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Obstetrics and Gynecology International
Volume 2013 (2013), Article ID 743721, 10 pages
http://dx.doi.org/10.1155/2013/743721
Research Article

A Large Cohort Study of Hypothyroidism and Hyperthyroidism in Relation to Gynecologic Cancers

1Channing Division of Network Medicine, Brigham & Women's Hospital, Harvard Medical School, Boston, MA, USA
2Division of Gynecologic Oncology, University of Connecticut Health Center, 263 Farmington Avenue, MC1614, Farmington, CT 06034, USA
3Division of Epidemiology & Biostatistics, Department of Community Medicine and Health Care, University of Connecticut Health Center, Farmington, CT, USA
4Department of Epidemiology, Harvard School of Public Health, Boston, MA, USA
5Department of Biostatistics, Harvard School of Public Health, Boston, MA, USA
6Division of Endocrinology, Brigham & Women's Hospital, Harvard Medical School, Boston, MA, USA

Received 3 May 2013; Revised 23 June 2013; Accepted 24 June 2013

Academic Editor: Paulette Mhawech-Fauceglia

Copyright © 2013 Jae H. Kang et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Background. Thyroid status may influence tumorigenesis of gynecologic cancers, yet epidemiologic studies of this relationship are limited and inconsistent. Methods. We evaluated the association of self-reported history of physician-diagnosed hypothyroidism and hyperthyroidism with medical-record confirmed endometrial (EC; all invasive adenocarcinomas) and ovarian cancer (OC; epithelial ovarian or peritoneal cancers) in Nurses' Health Study (NHS) from 1976 to 2010 and NHSII from 1989 to 2011. Cox proportional hazard models were used to estimate multivariable rate ratios (RRs) and 95% confidence intervals based on pooled cohort data. Results. We confirmed 1314 incident cases of EC and 1150 cases of OC. Neither a history of hypothyroidism nor hyperthyroidism was significantly associated with risk of EC or OC. However, having a history of hypothyroidism for 8+ years (median) was nonsignificantly inversely associated with EC (RR = 0.81; 95% CI = 0.63–1.04; P-trend with history duration = 0.11) and OC (RR = 0.87, 95% CI = 0.66–1.15; P-trend = 0.13). Having a history of hyperthyroidism for 6+ years (median) was non-significantly positively associated with EC (RR = 1.69; 95% CI = 0.86–3.30; P-trend = 0.12) but not OC (RR = 1.12; 95% CI = 0.46–2.72; P-trend = 0.95). Conclusions. A history of hypothyroidism or hyperthyroidism was not significantly associated with risk of EC or OC.