OBJECTIVE: To examine the risk for endometrial cancer among overweight women using the World Health Organization's clinical definitions of obesity based on body mass index (BMI).
METHODS: Conducted in the early 1980s, the Cancer and Steroid Hormone study was a multicenter, population-based, case–control study of breast, ovarian, and endometrial cancers among women aged 20–54 years. Participants for the case group (n=421) were identified through cancer registries and had histologically confirmed endometrial cancer. Participants for the control group (n=3,159) were chosen by random-digit dialing methods in the same regions as those in the case group. Those in the case and control groups responded to the same questions during in-person interviews. Unconditional logistic regression was used to estimate adjusted odds ratios (ORs) and 95% confidence intervals (CIs).
RESULTS: The relationship between endometrial cancer and BMI (calculated as weight [kg]/[height (m)]2) was modified by age at last menstrual period (LMP). Of women who were younger than 45 years at LMP, those with BMIs of at least 35.0 had a greater risk of endometrial cancer (56%, 30/54) than did those with normal BMIs (4%, 59/1,492, adjusted OR 21.7, 95% CI 11.3–41.7). Of women age 45 or older at LMP, those with BMIs of at least 35.0 also had a greater risk (40%, 24/60) than did those with normal BMIs (14%, 168/1,235, adjusted OR 3.7, 95% CI 2.0–6.6). Women younger than 45 years at LMP and those with BMIs of at least 25.0 at 18 years and as adults (25%, 31/123) had an approximately sixfold increased risk (adjusted OR 5.8, 95% CI 3.4–9.8) compared with those with normal BMIs at 18 and as adults (4%, 58/1,460).
CONCLUSION: Very obese women aged 20–54 years have an elevated endometrial cancer risk, which appears heightened by early menopause.
LEVEL OF EVIDENCE: II
Morbidly obese women are at markedly elevated risk for endometrial cancer before age 54.
From the 1Division of Cancer Prevention and Control, National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control and Prevention, Atlanta, Georgia; and the 2Department of Obstetrics and Gynecology, Emory University School of Medicine, Atlanta, Georgia.
See related articles on pages 7, 16, and 100.
The findings and conclusions in this manuscript are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention.
The Cancer and Steroid Hormone Study was supported by interagency agreement 3-Y01-HD-8-1037 between the Centers for Disease Control and Prevention and the Eunice Kennedy Shriver National Institute of Child Health and Human Development, with additional support from the National Cancer Institute.
Corresponding author: Cheryll C. Thomas, MSPH, Centers for Disease Control and Prevention, Division of Cancer Prevention and Control, Cancer Surveillance Branch, 4770 Buford Hwy NE, MS K-53, Atlanta, GA 30341; e-mail: CCThomas@cdc.gov.
Financial Disclosure The authors did not report any potential conflicts of interest.