Biological Sciences Division
Published September 5, 2023 | Version v1
Journal article Open

Reproductive Factors and Endometrial Cancer Risk Among Women

Creators

  • 1. National Cancer Center Institute for Cancer Control
  • 2. National Institutes of Biomedical Innovation
  • 3. National Center for Global Health and Medicine
  • 4. University of Sydney
  • 5. Seoul National University
  • 6. Hokkaido University
  • 7. National University of Singapore
  • 8. Radiation Effects Research Foundation
  • 9. Tohoku University
  • 10. National Cancer Center
  • 11. Gifu University
  • 12. Chonnam National University
  • 13. Vanderbilt University
  • 14. Shanghai Cancer Institute
  • 15. University of Pittsburgh
  • 16. University of Chicago

Description

Importance: Despite evidence of an association between reproductive factors and endometrial cancer risk, prospective studies have been conducted mainly in non-Asian countries.

Objective: To assess the association between reproductive factors, such as number of deliveries, age at menarche, or menopause, and endometrial cancer risk.

Design, Setting, and Participants: This cohort study used pooled individual data from 13 prospective cohort studies conducted between 1963 and 2014 in the Asia Cohort Consortium. Participants were Asian women. Data analysis was conducted from September 2019 to April 2023. Exposures: Reproductive factors were assessed using a questionnaire in each cohort.

Main Outcomes and Measures: The main outcome was time to incidence of endometrial cancer. A Cox proportional hazards model was used to calculate hazard ratios (HRs) and 95% CIs.

Results: A total of 1005 endometrial cancer cases were detected among 332 625 women (mean [SD] age, 54.3 [10.4] years) during a mean (SD) of 16.5 (6.4) years of follow-up. Increasing number of deliveries was associated with a decreased endometrial cancer risk in a dose-response manner (≥5 deliveries vs nulliparous [reference]: HR, 0.37; 95% CI, 0.26-0.53; P for trend < .001). Compared with menarche at younger than 13 years, menarche at 17 years or older had an HR of 0.64 (95% CI, 0.48-0.86; P for trend < .001). Late menopause (age ≥55 years) showed an HR of 2.84 (95% CI, 1.78-4.55; P for trend < .001) compared with the youngest age category for menopause (<45 years). Age at first delivery, hormone therapy, and breastfeeding were not associated with endometrial cancer risk.

Conclusions and Relevance: This large pooled study of individual participant data found that late menarche, early menopause, and a higher number of deliveries were significantly associated with a lower risk of endometrial cancer. These convincing results from Asian prospective studies add to the growing body of evidence for the association between reproductive factors and endometrial cancer.

Notes

Due to the large number of authors, only the first 20 and the University of Chicago authors are included on the above author list. Please download the article for the complete list of authors.

Data availability

See Supplement 2.

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Additional details

Identifiers

DOI
10.1001/jamanetworkopen.2023.32296
Other
oai:uchicago.tind.io:11245

Funding

National Cancer Institute
R37 CA070867
National Cancer Institute
UM1 CA182910
Japan Public Health Center
National Cancer Center
Research and Development Fund
National Cancer Center
Research and Development Fund
National Cancer Center
Research and Development Fund
Ministry of Health, Labour and Welfare of Japan
grant-in-aid for Cancer Research
Ministry of Health, Labour and Welfare, Japan
grants for health service and comprehensive research on cardiovascular and lifestyle related diseases
Ministry of Education, Culture, Sports, Science and Technology, Japan
grant for scientific research
Ministry of Science, ICT and Future Planning
2016R1A2B4014552
National Cancer Center
1510040
National Cancer Center
1810090
National Cancer Center
1910330
National Cancer Institute
R01CA144034
National Cancer Institute
UM1CA182876

UChicago Information

Division(s)
Biological Sciences Division
Department(s)
Public Health Sciences