Back to Annual Meeting Page		American Public Health Association 133rd Annual Meeting & Exposition December 10-14, 2005 Philadelphia, PA

Abstract #113337

Maura K. Whiteman, PhD and Polly A. Marchbanks, PhD. Division of Reproductive Health, Centers for Disease Control and Prevention, 4770 Buford Hwy NE, Mailstop K-34, Atlanta, GA 30341, 770-488-6293, acq5@cdc.gov

Previous studies suggest that reproductive history may be associated with endometrial cancer risk. We used data from a population-based case-control study (the Cancer and Steroid Hormone Study) to further characterize this relationship. Cases (n=437) were women newly diagnosed with endometrial cancer at ages 20–54. Women in the same age range were selected as controls using random-digit dialing (n=3165). Odds ratios (ORs) and 95% confidence intervals (95% CIs) were obtained from logistic regression adjusted for age and known risk factors for endometrial cancer. Compared to parous women, nulliparous women were at increased risk for endometrial cancer (OR, 2.6; 95% CI=1.9–3.7). Among parous women, age at last birth was inversely associated with endometrial cancer risk. Women aged ³35 at their last birth were at a decreased risk compared to women aged £24 at their last birth (OR, 0.5; 95% CI=0.3–0.8). Women aged 30–34 (OR, 0.8; 95% CI=0.5–1.2) and women aged 25–29 (OR, 0.8; 95% CI=0.6–1.2) were also at a somewhat lower risk than women aged £24 at their last birth (P for trend<0.01). Our results suggest that an older age at last birth is associated with a lower risk for endometrial cancer. This finding may result from a lower exposure to unopposed estrogen in women who have ovulatory cycles and can conceive at older ages. Alternatively it may involve shedding of the endometrium at delivery, which is more likely to contain pre-malignant or malignant cells as age increases.

Learning Objectives:

• At the conclusion of the presentation, the participant should be able to describe the relationship between reproductive history and the risk of endometrial cancer.

Keywords: Cancer, Reproductive Health

Presenting author's disclosure statement:

I wish to disclose that I have NO financial interests or other relationship with the manufactures of commercial products, suppliers of commercial services or commercial supporters.