OBJECTIVETo study the relationship between obesity at different ages and the risk of endometrial cancer in urban Shanghai, China.

METHODSIn a population-based case-control study conducted in urban Shanghai, in-person interviews and anthropometric measurements were completed for 497 women at age 30 to 69 and an equal number of controls frequency-matched to cases on age distribution. All cases were newly diagnosed with endometrial cancer from January 1, 1997 to June 30, 2000. Unconditional logistic regression model was employed to estimate the adjusted odds ratios (ORs) and 95% confidence intervals (CIs) of the obesity at different ages.

RESULTSAfter adjustment for some potential confounding variables, neither adolescent height nor weight was significantly related to endometrial cancer. Obesity in adulthood, except around 20 years old, was associated with elevated risks, with odds ratios for the highest versus lowest quartile of body mass index (BMI) being 1.5 (95% CI: 1.0 - 2.1), 1.7 (95% CI: 1.2 - 2.4), 1.9 (95% CI: 1.3 - 2.8) and 1.7 (95% CI: 1.0 - 2.7) at ages 30, 40, 50 and 60, respectively. Weight gain of more than 7.5 kg at different 10-year intervals in adulthood were associated with increased risk of endometrial cancer, whereas only weight gain more than 15% of initial weight from 40 to 50 years old significantly related to the risk. Only weight loss from ages 20 to 30 was inversely associated with endometrial cancer risk (OR = 0.4, 95% CI: 0.2 - 0.8). Current body weight, BMI and waist-to-hip ratio (WHR) were independent risk factors to endometrial cancer while standing height and sitting-to-standing height ratio were unrelated to the risk of endometrial cancer.

CONCLUSIONResults indicated that adolescent obesity was unrelated to endometrial cancer. General obesity in adulthood, as well as body fat distribution, were associated with the risk of endometrial cancer independently. Weight changes before and after age 30 had different effects on the risk of endometrial cancer.