A prospective study of reproductive and menstrual factors and colon cancer risk in Japanese women: Findings from the JACC study

Koji Tamakoshi, Kenji Wakai, Masayo Kojima, Yoshiyuki Watanabe, Norihiko Hayakawa, Hideaki Toyoshima, Hiroshi Yatsuya, Takaaki Kondo, Shinkan Tokudome, Shuji Hashimoto, Koji Suzuki, Sadao Suzuki, Miyuki Kawado, Kotaro Ozasa, Yoshinori Ito, Akiko Tamakoshi, Mitsuru Mori, Yutaka Motohashi, Ichiro Tsuji, Yosikazu NakamuraHiroyasu Iso, Haruo Mikami, Yutaka Inaba, Yoshiharu Hoshiyama, Hiroshi Suzuki, Hiroyuki Shimizu, Shinkan Tokudeme, Shogo Kikuchi, Akio Koizumi, Takashi Kawamura, Tsuneharu Miki, Chigusa Date, Kiyomi Sakata, Takayuki Nose, Takesumi Yoshimura, Katsuhiro Fukuda, Naoyuki Okamoto, Hideo Shio, Yoshiyuki Ohno, Tomoyuki Kitagawa, Toshio Kuroki, Kazuo Tajima

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

The effects of reproductive factors on the etiology of colon cancer in Asian populations remain unexplored. So we examined 38,420 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 for Evaluation of Cancer Risk. During an average 7.6 years of follow-up, we documented 207 incident colon cancers. Multivariate analysis indicated that colon cancer risk was likely to be lower among parous women than among nulliparous. Women who had two abortions or more had a 72% higher risk of developing colon cancer [relative risk (RR) 1.72; 95% confidence interval (CI) 1.16-2.55; trend P<0.01] compared with women who never had an abortion. The RR of colon cancer among postmenopausal women significantly decreased with increasing age at menarche (trend P=0.01). No apparent association between colon cancer and gravida, age at first birth, age at menopause, or duration of menstruation was seen. These prospective data support the hypothesis that female reproductive events modify colon cancer risk, and suggest that reproductive factors, particularly age at menarche and having an abortion, may be of importance in the etiology of colon cancer among Japanese women.

Original languageEnglish
Pages (from-to)602-607
Number of pages6
JournalCancer science
Volume95
Issue number7
DOIs
Publication statusPublished - 01-07-2004

All Science Journal Classification (ASJC) codes

  • Oncology
  • Cancer Research

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    Tamakoshi, K., Wakai, K., Kojima, M., Watanabe, Y., Hayakawa, N., Toyoshima, H., Yatsuya, H., Kondo, T., Tokudome, S., Hashimoto, S., Suzuki, K., Suzuki, S., Kawado, M., Ozasa, K., Ito, Y., Tamakoshi, A., Mori, M., Motohashi, Y., Tsuji, I., ... Tajima, K. (2004). A prospective study of reproductive and menstrual factors and colon cancer risk in Japanese women: Findings from the JACC study. Cancer science, 95(7), 602-607. https://doi.org/10.1111/j.1349-7006.2004.tb02494.x