1.National Trends in Influenza Vaccination Rates in South Korea Before and During the COVID-19 Pandemic, 2011-2022.
Kyeongeun KIM ; Kyeongmin LEE ; Yejun SON ; Seoyoung PARK ; Raphael UDEH ; Jiseung KANG ; Hayeon LEE ; Soeun KIM ; Jaeyu PARK ; Hyeon Jin KIM ; Damiano PIZZOL ; Lee SMITH ; Jiyoung HWANG ; Dong Keon YON
Biomedical and Environmental Sciences 2025;38(9):1044-1057
OBJECTIVE:
Despite the global decrease in influenza infections during the coronavirus disease 2019 (COVID-19) pandemic, seasonal influenza remains a significant health issue. South Korea, known for its robust pandemic response and high influenza vaccination rates, offers a unique context for examining changes in vaccination trends during the pandemic. Using nationally representative data, we aimed to understand the impact of the pandemic on influenza vaccination behavior over a 12-year period and to identify vulnerable groups.
METHODS:
We analyzed influenza vaccination rates in South Korea between 2011-2022, focusing on pandemic-related impacts. The data of 2,426,139 adults (≥ 19 years) from the Korea Community Health Survey were used to assess demographic and sociological factors influencing vaccination behaviors.
RESULTS:
We observed an increase in influenza vaccination rates during the pre-COVID-19 period from 2011-2013 (weighted prevalence: 46.68% [95% confidence interval ( CI): 46.55-46.82]) to 2017-2019 (weighted prevalence: 52.50% [95% CI: 52.38-52.63]). However, a significant decline was observed in 2022, the late-COVID-19 pandemic period (weighted prevalence: 55.78% [95% CI: 55.56-56.01]), compared with the mid-pandemic period in 2021 (weighted prevalence: 59.12% [95% CI: 58.91-59.32]), particularly among populations traditionally prioritized for influenza vaccination, including older adults (≥ 65 years) and patients with chronic diseases and low educational and income levels.
CONCLUSION
The influenza vaccination rate in South Korea was significantly affected by the COVID-19 pandemic, showing a notable decrease among vulnerable demographic groups. This suggests the need for targeted public health strategies to address vaccine hesitancy and improve vaccination rates, particularly among high-risk populations.
Humans
;
Republic of Korea/epidemiology*
;
COVID-19/epidemiology*
;
Adult
;
Middle Aged
;
Influenza Vaccines/administration & dosage*
;
Male
;
Female
;
Influenza, Human/epidemiology*
;
Aged
;
Vaccination/statistics & numerical data*
;
Young Adult
;
Pandemics
;
SARS-CoV-2
2.Determinants of Prostate Cancer Screening in Korean Men: A Nationwide Study Using the Korean National Cancer Screening Survey 2023
Giap Viet NGUYEN ; Kyeongmin LEE ; Hyeon Ji LEE ; EunKyo KANG ; Mina SUH ; Jae Kwan JUN ; Kui Son CHOI
Cancer Research and Treatment 2025;57(2):539-546
Purpose:
Research on the prevalence of prostate cancer (PCa) screening and reasons for undergoing screening is limited. We aimed to identify the factors influencing PCa screening behavior and explore the underlying motivations among Korean men.
Materials and Methods:
This cross-sectional study used data from the 2023 Korean National Cancer Screening Survey, which employs a nationally representative random sampling method. This study included 1,784 men aged 40-74 years. The respondents reported their experiences with PCa screening. Multivariable logistic regression analysis was conducted to identify the factors associated with participation in PCa screening.
Results:
The lifetime PCa screening rate was 18.6%. Among screening modalities, transrectal ultrasonography was the most frequently used (31.9%), followed by prostate-specific antigen tests (25.6%) and digital rectal examinations (21.5%). The multivariable analysis identified several factors that significantly increased the likelihood of screening participation, including older age, living with a spouse, poor self-reported health, and abstinence from alcohol consumption in the previous 12 months. Men who had undergone colorectal cancer screening were more likely to participate in PCa screening (adjusted odds ratio, 4.01; 95% confidence interval, 2.03 to 7.93) than those who had not. The primary motivations for screening were recommendations from family or social networks (31.9%) and inclusion in health examination packages (24.3%), whereas healthcare provider recommendations (18%) and symptomatic concerns (5.7%) were the least influential.
Conclusion
Our findings highlight the importance of providing evidence-based information for PCa screening recommendations and the need for improved communication and implementation of a shared decision-making approach for PCa screening in Korea.
3.Cost Utility Analysis of National Cancer Screening Program for Gastric Cancer in Korea: A Markov Model Analysis
Seowoo BAE ; Hyewon LEE ; Eun Young HER ; Kyeongmin LEE ; Joon Sung KIM ; Jeonghoon AHN ; Il Ju CHOI ; Jae Kwan JUN ; Kui Son CHOI ; Mina SUH
Journal of Korean Medical Science 2025;40(6):e43-
Background:
The Korean National Cancer Screening Program (NCSP) for gastric cancer requires economic evaluation due to the low sensitivity of upper gastrointestinal series (UGIs) and the associated low cancer survival rate. This study aimed to ascertain the most cost-effective strategy for the NCSP.
Methods:
The hypothetical target population of this study was aged 40 years or older, and no actual participants were involved. Markov simulation models were constructed for 25 strategies, combinations of 1) screening methods (UGIs or endoscopy vs. endoscopy-only), 2) screening intervals (one, two, or three-year), and 3) upper age limit of screening (69, 74, 79 years old, or “no limit”). Costs, utility, and other input parameters were extracted from various databases and previous studies. Cost-utility, sensitivity, and scenario analyses were conducted.
Results:
The endoscopy-only strategy with a three-year interval with an upper age limit of 69 was the most cost-effective strategy with an incremental cost-utility ratio of KRW 13,354,106 per quality-adjusted life years. According to the probabilistic sensitivity analysis, the uncertainty of the result was significantly small. Scenario analysis is showed that as the screening rate increased, the endoscopy-only strategy saved more costs compared to the current NCSP. Therefore, it is important to maintain a high screening rate when altering the NCSP strategy.
Conclusion
Endoscopy-only screening was more cost-effective method than UGIs for the NCSP. Furthermore, a three-year interval with an upper-age limit of 69 years was the most cost-effective strategy. Efforts to improve cost-effective screening guidelines will support the efficient use of medical resources. Additionally, maintaining a higher screening rate may maximize the impact of the modification in strategy on cost-effectiveness.
4.Non-Linear Association Between Physical Activities and Type 2Diabetes in 2.4 Million Korean Population, 2009–2022: A Nationwide Representative Study
Wonwoo JANG ; Seokjun KIM ; Yejun SON ; Soeun KIM ; Hayeon LEE ; Jaeyu PARK ; Kyeongmin LEE ; Jiseung KANG ; Damiano PIZZOL ; Jiyoung HWANG ; Sang Youl RHEE ; Dong Keon YON
Journal of Korean Medical Science 2025;40(12):e42-
Background:
Although excessive physical activity (PA) does not always confer additional health benefits, there is a paucity of studies that have quantitatively examined the doseresponse relationship between PA and type 2 diabetes. Therefore, this study investigated the relationship between the type 2 diabetes prevalence and intensity, frequency, and metabolic equivalent of task (MET) score of PA in a large population sample.
Methods:
We conducted a nationwide cross-sectional analysis examining sociodemographic variables, PA habits, and type 2 diabetes prevalence in 2,428,448 participants included in the Korea Community Health Survey. The non-linear association between MET score and odds ratios (ORs) for type 2 diabetes prevalence was plotted using a weighted generalized additive model. Categorical analysis was used to examine the joint association of moderate-intensity PA (MPA) and vigorous-intensity PA (VPA), and the influence of PA frequency.
Results:
MET score and diabetes prevalence revealed a non-linear association with the nadir at 1,028 MET-min/week, beyond which ORs increased with additional PA. Joint analysis of MPA and VPA showed the lowest OR of 0.79 (95% confidence interval, 0.75–0.84) for those engaging in 300–600 MET-min/week of MPA and > 600 MET-min/week of VPA concurrently, corresponding with World Health Organization recommendations. Additionally, both “weekend warriors” and “regularly active” individuals showed lower ORs compared to the inactive, although no significant difference was noted between the active groups.
Conclusion
In a large South Korean sample, higher PA is not always associated with a lower prevalence of type 2 diabetes, as the association follows a non-linear pattern; differences existed across sociodemographic variables. Considering the joint association, an adequate combination of MPA and VPA is recommended. The frequency of PA does not significantly influence the type 2 diabetes prevalence.
5.Cost Utility Analysis of National Cancer Screening Program for Gastric Cancer in Korea: A Markov Model Analysis
Seowoo BAE ; Hyewon LEE ; Eun Young HER ; Kyeongmin LEE ; Joon Sung KIM ; Jeonghoon AHN ; Il Ju CHOI ; Jae Kwan JUN ; Kui Son CHOI ; Mina SUH
Journal of Korean Medical Science 2025;40(6):e43-
Background:
The Korean National Cancer Screening Program (NCSP) for gastric cancer requires economic evaluation due to the low sensitivity of upper gastrointestinal series (UGIs) and the associated low cancer survival rate. This study aimed to ascertain the most cost-effective strategy for the NCSP.
Methods:
The hypothetical target population of this study was aged 40 years or older, and no actual participants were involved. Markov simulation models were constructed for 25 strategies, combinations of 1) screening methods (UGIs or endoscopy vs. endoscopy-only), 2) screening intervals (one, two, or three-year), and 3) upper age limit of screening (69, 74, 79 years old, or “no limit”). Costs, utility, and other input parameters were extracted from various databases and previous studies. Cost-utility, sensitivity, and scenario analyses were conducted.
Results:
The endoscopy-only strategy with a three-year interval with an upper age limit of 69 was the most cost-effective strategy with an incremental cost-utility ratio of KRW 13,354,106 per quality-adjusted life years. According to the probabilistic sensitivity analysis, the uncertainty of the result was significantly small. Scenario analysis is showed that as the screening rate increased, the endoscopy-only strategy saved more costs compared to the current NCSP. Therefore, it is important to maintain a high screening rate when altering the NCSP strategy.
Conclusion
Endoscopy-only screening was more cost-effective method than UGIs for the NCSP. Furthermore, a three-year interval with an upper-age limit of 69 years was the most cost-effective strategy. Efforts to improve cost-effective screening guidelines will support the efficient use of medical resources. Additionally, maintaining a higher screening rate may maximize the impact of the modification in strategy on cost-effectiveness.
6.Non-Linear Association Between Physical Activities and Type 2Diabetes in 2.4 Million Korean Population, 2009–2022: A Nationwide Representative Study
Wonwoo JANG ; Seokjun KIM ; Yejun SON ; Soeun KIM ; Hayeon LEE ; Jaeyu PARK ; Kyeongmin LEE ; Jiseung KANG ; Damiano PIZZOL ; Jiyoung HWANG ; Sang Youl RHEE ; Dong Keon YON
Journal of Korean Medical Science 2025;40(12):e42-
Background:
Although excessive physical activity (PA) does not always confer additional health benefits, there is a paucity of studies that have quantitatively examined the doseresponse relationship between PA and type 2 diabetes. Therefore, this study investigated the relationship between the type 2 diabetes prevalence and intensity, frequency, and metabolic equivalent of task (MET) score of PA in a large population sample.
Methods:
We conducted a nationwide cross-sectional analysis examining sociodemographic variables, PA habits, and type 2 diabetes prevalence in 2,428,448 participants included in the Korea Community Health Survey. The non-linear association between MET score and odds ratios (ORs) for type 2 diabetes prevalence was plotted using a weighted generalized additive model. Categorical analysis was used to examine the joint association of moderate-intensity PA (MPA) and vigorous-intensity PA (VPA), and the influence of PA frequency.
Results:
MET score and diabetes prevalence revealed a non-linear association with the nadir at 1,028 MET-min/week, beyond which ORs increased with additional PA. Joint analysis of MPA and VPA showed the lowest OR of 0.79 (95% confidence interval, 0.75–0.84) for those engaging in 300–600 MET-min/week of MPA and > 600 MET-min/week of VPA concurrently, corresponding with World Health Organization recommendations. Additionally, both “weekend warriors” and “regularly active” individuals showed lower ORs compared to the inactive, although no significant difference was noted between the active groups.
Conclusion
In a large South Korean sample, higher PA is not always associated with a lower prevalence of type 2 diabetes, as the association follows a non-linear pattern; differences existed across sociodemographic variables. Considering the joint association, an adequate combination of MPA and VPA is recommended. The frequency of PA does not significantly influence the type 2 diabetes prevalence.
7.Determinants of Prostate Cancer Screening in Korean Men: A Nationwide Study Using the Korean National Cancer Screening Survey 2023
Giap Viet NGUYEN ; Kyeongmin LEE ; Hyeon Ji LEE ; EunKyo KANG ; Mina SUH ; Jae Kwan JUN ; Kui Son CHOI
Cancer Research and Treatment 2025;57(2):539-546
Purpose:
Research on the prevalence of prostate cancer (PCa) screening and reasons for undergoing screening is limited. We aimed to identify the factors influencing PCa screening behavior and explore the underlying motivations among Korean men.
Materials and Methods:
This cross-sectional study used data from the 2023 Korean National Cancer Screening Survey, which employs a nationally representative random sampling method. This study included 1,784 men aged 40-74 years. The respondents reported their experiences with PCa screening. Multivariable logistic regression analysis was conducted to identify the factors associated with participation in PCa screening.
Results:
The lifetime PCa screening rate was 18.6%. Among screening modalities, transrectal ultrasonography was the most frequently used (31.9%), followed by prostate-specific antigen tests (25.6%) and digital rectal examinations (21.5%). The multivariable analysis identified several factors that significantly increased the likelihood of screening participation, including older age, living with a spouse, poor self-reported health, and abstinence from alcohol consumption in the previous 12 months. Men who had undergone colorectal cancer screening were more likely to participate in PCa screening (adjusted odds ratio, 4.01; 95% confidence interval, 2.03 to 7.93) than those who had not. The primary motivations for screening were recommendations from family or social networks (31.9%) and inclusion in health examination packages (24.3%), whereas healthcare provider recommendations (18%) and symptomatic concerns (5.7%) were the least influential.
Conclusion
Our findings highlight the importance of providing evidence-based information for PCa screening recommendations and the need for improved communication and implementation of a shared decision-making approach for PCa screening in Korea.
8.Cost Utility Analysis of National Cancer Screening Program for Gastric Cancer in Korea: A Markov Model Analysis
Seowoo BAE ; Hyewon LEE ; Eun Young HER ; Kyeongmin LEE ; Joon Sung KIM ; Jeonghoon AHN ; Il Ju CHOI ; Jae Kwan JUN ; Kui Son CHOI ; Mina SUH
Journal of Korean Medical Science 2025;40(6):e43-
Background:
The Korean National Cancer Screening Program (NCSP) for gastric cancer requires economic evaluation due to the low sensitivity of upper gastrointestinal series (UGIs) and the associated low cancer survival rate. This study aimed to ascertain the most cost-effective strategy for the NCSP.
Methods:
The hypothetical target population of this study was aged 40 years or older, and no actual participants were involved. Markov simulation models were constructed for 25 strategies, combinations of 1) screening methods (UGIs or endoscopy vs. endoscopy-only), 2) screening intervals (one, two, or three-year), and 3) upper age limit of screening (69, 74, 79 years old, or “no limit”). Costs, utility, and other input parameters were extracted from various databases and previous studies. Cost-utility, sensitivity, and scenario analyses were conducted.
Results:
The endoscopy-only strategy with a three-year interval with an upper age limit of 69 was the most cost-effective strategy with an incremental cost-utility ratio of KRW 13,354,106 per quality-adjusted life years. According to the probabilistic sensitivity analysis, the uncertainty of the result was significantly small. Scenario analysis is showed that as the screening rate increased, the endoscopy-only strategy saved more costs compared to the current NCSP. Therefore, it is important to maintain a high screening rate when altering the NCSP strategy.
Conclusion
Endoscopy-only screening was more cost-effective method than UGIs for the NCSP. Furthermore, a three-year interval with an upper-age limit of 69 years was the most cost-effective strategy. Efforts to improve cost-effective screening guidelines will support the efficient use of medical resources. Additionally, maintaining a higher screening rate may maximize the impact of the modification in strategy on cost-effectiveness.
9.Non-Linear Association Between Physical Activities and Type 2Diabetes in 2.4 Million Korean Population, 2009–2022: A Nationwide Representative Study
Wonwoo JANG ; Seokjun KIM ; Yejun SON ; Soeun KIM ; Hayeon LEE ; Jaeyu PARK ; Kyeongmin LEE ; Jiseung KANG ; Damiano PIZZOL ; Jiyoung HWANG ; Sang Youl RHEE ; Dong Keon YON
Journal of Korean Medical Science 2025;40(12):e42-
Background:
Although excessive physical activity (PA) does not always confer additional health benefits, there is a paucity of studies that have quantitatively examined the doseresponse relationship between PA and type 2 diabetes. Therefore, this study investigated the relationship between the type 2 diabetes prevalence and intensity, frequency, and metabolic equivalent of task (MET) score of PA in a large population sample.
Methods:
We conducted a nationwide cross-sectional analysis examining sociodemographic variables, PA habits, and type 2 diabetes prevalence in 2,428,448 participants included in the Korea Community Health Survey. The non-linear association between MET score and odds ratios (ORs) for type 2 diabetes prevalence was plotted using a weighted generalized additive model. Categorical analysis was used to examine the joint association of moderate-intensity PA (MPA) and vigorous-intensity PA (VPA), and the influence of PA frequency.
Results:
MET score and diabetes prevalence revealed a non-linear association with the nadir at 1,028 MET-min/week, beyond which ORs increased with additional PA. Joint analysis of MPA and VPA showed the lowest OR of 0.79 (95% confidence interval, 0.75–0.84) for those engaging in 300–600 MET-min/week of MPA and > 600 MET-min/week of VPA concurrently, corresponding with World Health Organization recommendations. Additionally, both “weekend warriors” and “regularly active” individuals showed lower ORs compared to the inactive, although no significant difference was noted between the active groups.
Conclusion
In a large South Korean sample, higher PA is not always associated with a lower prevalence of type 2 diabetes, as the association follows a non-linear pattern; differences existed across sociodemographic variables. Considering the joint association, an adequate combination of MPA and VPA is recommended. The frequency of PA does not significantly influence the type 2 diabetes prevalence.
10.Determinants of Prostate Cancer Screening in Korean Men: A Nationwide Study Using the Korean National Cancer Screening Survey 2023
Giap Viet NGUYEN ; Kyeongmin LEE ; Hyeon Ji LEE ; EunKyo KANG ; Mina SUH ; Jae Kwan JUN ; Kui Son CHOI
Cancer Research and Treatment 2025;57(2):539-546
Purpose:
Research on the prevalence of prostate cancer (PCa) screening and reasons for undergoing screening is limited. We aimed to identify the factors influencing PCa screening behavior and explore the underlying motivations among Korean men.
Materials and Methods:
This cross-sectional study used data from the 2023 Korean National Cancer Screening Survey, which employs a nationally representative random sampling method. This study included 1,784 men aged 40-74 years. The respondents reported their experiences with PCa screening. Multivariable logistic regression analysis was conducted to identify the factors associated with participation in PCa screening.
Results:
The lifetime PCa screening rate was 18.6%. Among screening modalities, transrectal ultrasonography was the most frequently used (31.9%), followed by prostate-specific antigen tests (25.6%) and digital rectal examinations (21.5%). The multivariable analysis identified several factors that significantly increased the likelihood of screening participation, including older age, living with a spouse, poor self-reported health, and abstinence from alcohol consumption in the previous 12 months. Men who had undergone colorectal cancer screening were more likely to participate in PCa screening (adjusted odds ratio, 4.01; 95% confidence interval, 2.03 to 7.93) than those who had not. The primary motivations for screening were recommendations from family or social networks (31.9%) and inclusion in health examination packages (24.3%), whereas healthcare provider recommendations (18%) and symptomatic concerns (5.7%) were the least influential.
Conclusion
Our findings highlight the importance of providing evidence-based information for PCa screening recommendations and the need for improved communication and implementation of a shared decision-making approach for PCa screening in Korea.

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