Abstract 7384: Population attributable fraction of cancer incidence obesity and physical inactivity, in 2020 in the Republic of Korea

Abstract Abstract Purpose: Cancer is the leading cause of death in Korea. This study aimed to analyze the impact of two major risk factors, obesity and physical inactivity, on cancer incidence and to estimate the population attributable fraction (PAF) for cancers attributable to these factors in Korea as of 2020. Materials and Methods: For obesity-related cancers, 13 types of cancers (e.g., pharyngeal cancer, gastric cancer, pancreatic cancer, liver cancer) were selected based on the World Cancer Research Fund (WCRF) recommendation. Obesity was categorized using BMI as follows: 16.0 ≤ BMI < 18.5 (underweight), 18.5 ≤ BMI < 23.0 (normal weight; reference), 23.0 ≤ BMI < 25.0 (overweight ), 25.0 ≤ BMI < 30.0 (obesity), and BMI ≥ 30.0 (severe obesity). Physical inactivity was defined as having activities less than 600 MET·min/week. Exposure prevalence for obesity and physical inactivity in 2005 was derived from the Korea National Health and Nutrition Examination Survey (KNHANES) assuming 15 years of latency. Relative risks (RR) for cancer types were derived from meta-analyses of relative risks (RR) estimated from the four Korean cohort studies, including the Korean Genome and Epidemiology Study (KoGES), KNHANES, the health examination data from National Health Insurance Service (NHIS), and the Korean Cancer Prevention Study-II (KCPS-II) using Cox proportional hazards models. Confounding variables such as age, smoking status, alcohol consumption, and BMI were adjusted The PAF for each cancer type and overall cancer incidence was calculated using Levin’s formula. Results: For obesity-related cancers, the PAF for overall cancer incidence was 2.35% (5, 794 cases attributed to obesity in 2020) for the total population, 2.26% (2, 935 cases) for men, and 2.45% (2, 859 cases) for women. Among specific cancers, the highest PAFs were observed for kidney cancer (21.09%, men), pharyngeal cancer (27.07%, men), and endometrial cancer (29.38%, women). For physical inactivity, the PAF for overall cancer incidence was 0.39% (464 cases) for the total population, 0.47% (78 cases) for men, and 0.97% (387 cases) for women. Among cancer types, colorectal cancer showed the highest PAF (0.50%, 399 cases) for the total population, while breast cancer in women accounted for 65 cases (PAF 0.26%). Conclusion: Obesity and physical inactivity significantly contribute to cancer incidence in Korea, particularly for cancers such as kidney, endometrial, colorectal, and breast cancer. These findings underscore the need for targeted public health strategies to manage obesity and promote physical activity as part of comprehensive cancer prevention efforts. Further research should focus on refining risk estimates and exploring additional environmental and genetic factors affecting cancer incidence. Citation Format: SuJung Byoun. Population attributable fraction of cancer incidence obesity and physical inactivity, in 2020 in the Republic of Korea [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 7384.