Associations of Body Mass Index, Weight Change, Physical Activity, and Sedentary Behavior With Endometrial Cancer Risk Among Japanese Women: The Japan Collaborative Cohort Study

Hiromi Miyata,Akiko Tamakoshi,Hiroyasu Iso,Isao Muraki,Kokoro Shirai

doi:10.2188/jea.je20200145

Abstract

BackgroundThe impact of weight change, physical activity, and sedentary behavior on endometrial cancer risk among the Asian population is uncertain. We investigated the association of those factors with endometrial cancer risk among Japanese women with a low body mass index level.MethodsWe performed a large-scale nationwide cohort study consisting of 33,801 female participants aged 40–79 years. The Cox proportional hazards model was used to calculate the hazard ratios (HRs) and 95% confidence intervals (CIs) of incident endometrial cancer.ResultsThe mean body mass index of participants was 22.8 kg/m2. During a median follow-up of 14.8 years, 79 participants developed endometrial cancer. After adjustment for potential confounding factors, body mass index over 23.0 kg/m2 was linearly associated with the risk of endometrial cancer. The HR per 5 kg/m2 increase was 1.80 (95% CI, 1.28–2.54). Weight increment ≥+5 kg since age 20 was associated with an increased risk of endometrial cancer compared to a weight change of −5 to <+5 kg (multivariable HR 1.96; 95% CI, 1.12–3.40). Compared with females who were mainly sitting at the worksite, those who were mainly standing and moving were at lower risk; the multivariable HRs were 0.79 (95% CI, 0.39–1.59) and 0.46 (95% CI, 0.22–0.97), respectively (P for trend = 0.042). Hours of physical exercise, daily walking, and TV viewing were not associated with endometrial cancer risk.ConclusionsOverweight and weight gain were positively associated with the risk of endometrial cancer, while worksite physical activity was inversely associated with the risk.

Highlights

Endometrial cancer is the sixth most common type of cancer worldwide in women, following breast, colorectal, lung, cervical= uterine, and thyroid.[1]
The aim of this study was to determine whether body mass index (BMI), weight change, physical activity, and sedentary behavior were associated with endometrial cancer in Japanese participants aged 40–79 years
Multivariable hazard ratios (HRs) of endometrial cancer with reference to a baseline BMI of 18.5 to

Summary

Introduction

Endometrial cancer is the sixth most common type of cancer worldwide in women, following breast, colorectal, lung, cervical= uterine, and thyroid.[1]. Nulliparity, unopposed estrogen therapy, late menopause, tamoxifen therapy, and diabetes, and those associated with unopposed estrogen stimulation were associated with an increased risk of endometrial cancer,[4,5] whereas breastfeeding,[6] oral contraceptive use,[7] and physical activity[8] were associated with a decreased risk. These findings have come primarily from Western populations but not from Asian populations.[9,10,11] the generalization of such findings to other ethnic groups requires confirmation. We investigated the association of those factors with endometrial cancer risk among Japanese women with a low body mass index level

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