Fractions and number of cancer cases attributable to excess body fat in South Korea

This is the authors' abstract. We don't add key points for this paper.

BACKGROUND: Excess body fat (EBF) is a major cancer risk factor, yet its impact in Asians remains underexplored. We estimated the population-attributable fraction (PAF) of EBF for various cancers in Korea, comparing estimates based on body mass index (BMI) and waist circumference (WC). METHODS: Relative risks were derived from Korean National Health Insurance Service data of 4 441 103 adults screened in 2012, with 242 243 cancer cases identified through 2020. PAFs were calculated by using 2022 national obesity prevalence and cancer registry data. Sensitivity analyses were conducted among never smokers. RESULTS: The PAFs for 13 established obesity-associated cancers reached 5.48% (BMI) and 7.65% (WC) in men, 5.48% (BMI) and 6.68% (WC) in women aged <50 years, and 6.86% (BMI) and 9.34% (WC) in women aged ≥50 years. This translates into 16 534.2 avoidable-cancer cases in 2022 via BMI and 22 486.9 via WC. In sensitivity analyses, positive associations between obesity and cancer risk were more pronounced among never smokers, suggesting that smoking may mask the true impact of EBF in the general population. CONCLUSION: EBF significantly contributes to the cancer burden in Korea. Using BMI as the sole measure may substantially underestimate this burden compared with WC, which captures visceral adiposity more effectively. Our findings emphasize the importance of abdominal obesity management and support evidence-based public health policies for cancer prevention in Asian populations.