title: Physical activity and risk of endometrial cancer in the Norwegian Women and Cancer (NOWAC) study.
abstract: Few studies have investigated the association between endometrial cancer and physical activity (PA) using repeated measures of PA and different subtypes of endometrial cancer. We aimed to investigate the association between endometrial cancer and PA level at two points in time in women with different body mass index (BMI) profiles, and to calculate the population attributable fraction (PAF) of endometrial cancer for low PA levels. We included 82,759 women with complete information on PA at baseline in the Norwegian Women and Cancer Study; 52,370 had follow-up information on PA. 687 endometrial cancer cases were identified. Multivariate cox proportional hazard models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI). The PAF indicated the proportion of endometrial cancer that could be avoided in the population if these women had a higher PA level. There was a statistically significant association between low PA levels at baseline and follow-up and endometrial cancer risk, with a dose-response trend (lowest PA level: HR = 1.60, 95% CI 1.16-2.20; highest PA level: HR = 0.73, 95% CI 0.45-1.16 compared to the median). Analyses that included follow-up measurements yielded similar results. 21.9% (95% CI 7.1-34.3) of endometrial cancers could be avoided if women with low PA levels (≤ 4 in a 1-10 degree self reported PA scale) increased their PA levels to 5-10. We found an inverse dose-response association between PA and endometrial cancer, independent of BMI. In this nationally representative cohort, 21.9% of endometrial cancers could potentially be avoided if PA levels increased to higher PA levels.
authors.affiliation: Department of Community Medicine, Faculty of Health Sciences, UiT, The Arctic University of Norway, Tromsø, Norway.
authors.forename: Kristin B
authors.initials: KB
authors.lastname: Borch
authors.affiliation: Department of Community Medicine, Faculty of Health Sciences, UiT, The Arctic University of Norway, Tromsø, Norway.|Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden.|Department of Research, Cancer Registry of Norway, Institute of Population-Based Cancer Research, Oslo, Norway.|Genetic Epidemiology Group, Folkhälsan Research Centre, Samfundet Folkhälsan, Helsinki, Finland.
authors.forename: Elisabete
authors.initials: E
authors.lastname: Weiderpass
authors.affiliation: Department of Community Medicine, Faculty of Health Sciences, UiT, The Arctic University of Norway, Tromsø, Norway.
authors.forename: Tonje
authors.initials: T
authors.lastname: Braaten
authors.affiliation: Department of Community Medicine, Faculty of Health Sciences, UiT, The Arctic University of Norway, Tromsø, Norway.
authors.forename: Mie
authors.initials: M
authors.lastname: Jareid
authors.affiliation: Department of Community Medicine, Faculty of Health Sciences, UiT, The Arctic University of Norway, Tromsø, Norway.
authors.forename: Oxana A
authors.initials: OA
authors.lastname: Gavrilyuk
authors.affiliation: Department of Community Medicine, Faculty of Health Sciences, UiT, The Arctic University of Norway, Tromsø, Norway.
authors.forename: Idlir
authors.initials: I
authors.lastname: Licaj
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D054242:Emigrants and Immigrants; D016889:Endometrial Neoplasms / Q000453:epidemiology* / Q000503:physiopathology; D015444:Exercise; D005260:Female; D006801:Humans; D008875:Middle Aged; D009043:Motor Activity; D009664:Norway / Q000453:epidemiology; D009765:Obesity / Q000453:epidemiology* / Q000503:physiopathology; D017698:Postmenopause / Q000502:physiology; D016016:Proportional Hazards Models; D012307:Risk Factors; D011795:Surveys and Questionnaires
keywords: endometrial cancer; physical activity; population attributable fraction; prospective study