikami, Haruo; Inaba, Yutaka; Hoshiyama, Yoshiharu; Suzuki, Hiroshi; Shimizu, Hiroyuki; Ito, Yoshinori; Hashimoto, Shuji; Kikuchi, Shogo; Koizumi, Akio; Kawamura, Takashi; Watanabe, Yoshiyuki; Miki, Tsuneharu; Date, Chigusa; Sakata, Kiyomi; Nose, Takayuki; Hayakawa, Norihiko; Yoshimura, Takesumi; Shibata, Akira; Okamoto, Naoyuki; Shio, Hideo; Ohno, Yoshiyuki; Kitagawa, Tomoyuki; Kuroki, Toshio; Tajima, Kazuo; Shimamoto, Takashi; Tanaka, Heizo; Hisamichi, Shigeru; Nakao, Masahiro; Suzuki, Takaichiro; Hashimoto, Tsutomu; Ishibashi, Teruo; Fukuda, Katsuhiro.

In: Cancer science, Vol. 96, No. 1, 01.01.2005, p. 57-62.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Impact of menstrual and reproductive factors on breast cancer risk in Japan

T2 - Results of the JACC study

AU - Tamakoshi, Koji

AU - Yatsuya, Hiroshi

AU - Wakai, Kenji

AU - Suzuki, Sadao

AU - Nishio, Kazuko

AU - Lin, Yingsong

AU - Niwa, Yoshimitsu

AU - Kondo, Takaaki

AU - Yamamoto, Akio

AU - Tokudome, Shinkan

AU - Toyoshima, Hideaki

AU - Tamakoshi, Akiko

AU - Mori, Mitsuru

AU - Motohashi, Yutaka

AU - Tsuji, Ichiro

AU - Nakamura, Yosikazu

AU - Iso, Hiroyasu

AU - Mikami, Haruo

AU - Inaba, Yutaka

AU - Hoshiyama, Yoshiharu

AU - Suzuki, Hiroshi

AU - Shimizu, Hiroyuki

AU - Ito, Yoshinori

AU - Hashimoto, Shuji

AU - Kikuchi, Shogo

AU - Koizumi, Akio

AU - Kawamura, Takashi

AU - Watanabe, Yoshiyuki

AU - Miki, Tsuneharu

AU - Date, Chigusa

AU - Sakata, Kiyomi

AU - Nose, Takayuki

AU - Hayakawa, Norihiko

AU - Yoshimura, Takesumi

AU - Shibata, Akira

AU - Okamoto, Naoyuki

AU - Shio, Hideo

AU - Ohno, Yoshiyuki

AU - Kitagawa, Tomoyuki

AU - Kuroki, Toshio

AU - Tajima, Kazuo

AU - Shimamoto, Takashi

AU - Tanaka, Heizo

AU - Hisamichi, Shigeru

AU - Nakao, Masahiro

AU - Suzuki, Takaichiro

AU - Hashimoto, Tsutomu

AU - Ishibashi, Teruo

AU - Fukuda, Katsuhiro

PY - 2005/1/1

Y1 - 2005/1/1

N2 - The incidence of breast cancer among Japanese women, a traditionally low-risk population, has increased substantially. To evaluate the association of reproductive factors with breast cancer risk, we examined 38 159 Japanese women, aged 40-79 years, who responded to a questionnaire on reproductive and other lifestyle factors from 1988 to 1990 in the Japan Collaborative Cohort Study. During an average 7.6 years of follow-up, we documented 151 incidents of breast cancers. Cox proportional hazards modeling was employed to estimate relative risks (RR) and 95% confidence intervals (CI). There was a significant decline in the risk of breast cancer with increasing parity among parous women (trend P = 0.01). Women with four or more parities had a 69% lower risk than uniparous women, a reduced risk was also evident among menopausal women. Breast cancer risk tended to rise with increasing age at first delivery (trend P = 0.05), the association being very apparent among menopausal women (trend P = 0.02). Compared to the women who had their first delivery before age 25, those who delayed this event until after age 34 had an RR of 2.12 (95% CI: 0.72-6.21) and 3.33 (1.07-10.3) among the overall subjects and the menopausal, respectively. There was no apparent association of breast cancer risk with age at menarche or menopause. Our study concerning reproductive risk factors suggests that breast cancer in Japan is similar to that in Western countries, and that reproductive factors, particularly the number of parity and age at first delivery, might be important in the etiology of breast cancer among Japanese women.

AB - The incidence of breast cancer among Japanese women, a traditionally low-risk population, has increased substantially. To evaluate the association of reproductive factors with breast cancer risk, we examined 38 159 Japanese women, aged 40-79 years, who responded to a questionnaire on reproductive and other lifestyle factors from 1988 to 1990 in the Japan Collaborative Cohort Study. During an average 7.6 years of follow-up, we documented 151 incidents of breast cancers. Cox proportional hazards modeling was employed to estimate relative risks (RR) and 95% confidence intervals (CI). There was a significant decline in the risk of breast cancer with increasing parity among parous women (trend P = 0.01). Women with four or more parities had a 69% lower risk than uniparous women, a reduced risk was also evident among menopausal women. Breast cancer risk tended to rise with increasing age at first delivery (trend P = 0.05), the association being very apparent among menopausal women (trend P = 0.02). Compared to the women who had their first delivery before age 25, those who delayed this event until after age 34 had an RR of 2.12 (95% CI: 0.72-6.21) and 3.33 (1.07-10.3) among the overall subjects and the menopausal, respectively. There was no apparent association of breast cancer risk with age at menarche or menopause. Our study concerning reproductive risk factors suggests that breast cancer in Japan is similar to that in Western countries, and that reproductive factors, particularly the number of parity and age at first delivery, might be important in the etiology of breast cancer among Japanese women.

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