Population Attributable Fraction of Cancer Incidence Due to Dietary Factors in 2020 in the Republic of Korea

Objectives: In 2019, cancer was South Korea's leading cause of death (27.5%). Diet and nutrition are recognized as significant factors in cancer prevention. This study aims to estimate the population attributable fraction (PAF) of cancer incidence due to dietary factors in the Korean population. Methods: We selected dietary factors and cancer sites for PAF estimation based on the classification lists of the International Agency for Research on Cancer, considering sufficient/limited evidence in humans, and the lists from the World Cancer Research Fund and the American Institute for Cancer Research, which provide convincing/probable evidence in humans. PAF was calculated using Levin's formula, incorporating exposure prevalence and relative risk (RR). Exposure prevalence data were derived from the 2005 Korea National Health and Nutrition Examination Survey (KNHANES), assuming a 15-year latent period. We established minimum risk exposure levels for both inadequate and excessive intakes of selected dietary factors. The Cox proportional hazards model was employed to calculate RRs from four cohorts: the Korean Genome and Epidemiology Study, National Health Insurance Services, Korean Cancer Prevention Study-II, and KNHANES, each linked with the Korea Cancer Registry. Meta-analysis was performed on RRs, generating pooled RRs using a random-effects model. Results: PAFs for all cancer incidence due to dietary factors were 9.9% in men and 9.5% in women. For specific cancer sites, percentages varied, e.g., colorectal cancer in men and women was 21.1%, 40.1%, respectively. Specific dietary factors, such as insufficient whole grains (men 0.56%, women 0.72%), were associated with cancer incidence. Conclusions: From our estimates, around 10% of cancer incidence may be preventable through proper diet. Funding Sources: This work was supported by the National Cancer Center Grant (NCC-2210840) and National Research Foundation of Korea (2021R1A2C2008439).