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Article first published online: 20 DEC 2012
Copyright © 2012 American Cancer Society
Volume 119, Issue 7, pages 1393–1401, 1 April 2013
How to Cite
Schonfeld, S. J., Hartge, P., Pfeiffer, R. M., Freedman, D. M., Greenlee, R. T., Linet, M. S., Park, Y., Schairer, C., Visvanathan, K. and Lacey, J. V. (2013), An aggregated analysis of hormonal factors and endometrial cancer risk by parity. Cancer, 119: 1393–1401. doi: 10.1002/cncr.27909
For the National Institutes of Health-AARP (NIH-AARP) Diet and Health Study: Cancer incidence data from the Atlanta metropolitan area were collected by the Georgia Center for Cancer Statistics, Department of Epidemiology, Rollins School of Public Health, Emory University. Cancer incidence data from California were collected by the California Department of Health Services, Cancer Surveillance Section. Cancer incidence data from the Detroit metropolitan area were collected by the Michigan Cancer Surveillance Program, Community Health Administration, State of Michigan. The Florida cancer incidence data used in this report were collected by the Florida Cancer Data System under contract to the Department of Health (the views expressed herein are solely those of the authors and do not necessarily reflect those of the contractor or Department of Health). Cancer incidence data from Louisiana were collected by the Louisiana Tumor Registry, Louisiana State University Medical Center in New Orleans. Cancer incidence data from New Jersey were collected by the New Jersey State Cancer Registry, Cancer Epidemiology Services, New Jersey State Department of Health and Senior Services. Cancer incidence data from North Carolina were collected by the North Carolina Central Cancer Registry. Cancer incidence data from Pennsylvania were supplied by the Division of Health Statistics and Research, Pennsylvania Department of Health (the Pennsylvania Department of Health specifically disclaims responsibility for any analyses, interpretations, or conclusions). Cancer incidence data from Arizona were collected by the Arizona Cancer Registry, Division of Public Health Services, Arizona Department of Health Services. Cancer incidence data from Texas were collected by the Texas Cancer Registry, Cancer Epidemiology and Surveillance Branch, Texas Department of State Health Services. Cancer incidence data from Nevada were collected by the Nevada Central Cancer Registry, Center for Health Data and Research, Bureau of Health Planning and Statistics, State Health Division, State of Nevada Department of Health and Human Services.
For the Breast Cancer Detection Demonstration Project Follow-up Study: We are grateful to the study participants. We thank Dave Campbell and Leslie Carroll at Information Management Services for data management support.
For the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial: We thank Drs. Christine Berg and Philip Prorok, Division of Cancer Prevention, National Cancer Institute; the Screening Center investigators and staff of the PLCO Cancer Screening Trial; Mr. Tom Riley and staff at Information Management Services, Inc.; and Ms. Barbara O'Brien and staff at Westat, Inc. Most important, we acknowledge the study participants for their contributions to making this study possible.
For the US Radiologic Technologists (USRT) Study: We are grateful to the radiologic technologists who participated in the USRT Study; Jerry Reid of the American Registry of Radiologic Technologists for continued support of the study; Diane Kampa, Allison Iwan, and Richard Hoffbeck of the University of Minnesota for study coordination, data collection, and data management; and Jeremy Miller of Information Management Services for biomedical computing support.
- Issue published online: 18 MAR 2013
- Article first published online: 20 DEC 2012
- Manuscript Accepted: 23 OCT 2012
- Manuscript Revised: 16 OCT 2012
- Manuscript Received: 15 AUG 2012
- endometrial cancer;
- reproductive history;
- oral contraceptives;
Nulliparity is associated with an increased risk of endometrial cancer. It is less clear whether nulliparity modifies the association between other established hormone-related risk factors. The proportion of nulliparous women has increased since the mid-1970s, but most individual studies to date have been too small to test the hypothesis that endometrial cancer risk factors may be associated more strongly with risk among nulliparous women compared with parous women.
Data were aggregated on 26,936 postmenopausal, Caucasian, nulliparous women (360 endometrial cancers) and 146,583 postmenopausal, Caucasian, parous women (1378 endometrial cancers) from 4 US prospective studies (1979-2006). Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated in stratified analyses.
The risk of endometrial cancer was higher among nulliparous women than among parous women, as expected (nulliparous vs parous: HR, 1.42; 95% CI, 1.26-1.60). Stratified associations between endometrial cancer and hormone-related risk factors did not differ between nulliparous versus parous women: For both groups, oral contraceptives and earlier menopause were associated with reduced risk. The highest HRs were for obesity: A body mass index ≥30 kg/m2 (vs <25 kg/m2) increased the risk of endometrial cancer 3-fold among nulliparous women (HR, 3.04; 95% CI, 2.34-3.94) and parous women (HR, 2.88; 95% CI, 2.52-3.29).
The results from this large, pooled analysis of data from 4 large prospective studies suggested that nulliparity does not modify the risks of endometrial cancer associated with established hormone-related risk factors. Cancer 2013. © 2012 American Cancer Society.