O2-1.6 Childhood, Early Adulthood, and Middle Age Adiposity and Risk of Postmenopausal Endometrial Cancer

Abstract

<h3>Background</h3> Middle age obesity is a common risk factor of postmenopausal endometrial cancer and breast cancer. Recent studies suggest that childhood and early adulthood obesity might be independent protective factors against breast cancer, while this effect has not been well understood in endometrial cancer. <h3>Methods</h3> This analysis is based on 378 614 postmenopausal British women in the Million Women Study who reported validated information of their body shape at 10 years old, clothes size at 20 years old, current body mass index, and other information in middle age (mean age 58 years), and follow-up by the National Health Service Central Registers for 6.05 years on average. Women with recent use of hormone replacement therapy were excluded. Cox regression is used to estimate the risk of endometrial cancer. <h3>Results</h3> There are significant associations between body size at 10, 20 and middle age. Having a larger body size at 10 years old, at 20 years old or in middle age is each associated with a higher risk of endometrial cancer in middle age. However, the risks associated with body size at 10 and 20 years old are attenuated after adjustment for or stratification with middle-aged body size. <h3>Conclusion</h3> The association of postmenopausal endometrial cancer with childhood or early adulthood obesity is largely explained through body size in middle age. The independent effect of childhood or early adulthood body size on postmenopausal endometrial cancer is not seen.