Purpose: To develop the 2025 update to the Korean colorectal cancer (CRC) screening guidelines by systematically evaluating recent evidence, integrating domestic data, and addressing changes since the 2015 guideline revision, thereby providing an evidence-based standard for clinicians and policymakers. Methods: A multidisciplinary committee developed the guidelines using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) methodology. The process included formulation of three key questions addressing screening efficacy, diagnostic accuracy, and optimal screening age and interval. A systematic review of international guidelines and primary literature was conducted, yielding 327 eligible studies. In addition, a utility-based analysis using a Markov model was performed to determine optimal screening ages and intervals. Results: The evidence synthesis identified high-certainty evidence supporting the use of the fecal immunochemical test (FIT) for reducing CRC mortality and moderate-certainty evidence for colonoscopy. Evidence for computed tomographic colonography (CTC) and stool DNA testing was rated as very low certainty. Based on the evidence review and cost-utility analysis, the committee conditionally recommends CRC screening for asymptomatic, average-risk adults aged 45–74 years using either colonoscopy every 10 years or FIT every 1–2 years. CTC and stool DNA testing were not recommended owing to insufficient evidence. Conclusion The 2025 Korean Guidelines for Colorectal Cancer Screening present updated, evidence-based recommendations tailored to the domestic healthcare context. By conditionally endorsing both colonoscopy and FIT for individuals aged 45–74 years, these guidelines aim to improve population-level screening effectiveness and reduce the burden of CRC in South Korea.

This study aimed to determine the association between trajectories of obesity status and prediabetes reversion to normoglycemia or progression to diabetes. The study included 14,452 participants from the National Health Insurance Service-National Health Screening (NHIS-HEALS) cohort who continuously had prediabetes glycemic status during the index period (2002-2008), definedby their fasting plasma glucose. The exposure of the study was the trajectories of obesity (defined by body mass index ≥ 25 kg/m 2 ) generated using latent class growth analysis. The outcomes were reversion to normoglycemia or progression to diabetes, whichever occurred first during the follow-up period (2009-2016). The association between trajectories and changes in prediabetes status were examined using cause-specific hazard regression by obtaining the hazard ratio (HR) with a 95% CI. We identified three distinct trajectories which were “Stable obese”, “Stable non-obese” and “Obese to non-obese”. After a median follow-up of 2years, 51.99% of participants had their glycemic status back to normoglycemia and 32.17% developed diabetes. Compared with participants in the “Stable obese” group, those in “Stable non-obese” and “Obese to non-obese” groups were more likely to have reversion to normoglycemia (HR with a 95% CI = 1.30 [1.23-1.37] and 1.15 [1.07-1.24], respectively) and lower risk of developingdiabetes (0.78 [0.73-0.84] and 0.90 [0.82-0.98], respectively). The findings suggest that maintaining or achieving a non-obese sta-tus is linked to higher reversion to normoglycemia as well as lower risks of developing diabetes.

Background: Evaluate the impact of chest X-ray (CXR) screening on mortality and treatment adherence by comparing pulmonary tuberculosis (PTB) cases detected through screening and those routinely diagnosed at healthcare facilities. Methods: A retrospective analysis of 10% randomly sampled National Health Insurance Service claims data assessed PTB cases diagnosed during 2004–2020. Patients were categorized as ‘screening-detected (ACF, active case finding)’ or ‘routinely detected (PCF, passive case finding)’ based on CXR screening history. Cox proportional hazards model determined the association between screening and all-cause or tuberculosis (TB)-specific mortality. Treatment adherence was also measured. Results: Among 84,828 PTB patients, 18.76% were ACF (15,916), and 81.24% were PCF (68,912). ACF exhibited lower risks in all-cause mortality (adjusted hazard ratio [aHR], 0.70;95% confidence interval [CI], 0.67–0.73) and TB-specific mortality (aHR, 0.38; 95% CI, 0.32–0.46) compared to PCF. In the ACF group, 91.39% initiated anti-TB treatment, with 45.99% adherence. For PCF, 92.87% initiated treatment, and only 45.44% were adherent. Conclusion Individuals undergoing CXR screening have a lower risk of both all-cause and TB-specific mortality compared to PCF, but treatment adherence is similar between the two groups, emphasizing the need to improve the linkage between screening, diagnosis, and treatment for the screened population.

Background: The relationship between aspirin usage and the risk of colorectal cancer (CRC) among individuals with both hypertension (HTN) and diabetes mellitus (DM) remains unclear. This study aims to explore the impact of aspirin use on the site-specific CRC risk in patients with metabolic comorbidity. Methods: A case-control study was conducted among 1,331 CRC patients and 2,771 controls recruited from the Nation Cancer Center in Korea. Multinomial logistic regression analyses were used to calculate the odds ratios (ORs) and 95% confidence intervals (CIs) for the association between aspirin use, metabolic disease status, and site-specific CRC risk. Results: Among the 4,102 participants, 1,191 individuals had neither HTN nor DM, 2,044 were diagnosed with HTN, 203 with DM, and 664 presented with HTN and DM comorbidity.An increasing number of HTN and DM was associated with an increased risk of overall CRC (HTN or DM: OR, 1.70; 95% CI, 1.39–2.07; HTN and DM: OR, 8.43; 95% CI, 6.37–11.16), while aspirin use was associated with a decreased risk of overall CRC (OR, 0.31; 95% CI, 0.21–0.46).These results remained consistent across anatomical sites. Among individuals with HTN and DM comorbidity, aspirin use notably associated with lower risk of overall CRC (OR, 0.39; 95% CI, 0.21–0.72), proximal colon (OR, 0.32; 95% CI, 0.13–0.71) and rectal cancer (OR, 0.27;95% CI, 0.08–0.97), but not distal colon cancer (OR, 0.58; 95% CI, 0.27–1.24). Conclusion This study showed that aspirin use is negatively associated with overall and sitespecific CRC, even among individuals with HTN and DM comorbidity.

Background: Evaluate the impact of chest X-ray (CXR) screening on mortality and treatment adherence by comparing pulmonary tuberculosis (PTB) cases detected through screening and those routinely diagnosed at healthcare facilities. Methods: A retrospective analysis of 10% randomly sampled National Health Insurance Service claims data assessed PTB cases diagnosed during 2004–2020. Patients were categorized as ‘screening-detected (ACF, active case finding)’ or ‘routinely detected (PCF, passive case finding)’ based on CXR screening history. Cox proportional hazards model determined the association between screening and all-cause or tuberculosis (TB)-specific mortality. Treatment adherence was also measured. Results: Among 84,828 PTB patients, 18.76% were ACF (15,916), and 81.24% were PCF (68,912). ACF exhibited lower risks in all-cause mortality (adjusted hazard ratio [aHR], 0.70;95% confidence interval [CI], 0.67–0.73) and TB-specific mortality (aHR, 0.38; 95% CI, 0.32–0.46) compared to PCF. In the ACF group, 91.39% initiated anti-TB treatment, with 45.99% adherence. For PCF, 92.87% initiated treatment, and only 45.44% were adherent. Conclusion Individuals undergoing CXR screening have a lower risk of both all-cause and TB-specific mortality compared to PCF, but treatment adherence is similar between the two groups, emphasizing the need to improve the linkage between screening, diagnosis, and treatment for the screened population.

Background: Evaluate the impact of chest X-ray (CXR) screening on mortality and treatment adherence by comparing pulmonary tuberculosis (PTB) cases detected through screening and those routinely diagnosed at healthcare facilities. Methods: A retrospective analysis of 10% randomly sampled National Health Insurance Service claims data assessed PTB cases diagnosed during 2004–2020. Patients were categorized as ‘screening-detected (ACF, active case finding)’ or ‘routinely detected (PCF, passive case finding)’ based on CXR screening history. Cox proportional hazards model determined the association between screening and all-cause or tuberculosis (TB)-specific mortality. Treatment adherence was also measured. Results: Among 84,828 PTB patients, 18.76% were ACF (15,916), and 81.24% were PCF (68,912). ACF exhibited lower risks in all-cause mortality (adjusted hazard ratio [aHR], 0.70;95% confidence interval [CI], 0.67–0.73) and TB-specific mortality (aHR, 0.38; 95% CI, 0.32–0.46) compared to PCF. In the ACF group, 91.39% initiated anti-TB treatment, with 45.99% adherence. For PCF, 92.87% initiated treatment, and only 45.44% were adherent. Conclusion Individuals undergoing CXR screening have a lower risk of both all-cause and TB-specific mortality compared to PCF, but treatment adherence is similar between the two groups, emphasizing the need to improve the linkage between screening, diagnosis, and treatment for the screened population.

Background: The increasing rate of excess body weight (EBW) in the global population has led to growing health concerns, including cancer-related EBW. We aimed to estimate the population attributable fraction (PAF) of cancer incidence and deaths linked to EBW in Korean individuals from 2015 to 2030 and to compare its value with various body mass index cutoffs. Methods: Levin’s formula was used to calculate the PAF; the prevalence rates were computed using the Korean National Health and Nutrition Examination Survey data, while the relative risks of specific cancers related to EBW were estimated based on the results of Korean cohort studies. To account for the 15-year latency period when estimating the PAF in 2020, the prevalence rates from 2015 and attributable cases or deaths from 2020 were used. Results: The PAF attributed to EBW was similar for both cancer incidence and deaths using either the World Health Organization (WHO) Asian-Pacific region standard or a modified Asian standard, with the WHO standard yielding the lowest values. In the Korean population, the PAFs of EBW for cancer incidence were 2.96% in men and 3.61% in women, while those for cancer deaths were 0.67% in men and 3.06% in women in 2020. Additionally, PAFs showed a gradual increase in both sexes until 2030. Conclusion The EBW continues to have a significant impact on cancer incidence and deaths in Korea. Effective prevention strategies targeting the reduction of this modifiable risk factor can substantially decrease the cancer burden.

OBJECTIVES: We aimed to assess the impact of obesity on mortality in middle-aged Koreans using data from a Health Examinees study. METHODS: We used data from the participants who had complete information on body size and gave informed consent for the linkage of their data with the national death certificate data. Cox proportional hazard model was used to estimate the hazard ratios and 95% confidence intervals (CIs) of body mass index (BMI) and waist-to-hip ratio (WHR) for all-cause, cardiovascular, and cancer mortality. RESULTS: A total of 115,961 participants were included in the study. The results showed a U-shaped association between BMI and mortality, indicating that both males and females with BMIs of less than 21.0 kg/m2 and greater than or equal to 30.0 kg/m2 are at increased risk. The results showed that males with a BMI of less than 18.5 kg/m² had a significantly higher risk of all-cause mortality (adjusted hazard ratio [aHR], 2.24; 95% CI, 1.73 to 2.91) and cardiovascular mortality (aHR, 2.27; 95% CI, 1.23 to 4.20). Similarly, males with a WHR of less than 0.80 (aHR, 1.38; 95% CI, 1.08 to 1.77), 0.90 to less than 0.95 (aHR, 1.15; 95% CI, 1.02 to 1.29), and greater than or equal to 0.95 (aHR, 1.28; 95% CI, 1.11 to 1.47) showed an increased risk of all-cause mortality. In females, a BMI of less than 18.0 kg/m2 was linked to a higher risk of cardiovascular mortality (aHR, 2.67; 95% CI, 1.13 to 6.33). CONCLUSIONS Being underweight was associated with an increased risk of mortality in both sexes, and the lowest risk of death was found in males who were slightly overweight with a BMI of 23.0-25.0 kg/m2.

OBJECTIVES: We aimed to assess the impact of obesity on mortality in middle-aged Koreans using data from a Health Examinees study. METHODS: We used data from the participants who had complete information on body size and gave informed consent for the linkage of their data with the national death certificate data. Cox proportional hazard model was used to estimate the hazard ratios and 95% confidence intervals (CIs) of body mass index (BMI) and waist-to-hip ratio (WHR) for all-cause, cardiovascular, and cancer mortality. RESULTS: A total of 115,961 participants were included in the study. The results showed a U-shaped association between BMI and mortality, indicating that both males and females with BMIs of less than 21.0 kg/m2 and greater than or equal to 30.0 kg/m2 are at increased risk. The results showed that males with a BMI of less than 18.5 kg/m² had a significantly higher risk of all-cause mortality (adjusted hazard ratio [aHR], 2.24; 95% CI, 1.73 to 2.91) and cardiovascular mortality (aHR, 2.27; 95% CI, 1.23 to 4.20). Similarly, males with a WHR of less than 0.80 (aHR, 1.38; 95% CI, 1.08 to 1.77), 0.90 to less than 0.95 (aHR, 1.15; 95% CI, 1.02 to 1.29), and greater than or equal to 0.95 (aHR, 1.28; 95% CI, 1.11 to 1.47) showed an increased risk of all-cause mortality. In females, a BMI of less than 18.0 kg/m2 was linked to a higher risk of cardiovascular mortality (aHR, 2.67; 95% CI, 1.13 to 6.33). CONCLUSIONS Being underweight was associated with an increased risk of mortality in both sexes, and the lowest risk of death was found in males who were slightly overweight with a BMI of 23.0-25.0 kg/m2.

Background: The increasing rate of excess body weight (EBW) in the global population has led to growing health concerns, including cancer-related EBW. We aimed to estimate the population attributable fraction (PAF) of cancer incidence and deaths linked to EBW in Korean individuals from 2015 to 2030 and to compare its value with various body mass index cutoffs. Methods: Levin’s formula was used to calculate the PAF; the prevalence rates were computed using the Korean National Health and Nutrition Examination Survey data, while the relative risks of specific cancers related to EBW were estimated based on the results of Korean cohort studies. To account for the 15-year latency period when estimating the PAF in 2020, the prevalence rates from 2015 and attributable cases or deaths from 2020 were used. Results: The PAF attributed to EBW was similar for both cancer incidence and deaths using either the World Health Organization (WHO) Asian-Pacific region standard or a modified Asian standard, with the WHO standard yielding the lowest values. In the Korean population, the PAFs of EBW for cancer incidence were 2.96% in men and 3.61% in women, while those for cancer deaths were 0.67% in men and 3.06% in women in 2020. Additionally, PAFs showed a gradual increase in both sexes until 2030. Conclusion The EBW continues to have a significant impact on cancer incidence and deaths in Korea. Effective prevention strategies targeting the reduction of this modifiable risk factor can substantially decrease the cancer burden.