1.Effects of student human rights ordinances on mental health among middle and high school students in South Korea: a difference-in-differences analysis
Epidemiology and Health 2025;47(1):e2025011-
OBJECTIVES:
To actively protect and enhance students’ human rights, student human rights ordinances (SHROs) have been enforced in seven provinces in South Korea at different times since 2010. Although human rights are closely linked to mental health, there has been no research on the effectiveness of human rights legislation on adolescent mental health. This study evaluated the effects of SHROs on the mental health of middle and high school students.
METHODS:
Repeated cross-sectional data were used, including 1,148,257 respondents from the Korea Youth Risk Behavior Web-based Survey between 2006 and 2023. Probabilities of perceived stress, sleep insufficiency, depressive mood, suicide ideation, and suicide attempt in treated provinces were estimated through a difference-in-differences approach that accounts for treatment effect heterogeneity across groups over time.
RESULTS:
SHROs had no consistently significant effects on any mental health outcomes, except for slightly increased suicide ideation in total students (0.7%, 95% confidence interval 0.3% to 1.1%). Suicide attempts in total and male students and perceived stress and sleep insufficiency in female students tended to decrease, while other mental health outcomes tended to increase. Uncertainty in the effect estimates of SHROs increased for all mental health outcomes with possible violations of parallel trends, rendering originally significant effects insignificant.
CONCLUSIONS
SHROs failed to improve mental health of middle and high school students in treated provinces, possibly due to the absence of enforcement mechanisms. Further research is needed on the effectiveness of and effect mechanisms for legal measures to improve human rights on adolescent mental health.
2.Prevalence of cardiovascular-kidney-metabolic syndrome in Korea: Korea National Health and Nutrition Examination Survey 2011-2021
Sung-Bin HONG ; Ji-Eun KIM ; Seung Seok HAN ; Joseph J. SHEARER ; Jungnam JOO ; Ji-Yeob CHOI ; Véronique L. ROGER
Epidemiology and Health 2025;47(1):e2025005-
OBJECTIVES:
The American Heart Association (AHA) recently defined cardiovascular-kidney-metabolic (CKM) syndrome to better characterize the associations among cardiovascular, kidney, and metabolic diseases. Although about 9 in 10 United States adults have at least 1 risk factor for CKM syndrome, its prevalence in other populations is less understood. To fill this gap, we examined the prevalence of CKM syndrome in Korea and its association with demographic and socioeconomic status (SES).
METHODS:
Using data from the Korean National Health and Nutrition Examination Survey between 2011 and 2021, we calculated the prevalence of CKM syndrome across the following stages: stage 0 (no risk factors), stage 1 (excess or dysfunctional adiposity), stage 2 (other metabolic risk factors or chronic kidney disease), and stages 3-4 (subclinical/clinical cardiovascular diseases) among adults aged ≥20 years. Weighted analyses were used to estimate prevalence and 95% confidence intervals (CIs) for each CKM syndrome stage, stratified by age, gender, and SES factors.
RESULTS:
Among 54,994 Korean adults, the prevalence of CKM syndrome was as follows: stage 0 (25.2%; 95% CI, 24.7 to 25.8), stage 1 (19.3%; 95% CI, 18.9 to 19.7), stage 2 (51.6%; 95% CI, 51.1 to 52.2), and stages 3-4 (3.9%; 95% CI, 3.7 to 4.0). The prevalence of stages 2 and 3-4 was higher in men than in women. In addition, stages 3-4 were more prevalent among rural residents and those with lower education or income.
CONCLUSIONS
About 3 out of 4 Koreans are at risk for CKM syndrome. These findings highlight that CKM syndrome is a global health problem and that interventions are urgently needed to prevent further progression.
3.Levels of exposure markers among residents in environmentally vulnerable areas in Korea, the general population in Korea, and Asians in the United States
Kyung-Hwa CHOI ; Dahee HAN ; Sang-Yong EOM ; Yong Min CHO ; Young-Seoub HONG ; Woo Jin KIM
Epidemiology and Health 2025;47(1):e2025007-
This study compares biomarker levels among environmentally vulnerable residents in Korea, the general Korean population, and Asians in the United States. We selected 953 exposed residents and 204 controls from the Forensic Research via Omics Markers in Environmental Health Vulnerable Areas (FROM) study (2021-2023), 4,239 participants from the fourth Korean National Environmental Health Survey (2018-2020), and 996 Asians from the U.S. National Health and Nutrition Examination Survey (2017-March 2020). The analyzed biomarkers included blood and urinary metals, urinary metabolites of polycyclic aromatic hydrocarbons, nicotine, volatile organic compounds, and serum perfluorocarbon metabolites. The highest median biomarker levels varied by pollution source among older adults. In refineries, blood lead and cadmium (Cd), as well as urinary Cd and 2-hydroxyfluorene, were highest. Abandoned metal mines exhibited the highest blood and urinary mercury, urinary Cd, total arsenic (As), 2-naphthol, and cotinine levels. Coal-fired power plants showed the highest urinary 1- hydroxyphenanthrene levels, while cement factories had the highest urinary As3+ levels. Sprawls demonstrated the highest urinary monomethylarsonic acid, 1-hydroxypyrene, and phenylglyoxylic acid levels, and industrial areas recorded the highest levels of trans, trans-muconic acid, benzylmercapturic acid, and 2-methylhippuric acid. In general, biomarker levels were higher among exposed residents in the FROM study than in the general population; however, urinary 2-hydroxyfluorene and As5+ levels did not differ significantly. Exposure to pollution sources in environmentally vulnerable areas may elevate biomarker levels in residents.
4.Cohort profile: a nationwide retrospective cohort of mortality in people living with HIV in Korea, 1985-2020
Taeyoung KIM ; Yoonhee JUNG ; Koun KIM ; Jung Wan PARK ; Jeonghee YU ; Sung-il CHO
Epidemiology and Health 2025;47(1):e2025002-
The increasing number of people living with human immunodeficiency virus (HIV) in Korea has prompted interest in using the national surveillance system as a database for studying their health. To investigate the relationships between socio-demographic and epidemiological characteristics and mortality rates, a nationwide retrospective cohort was formed by integrating surveillance data with the Cause of Death Statistics from Statistics Korea. This integration included incidence reports, epidemiological investigations, and death reports from the surveillance data, enriched with detailed mortality information from the Cause of Death data. The cohort comprised 17,199 adult Korean individuals diagnosed with HIV infection from 1985 to 2020. By the end of 2020, 2,721 of these individuals were confirmed deceased. The sex ratio of the study participants was 14.3:1.0 (male to female), with 78.2% being under 50 years old at the time of diagnosis. Sexual contact was identified as the primary transmission route, accounting for 75.7% of cases. HIV disease emerged as the predominant cause of death, representing two-thirds (1,817 of 2,721) of the fatalities, followed by injuries and trauma, malignancies, and cardiovascular diseases. Recommendations for further cohort studies may be submitted to the Korea Disease Control and Prevention Agency.
5.Gender differences in awareness and practices of cancer prevention recommendations in Korea:a cross-sectional survey
Yoonjoo CHOI ; Naeun KIM ; Jin-Kyoung OH ; Yoon-Jung CHOI ; Bohyun PARK ; Byungmi KIM
Epidemiology and Health 2025;47(1):e2025003-
OBJECTIVES:
Gender is a major determinant of health behaviors that influences cancer prevention awareness and practices. This study investigated the relationship of the awareness and practice rates of cancer prevention recommendations with gender and socioeconomic status.
METHODS:
We used data from the Korean National Cancer Prevention Awareness and Practice Survey (2023). The sample included 4,000 men and women aged 20-74 years. We conducted multiple logistic regression analyses to evaluate associations with the awareness and practices of cancer prevention, and a joinpoint regression analysis using age-standardized rates to analyze trends in awareness and practice rates from 2007 to 2023.
RESULTS:
The awareness rates were 79.4% and 81.2% for men and women, respectively. The overall practice rates were substantially lower (43.1% for men and 48.9% for women). For men, awareness rates did not differ significantly by socio-demographic characteristics, but practice rates increased with age (20-29: 15.9%; 60-74: 53.8%). For women, both awareness (20-29: 73.0%; 60-74: 85.7%) and practice (20-29: 16.8%; 60-74: 67.5%) rates increased with age. The easiest recommendations to follow were “reducing salt intake and avoiding burnt or charred foods” (men: 29.9%; women: 28.4%), whereas the most difficult recommendation was “engaging in regular physical activity” (men: 32.5%; women: 34.4%).
CONCLUSIONS
While awareness of cancer prevention recommendations was high, the practice of these recommendations was low. Gender influenced changes in awareness and practice rates over time, reflecting a large gap in practice. Future research should explore appropriate intervention points for cancer prevention practices and the development of more effective cancer prevention policies.
6.Risk of non-cancer respiratory diseases attributed to humidifier disinfectant exposure in Koreans: age-period-cohort and differences-in-difference analyses
Jaiyong KIM ; Kyoung Sook JEONG ; Seungyeon HEO ; Younghee KIM ; Jungyun LIM ; Sol YU ; Suejin KIM ; Sun-Kyoung SHIN ; Hae-Kwan CHEONG ; Mina HA ;
Epidemiology and Health 2025;47(1):e2025006-
OBJECTIVES:
Humidifier disinfectants (HDs) were sold in Korea from 1994 until their recall in 2011. We examined the incidence patterns of 8 respiratory diseases before and after the HD recall and estimated the attributable risk in the Korean population.
METHODS:
Using National Health Insurance data from 2002 to 2019, we performed age–cohort–period and differences-in-diffference analyses (comparing periods before vs. after the recall) to estimate the population-attributable fraction and the excess number of episodes. The database comprised 51 million individuals (99% of the Korean population). The incidence of 8 diseases—acute upper respiratory infection (AURI), acute lower respiratory infection (ALRI), asthma, pneumonia, chronic sinusitis (CS), interstitial lung disease (ILD), bronchiectasis, and chronic obstructive pulmonary disease (COPD)—was defined by constructing episodes of care based on patterns of medical care and the clinical characteristics of each disease.
RESULTS:
The relative risks (RRs) for AURI, ALRI, asthma, pneumonia, CS, and ILD were elevated among younger individuals (with an RR as high as 82.18 for AURI in males), whereas chronic conditions such as bronchiectasis, COPD, and ILD showed higher RRs in older individuals. During the HD exposure period, the population-attributable risk percentage ranged from 4.6% for bronchiectasis to 25.1% for pneumonia, with the excess number of episodes ranging from 6,218 for ILD to 3,058,861 for CS. Notably, females of reproductive age (19-44 years) experienced 1.1-9.2 times more excess episodes than males.
CONCLUSIONS
This study provides epidemiological evidence that inhalation exposure to HDs affects the entire respiratory tract and identifies vulnerable groups.
8.A comparison of the outcomes of families with children aged less than 2 who received universal versus sustained nurse home visiting services in Korea: a cross-sectional study
Yu-Mi KIM ; Sun Hwa PARK ; Kyung Ja JUNE ; Sung-Hyun CHO ; Ji Yun LEE ; Hong-Jun CHO ; Young-Ho KHANG
Epidemiology and Health 2025;47(1):e2025004-
OBJECTIVES:
This study aimed to compare maternal outcomes and the home environment between non‑vulnerable families with children under 2 receiving universal home visiting services and vulnerable families receiving sustained home visiting services.
METHODS:
This study was conducted in Seoul, Korea, where the country’s first nurse‑led early childhood home visiting program was introduced. A total of 551 mother‑child dyads participated in cross‑sectional surveys conducted at various child ages (6±2 weeks, 6±1 months, 12±1 months, and 24±1 months). Universal home visiting services were provided within six weeks postpartum to non‑vulnerable families, while vulnerable families received sustained services consisting of 25 visits over 24 months. Maternal knowledge of sudden infant death syndrome (SIDS) and childcare, maternal distress, and the Korean Infant‑Toddler Home Observation for Measurement of Environment (K‑IT‑HOME) were assessed.
RESULTS:
Overall, the universal home visitation group demonstrated higher levels of maternal knowledge regarding SIDS and childcare compared to the sustained home visitation group (all p-values <0.05), while the sustained home visitation group reported higher levels of maternal distress (p<0.001). The total K‑IT‑HOME score was 1.47 points higher in the universal home visitation group than in the sustained home visitation group (p<0.001). No significant differences were observed in the acceptance, organization, or involvement subscales of the K‑IT‑HOME (all p-values >0.05).
CONCLUSIONS
This study demonstrated that disparities in maternal outcomes and home environments persisted in early childhood between the sustained and universal home visitation groups.
9.Prospective association between handgrip strength in childhood and the metabolic syndrome score and insulin resistance indices in adolescence: an analysis based on the Ewha Birth and Growth Study
Seunghee JUN ; Hyunjin PARK ; Hyelim LEE ; Hye Ah LEE ; Young Sun HONG ; Hyesook PARK
Epidemiology and Health 2025;47(1):e2025001-
OBJECTIVES:
Low handgrip strength (HGS) in children and adolescents might be associated with the risk of metabolic syndrome (MetS) and insulin resistance. This study prospectively evaluated the association between HGS in childhood and MetS in adolescence.
METHODS:
Based on data from the Ewha Birth and Growth Study, this study analyzed HGS at ages 7 to 9 and metabolic indices at ages 13 to 15. In total, 219 participants were analyzed. The risk of MetS was evaluated using the continuous metabolic syndrome score (cMetS), and insulin resistance was assessed using fasting blood insulin and homeostasis model assessment of insulin resistance (HOMA-IR). Relative HGS in childhood was determined by dividing HGS by body weight and categorized as sex-specific quartiles.
RESULTS:
This study found an inverse association between relative HGS levels in childhood and MetS and insulin resistance in adolescence. For each 1-group increase in relative HGS quartiles, cMetS (standarard [Std] β=-0.64, p<0.01), HOMA-IR (Std β=-0.21, p<0.01), and fasting blood insulin (Std β=-0.21, p<0.01) all decreased on average. These associations remained significant even after adjusting for confounding factors.
CONCLUSIONS
Our study showed a prospective association between HGS in childhood and the risk of MetS and insulin resistance in adolescence. It provides significant epidemiological evidence, emphasizing the importance of efforts to increase muscle strength from a young age to mitigate the risk of MetS and insulin resistance in adolescence.
10.Effects of student human rights ordinances on mental health among middle and high school students in South Korea: a difference-in-differences analysis
Epidemiology and Health 2025;47(1):e2025011-
OBJECTIVES:
To actively protect and enhance students’ human rights, student human rights ordinances (SHROs) have been enforced in seven provinces in South Korea at different times since 2010. Although human rights are closely linked to mental health, there has been no research on the effectiveness of human rights legislation on adolescent mental health. This study evaluated the effects of SHROs on the mental health of middle and high school students.
METHODS:
Repeated cross-sectional data were used, including 1,148,257 respondents from the Korea Youth Risk Behavior Web-based Survey between 2006 and 2023. Probabilities of perceived stress, sleep insufficiency, depressive mood, suicide ideation, and suicide attempt in treated provinces were estimated through a difference-in-differences approach that accounts for treatment effect heterogeneity across groups over time.
RESULTS:
SHROs had no consistently significant effects on any mental health outcomes, except for slightly increased suicide ideation in total students (0.7%, 95% confidence interval 0.3% to 1.1%). Suicide attempts in total and male students and perceived stress and sleep insufficiency in female students tended to decrease, while other mental health outcomes tended to increase. Uncertainty in the effect estimates of SHROs increased for all mental health outcomes with possible violations of parallel trends, rendering originally significant effects insignificant.
CONCLUSIONS
SHROs failed to improve mental health of middle and high school students in treated provinces, possibly due to the absence of enforcement mechanisms. Further research is needed on the effectiveness of and effect mechanisms for legal measures to improve human rights on adolescent mental health.

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