Weight change and risk of endometrial cancer

Abstract

Background: Obesity is an established risk factor for endometrial cancer. Less well understood is the role of weight gain and weight change in determining risk. Methods: We analysed data from a population-based case-control study to evaluate the associations of body mass index (BMI), weight gain, and weight cycling with risk of endometrial cancer. Cases (n = 740) under age 80 with a new diagnosis of endometrial cancer were identified from Wisconsin's cancer registry. Controls (n = 2342) were randomly selected from driver's license lists and Medicare beneficiary files. Body size at three time points and other risk factor information were ascertained by interview in 1992-95. Results: Endometrial cases were more likely than controls to be nulliparous, have early ages at menarche and late ages at menopause, be diabetic, smoke cigarettes, and use post-menopausal hormones. After adjustment for these factors, increasing BMI was associated with increased risk (P-trend < 0.001); women in the top quartile of BMI (>29 kg/m2) had a 3-fold greater risk of endometrial cancer [95% confidence interval (95% CI) 2.4-4.2] compared with women in the lowest quartile (<23 kg/-m2). For each 5 kg weight gain, the odds ratio (OR) for endometrial cancer risk equalled 1.2 (95% CI 1.2-1.3). History of weight cycling modestly increased risk after adjustment for BMI and other factors (OR = 1.3; 95% CI 1.0-1.6). In addition, women who reported sustained weight loss had a reduced risk of endometrial cancer (OR = 0.7; 95% CI 0.6-0.9). Conclusions: These results suggest that weight gain and lack of weight stability are associated with risk of endometrial cancer. © The Author 2005; all rights reserved.