Data Resource Profile: The Korea Youth Risk Behavior Web-based Survey (KYRBS)

Adolescents smartphone screen time and its association with caries symptoms experience from the Korea youth risk behavior web-based survey 2020-2021

Adolescence is a time when important changes occur in behavioral development, and previous studies have confirmed the relationship between excessive Internet use and decreased oral health behavior. Our purpose is to identify the indirect effects and behavioral factors of smartphone screen time on the caries symptom experience of adolescents. Using data from the 16-17th Korea youth risk behavior web based survey (2020-2021), we investigated the smartphone screen time of 109,796 students in middle school 1st to high school 3rd. Adolescents who used smartphones more than 6 h per week were 28% more likely to experience caries symptoms than those who used smartphones less than 2 h (odds ratio = 1.28; 95% confidence interval, 1.22-1.35). Those who consumed cariogenic drinks more than once a day were 25% more likely to experience caries symptoms, and those who brushed their teeth less than once a day were 26% more likely to experience caries symptoms (odds ratio = 1.25, 1.26; 95% confidence interval, 1.07-1.46, 1.06-1.51). Excessive smartphone screen time is associated with addictive eating habits and reduced physical activity that increase cariogenic dietary behaviors, and decrease oral health behaviors. It suggests that excessive smartphone use indirectly related to the experience of caries symptoms.

National trends in adolescents' mental health by income level in South Korea, pre- and post-COVID-19, 2006-2022

Despite the significant impact of the COVID-19 pandemic on various factors related to adolescent mental health problems such as stress, sadness, suicidal ideation, and suicide attempts, research on this topic has been insufficient to date. This study is based on the Korean Youth Risk Behavior Web-based Survey from 2006 to 2022. We analyzed the mental health problems of adolescents based on questionnaires with medical interviews, within five income groups and compared them with several risk factors. A total of 1,138,804 participants were included in this study, with a mean age (SD) of 15.01 (0.75) years. Of these, 587,256 were male (51.57%). In 2022, the recent period from the study, the weighted prevalence of stress in highest income group was 40.07% (95% CI, 38.67-41.48), sadness was 28.15% (26.82-29.48), suicidal ideation was 13.92% (12.87-14.97), and suicide attempts was 3.42% (2.90-3.93) while the weighted prevalence of stress in lowest income group was 62.77% (59.42-66.13), sadness was 46.83% (43.32-50.34), suicidal ideation was 31.70% (28.44-34.96), and suicide attempts was 10.45% (8.46-12.45). Lower income groups showed a higher proportion with several risk factors. Overall proportion had decreased until the onset of the pandemic. However, a significant increase has been found during the COVID-19 pandemic. Our study showed an association between household income level and the prevalence of mental illness in adolescents. Furthermore, the COVID-19 pandemic has exacerbated mental illness among adolescents from low household income level, underscoring the necessity for heightened public attention and measures targeted at this demographic.

Trends in socioeconomic inequality in e-cigarette use among adolescents in South Korea

INTRODUCTION

The global rise in e-cigarette use among adolescents is alarming, with associated socioeconomic inequalities posing potential public health risks. This study examined trends in the socioeconomic inequality in e-cigarette use among South Korean adolescents to inform future regulatory directions.

METHODS

Socioeconomic inequalities in e-cigarette use among Korean adolescents were assessed using data from the Korea Youth Risk Behavior Web-based Survey (KYRBS) from 2011 to 2023. The Concentration Index, a well-established method for measuring health inequalities, was employed. Additionally, this study investigated how the smoking behaviors of family members and friends influence socioeconomic inequality in e-cigarette use among Korean adolescents, using a decomposition analysis.

RESULTS

The Concentration Index values showed a clear, fluctuating downward trend over 13 years, from -0.12 (95% CI: -0.13 - -0.10) in 2011 to -0.24 (95% CI: -0.26 - -0.21) in 2023. Decomposition analysis revealed that smoking among peer groups, including friends and siblings, was the primary contributor to socioeconomic inequality in e-cigarette use, followed by maternal smoking.

CONCLUSIONS

Socioeconomic inequalities in adolescent e-cigarette use in South Korea are widening, particularly among low socioeconomic status groups. The impact of peer groups on socioeconomic inequalities in e-cigarette use among adolescents is concerning.

National Trends in the Prevalence of Self-Perceived Overweight Among Adolescents Between 2005 and 2022: Nationwide Representative Study

BACKGROUND

Despite several studies on self-evaluation of health and body shape, existing research on the risk factors of self-perceived overweight is insufficient, especially during the COVID-19 pandemic.

OBJECTIVE

This study aims to identify the risk factors affecting self-perceived overweight and examine how the prevalence of self-perceived overweight has changed before and during the COVID-19 pandemic. Specifically, we analyzed the impact of altered lifestyles due to COVID-19 on this phenomenon.

METHODS

The data used in the study were obtained from middle and high school students who participated in the Korean Youth Risk Behavior Web-based Survey (N=1,189,586). This survey was a 2-stage stratified cluster sampling survey representative of South Korean adolescents. We grouped the survey results by year and estimated the slope in the prevalence of self-perceived overweight before and during the pandemic using weighted linear regression, as well as the prevalence tendencies of self-perceived overweight according to various risk factors. We used prevalence ratios to identify the risk factors for self-perceived overweight. In addition, we conducted comparisons of risk factors in different periods to identify their associations with the COVID-19 pandemic.

RESULTS

The prevalence of self-perceived overweight was much higher than BMI-based overweight among 1,189,586 middle and high school participants (grade 7-12) from 2005 to 2022 (female participants: n=577,102, 48.51%). From 2005 to 2019 (prepandemic), the prevalence of self-perceived overweight increased (β=2.80, 95% CI 2.70-2.90), but from 2020 to 2022 (pandemic) it decreased (β=-0.53, 95% CI -0.74 to -0.33). During the pandemic, individuals with higher levels of stress or lower household economic status exhibited a more substantial decrease in the rate of self-perceived overweight. The prevalence of self-perceived overweight tended to be higher among individuals with poor academic performance, lower economic status, poorer subjective health, and a higher stress level.

CONCLUSIONS

Our nationwide study, conducted over 18 years, indicated that self-perceived overweight decreased during the COVID-19 period while identifying low academic performance and economic status as risk factors. These findings suggest the need for policies and facilities to address serious dieting and body dissatisfaction resulting from self-perceived overweight by developing counseling programs for adolescents with risk factors such as lower school performance and economic status.

Sex Differences in Risk Factors for Generalized Anxiety Disorder in Korean Adolescents

Objectives

This study aimed to examine sex differences in the risk factors associated with generalized anxiety disorder (GAD) among Korean adolescents to provide insights for drafting more effective prevention strategies.

Methods

Data from 51845 middle and high school students in the 18th Korea Youth Risk Behavior Web-based Survey were analyzed. GAD was assessed using the 7-item Generalized Anxiety Disorder tool, and factors such as grade, academic performance, economic status, living arrangements, smoking, drinking, sexual experience, and physical activity were included. The prevalence of GAD and its association with these factors were compared between male and female students using chi-square tests and logistic regression. Odds ratios were compared statistically to identify sex-specific differences.

Results

GAD prevalence was higher among girls (42.1%) than boys (30.1%). Both sexes showed increased GAD risk with lower academic performance, lower economic status, smoking, drinking, and sexual experience. Boys living apart from their families had a higher GAD risk, but this was not significant for girls. Additionally, smoking and drinking were associated with a higher increase in GAD risk in girls than in boys.

Conclusion

This study underscores the importance of considering sex differences in the prevention of GAD among adolescents. Tailored sex-specific interventions are crucial for effective prevention and management of GAD in Korean adolescents.

Interaction of sexual violence perpetration and victimization on suicide attempts in Korean adolescents on additive and multiplicative scales: a population-based cross-sectional study

PURPOSE

To evaluate the associations and interaction between sexual violence perpetration and victimization on suicide attempts using a large representative sample of adolescents from South Korea.

METHODS

Based on data from 515,247 adolescents aged 12-18 years from the Korea Youth Risk Behavior Web-Based Survey (2006-2012), a nationally representative repeated cross-sectional survey, we obtained self-reports of suicide attempts over the past year and of lifetime sexual violence perpetration and victimization. Using complex survey weights, weighted logistic regression models were employed to estimate the odds ratios (ORs). The interaction analyses were conducted on both additive and multiplicative scales. All analyses were conducted separately for boys and girls.

RESULTS

Lifetime prevalence of sexual violence perpetration were 1.3% for boys and 0.4% for girls, and about 40% of those perpetrating sexual violence were also victims. After adjusting for several covariates, sexual violence perpetration was independently associated with suicide attempts in boys (ORadjusted for boys 1.80 [95% confidence intervals: 1.53, 2.11]), whereas in girls, the association was only marginally significant (ORadjusted for girls 1.27 [1.00, 1.63]). We found the negative multiplicative and additive interaction between the sexual violence perpetration and victimization on suicide attempts for both boys and girls (the ratio of ORs 0.30 [0.23, 0.39] for boys and 0.20 [0.12, 0.31] for girls; relative excess risk due to interaction - 1.20 [-1.91, - 0.50] for boys and - 2.33 [-3.00, - 1.66] for girls).

CONCLUSION

Sexual violence perpetration and victimization were independently and interactively associated with suicide attempts in adolescents, with a sub-additive interaction found between these two variables. Public mental health services and policies should recognize the importance of actively involving adolescents who had sexually perpetrated others as key intervention targets.

The association between tooth brushing during lunchtime and obesity in South Korean adolescents

Obesity in adolescents is a global health concern associated with several diseases and complications in adulthood. Obesity has been reported to be strongly associated with oral habits. To investigate the association between tooth brushing during lunchtime and the prevalence of obesity among adolescents in a nationally representative sample of South Korean adolescents. Data from the 2018-2021 Korea Youth Risk Behavior Web-Based Survey were used in this cross-sectional study. Obesity was measured based on the body mass index. The chi-square test was used to investigate and compare tooth brushing habits during lunchtime in the study population, and multivariate logistic regression analysis was performed to analyze the relationship between tooth brushing during lunchtime and the prevalence of obesity. The odds of obesity were lower in the group that brushed their teeth during lunchtime (adjusted odd ratio: 0.90, 95% confidence interval: 0.88-0.93). Furthermore, the odds of obesity were significantly higher in high school students; boys; those with a low household income, low subjective health status awareness, medical history (asthma or atrophy), and history of sealant use; and those who responded after the coronavirus disease 2019 pandemic. A significant inverse relationship was found between tooth brushing habits during lunchtime and the prevalence of obesity. This relationship was consistent regardless of socioeconomic and lifestyle factors.

Changes in Daily life due to the COVID-19 Pandemic and Mental Health Status in Korean Adolescents

This study assessed the relationship between daily life changes and mental health in Korean adolescents during the COVID-19 pandemic. Data from middle and high school students who responded to the relevant survey items the 2021 Korea Youth Risk Behavior Survey were analyzed (n = 53,868). The survey assessed changes in economic status, physical activity, skipping breakfast, drinking, smoking, and mental health, including stress, depression, generalized anxiety disorder, and suicidal ideation, due to the COVID-19 pandemic. The overall prevalence of perceived stress, depression, generalized anxiety disorder, and suicidal ideation was 38.6%, 26.4%, 12.2%, and 12.4%. Adolescents whose economic status worsened due to COVID-19 had a higher risk of perceived stress, depression, generalized anxiety disorder, and suicidal ideation. Changes in physical activity and breakfast consumption due to the COVID-19 pandemic were significantly associated with increases in perceived stress, depression, generalized anxiety disorder, and suicidal ideation. Adolescents who increased their alcohol consumption had the highest risk of perceived stress, depression, generalized anxiety disorder, and suicidal ideation. Changes in economic status and health behaviors caused by the COVID-19 pandemic had a negative effect on the mental health of Korean adolescents. These results can be used to identify adolescents at high risk of developing mental health problems.

Unhealthy Weight Control Behaviors according to the Status of Combustible Cigarette and Noncombustible Nicotine or Tobacco Product Use among Korean Adolescents with Experience Attempting to Reduce or Maintain Their Body Weight: The 15th Korea Youth Risk Behavior Survey, 2019

BACKGROUND

Noncombustible nicotine or tobacco product (NNTP) use, and cigarette smoking are associated with a high likelihood of unhealthy weight control behaviors (UWCBs) among adolescents. However, no study has addressed the differences in UWCBs among non-users, single users of combustible cigarettes (CCs) or NNTPs and dual users. This study compared the frequencies of weight control behaviors according to the status of CC and NNTP use among Korean adolescents.

METHODS

This was a cross-sectional study of 25,094 adolescents who had attempted to reduce or maintain their body weight during the past 30 days, using data from the 15th Korea Youth Risk Behavior Survey, 2019. Data on the status of CC and NNTP use, weight status, and weight control behaviors were obtained using self-report questionnaires. Subjects were categorized into four groups: non-users, cigarette-only users, NNTP-only users, and dual users.

RESULTS

Among boys and girls, current smokers and NNTP users were 8.9%±0.3% and 5.5%±0.3%, and 4.2%±0.2% and 1.7%±0.1%, respectively. Among boys, NNTP-only users were more likely to engage in extreme weight control behaviors than non-users. Among girls, users of either CCs or NNTPs were more likely to engage in extreme weight control behaviors and less extreme weight control behaviors than non-users.

CONCLUSION

This study shows that users of either CCs or NNTPs are more likely to engage in UWCBs, and NNTP-only users are the most likely to do so.

Assessment of Epidemiological Data and Surveillance in Korea Substance Use Research: Insights and Future Directions

OBJECTIVES

Effective data collection and surveillance of epidemiological trends are essential in confronting the growing challenges associated with substance use (SU), especially in light of emerging trends and underreporting of cases. However, research and data are scarce regarding SU and substance use disorder (SUD) in Korea.

METHODS

We conducted a scoping review to identify data sources and surveillance methods used in SU research in Korea up to December 2023. This review was complemented by semi-structured consultations with experts in this area in Korea, whose feedback led to revisions of previously identified data sources and assessments.

RESULTS

Our review identified 32 publications conducting secondary analyses on existing data to examine the epidemiology of SU and SUD in Korea. Of these, 14 studies utilized clinical databases to explore the prescription patterns of addictive substances, particularly opioids. Eleven data sources showed promise for advancing SU research; however, they face substantial limitations, including a lack of available data, missing data, the absence of key variables, the exclusion of marginalized populations not captured within the clinical system, and complexities in matching individual-level data across time points and datasets.

CONCLUSIONS

Current surveillance methods for SU in Korea face considerable challenges in accessibility, usability, and standardization. Moreover, existing data repositories may fail to capture information on populations not served by clinical or judicial systems. To systematically improve surveillance approaches, it is necessary to develop a robust and nationally representative survey, refine the use of existing clinical data, and ensure the availability of data on treatment facilities.

Development and psychometric testing of a questionnaire for the Korea Youth risk behavior survey to assess physical activity behaviors

BACKGROUND

Physical activity is essential for physical, mental, and cognitive health. Providing evidence to develop better public health policies to encourage increased physical activity is crucial. Therefore, we developed an in-depth survey as part of the Korea Youth Risk Behavior Survey to assess the current status and determinants of physical activity among Korean adolescents.

METHODS

We developed an initial version of the questionnaire based on a review of validated questionnaires, recent trends and emerging issues related to adolescent physical activity, and the national public health agenda pertaining to health promotion. Content validity was confirmed by a panel of 10 experts. Face validity was confirmed through focus group interviews with 12 first-year middle school students. The test-retest reliability of the questionnaire was evaluated by administering it twice, approximately two weeks apart, to a sample of 360 middle and high school students. Additionally, the frequency or average number of responses was analyzed in a sample of 600 students who participated in the initial test-retest reliability evaluation of the questionnaire developed in this study.

RESULTS

Through item pool generation and content and face validity test, the final 15 questionnaire items were developed across five themes: levels of physical activity, school sports club activities, transportation-related physical activity, physical activity-promoting environments, and factors mediating physical activity. The test-retest reliability ranged from fair to substantial. Results from the newly developed survey reveal that only a minority of adolescents engage in sufficient physical activity, with only 17.2% and 21.5% participating in vigorous and moderate-intensity activities, respectively, for at least five days per week. Among school-based activities, 44.3% of students do not participate in school sports clubs due to reasons including absence of clubs and disinterest in exercise. The major motivators for physical activity are personal enjoyment and health benefits, whereas preferences for other leisure activities and academic pressures are the predominant barriers.

CONCLUSIONS

This study developed valid and reliable in-depth survey items to assess physical activity among Korean youths. It will hopefully enhance our understanding of adolescent physical activity, offering essential preliminary evidence to inform the development of public health strategies aimed at promoting adolescent health.

Perceived familial financial insecurity and obesity among Korean adolescents during the COVID-19 pandemic

BACKGROUND

In high-income countries, socioeconomically disadvantaged adolescents experience a higher risk of obesity, which may have been further exacerbated during the early phase of the COVID-19 pandemic. This study aimed to investigate the association between obesity and familial financial insecurity, utilizing data on subjective household socioeconomic status (SES) and perceived family-level financial deterioration induced by COVID-19.

METHODS

We utilized data from the Korea Youth Risk Behavior Survey, a nationally representative sample of Korean adolescents, in 2020 and 2021. The independent and joint associations of two primary exposures, subjective household SES and perceived family-level financial deterioration, with obesity were assessed using multivariable logistic regression models.

RESULTS

Among 106,979 adolescents aged 12-18 years, 16.9% of boys and 9.0% of girls met the criteria for obesity. Notably, 70.5% reported experiencing COVID-19-related financial deterioration. Both subjective household SES and perceived family-level financial deterioration independently and synergistically increased the odds of obesity. A graded association was observed between obesity and lower SES and more severe financial deterioration, particularly among girls. Younger adolescents were more sensitive to household SES, whereas older adolescents were more sensitive to financial deterioration.

CONCLUSIONS

While the COVID-19 pandemic presented a unique social context, our findings highlight that financially insecure adolescents were at an increased risk of obesity during the early phase of the pandemic. This underscores the need for obesity-prevention strategies in times of macroeconomic recession to address not only the persistent influence of household SES but also the direct and indirect effects of family-level financial deterioration.

Association of the COVID-19 lockdown with health risk behaviors in South Korean adolescents

Since there is no certainty about when the coronavirus disease 2019 (COVID-19) lockdown will be affected by health risk behaviors, so we investigate the effect of COVID-19-related health risk behavior changes using school-based self-reported data from a nationally representative South Korean adolescent population. We analyzed web-based self-reported data from the Korea Youth Risk Behavior Web-based Survey in 111,878 participants (57,069 in COVID-19 prepandemic); 54,809 in during the COVID-19 pandemic. This study included 12 to 18-year-olds. Self-report questionnaires were used to assess socioeconomic status, health risk behaviors, and psychological factors. Health risk behaviors such as alcohol consumption, substance use, and sexual experience significantly decreased in COVID-19 pandemic than in COVID-19 prepandemic. Psychosomatic changes such as stress levels, violence experience, depression, suicidal ideation, suicidal plans, and suicide attempts were significantly lower in COVID-19 pandemic compared to COVID-19 prepandemic (P < .001). After adjusting for multiple confounding variables, less alcohol consumption (odds ratio [OR] = 0.98; 95% confidence interval [CI] = 0.88-0.93), less exercise (OR = 0.92; 95% CI = 0.89-0.94), less sexual experience (OR = 0.82; 95% CI = 0.77-0.86), less violence experience (OR = 0.61; 95% CI = 0.55-0.67), less stress (OR = 0.86; 95% CI = 0.84-0.88), less depression (OR = 0.85; 95% CI = 0.83-0.88), less suicidal ideation (OR = 0.93; 95% CI = 0.89-0.97), plans (OR = 0.82; 95% CI = 0.76-0.88), attempts (OR = 0.78; 95% CI = 0.71-0.85) were significantly associated with the COVID-19 pandemic compared to COVID-19 prepandemic. The COVID-19 pandemic was associated with changes in health risk behaviors among Korean adolescents, resulting in alcohol drinking, sexual experience, drug use, violence experience, and suicidal behaviors (idea, plan, and attempts) being decreased during the lockdown period.

National prevalence of atopic dermatitis in Korean adolescents from 2009 to 2022

Previous studies have examined the prevalence of allergic diseases in adolescents 1-2 years after the emergence of the COVID-19 pandemic. However, more data is needed to understand the long-term impact of COVID-19 on allergic diseases. Thus, we aimed to examine the trend of the atopic dermatitis prevalence in Korean adolescents before and during the COVID-19 pandemic across 14 years. Additionally, we analyze the risk factors of atopic dermatitis (AD) based on the results. The Korean Disease Control and Prevention Agency conducted the Korea Youth Risk Behavior Web-based Survey from 2009 to 2022, from which the data for this study were obtained. Prevalence trends were compared across subgroups, and the β difference (βdiff) was calculated. We computed odds ratios to examine changes in the disease prevalence before and during the pandemic. This study included a total of 917,461 participants from 2009 to 2022. The prevalence of atopic dermatitis increased from 6.79% (95% CI 6.66-6.91) in 2009-2011 to 6.89% (95% CI 6.72-7.05) in 2018-2019, then decreased slightly to 5.82% (95% CI 5.60-6.04) in 2022. Across the 14 years, middle school student status, low parent's highest education level, low household income, non-alcohol consumption, non-smoker smoking status, no suicidal thoughts, and no suicide attempts were associated with increased risk of atopic dermatitis, while female sex, rural residence, high BMI, low school performance, low household income, and no feelings of sadness and despair was associated with a small increase. This study examined the prevalence of atopic dermatitis across an 18-year, and found that the prevalence increased in the pre-pandemic then decreased during the start of the pandemic and remained constant throughout the pandemic. This trend could be explained mainly by the large scale social and political changes that occurred during the COVID-19 pandemic.

Machine Learning-Based Prediction of Suicidal Thinking in Adolescents by Derivation and Validation in 3 Independent Worldwide Cohorts: Algorithm Development and Validation Study

BACKGROUND

Suicide is the second-leading cause of death among adolescents and is associated with clusters of suicides. Despite numerous studies on this preventable cause of death, the focus has primarily been on single nations and traditional statistical methods.

OBJECTIVE

This study aims to develop a predictive model for adolescent suicidal thinking using multinational data sets and machine learning (ML).

METHODS

We used data from the Korea Youth Risk Behavior Web-based Survey with 566,875 adolescents aged between 13 and 18 years and conducted external validation using the Youth Risk Behavior Survey with 103,874 adolescents and Norway's University National General Survey with 19,574 adolescents. Several tree-based ML models were developed, and feature importance and Shapley additive explanations values were analyzed to identify risk factors for adolescent suicidal thinking.

RESULTS

When trained on the Korea Youth Risk Behavior Web-based Survey data from South Korea with a 95% CI, the XGBoost model reported an area under the receiver operating characteristic (AUROC) curve of 90.06% (95% CI 89.97-90.16), displaying superior performance compared to other models. For external validation using the Youth Risk Behavior Survey data from the United States and the University National General Survey from Norway, the XGBoost model achieved AUROCs of 83.09% and 81.27%, respectively. Across all data sets, XGBoost consistently outperformed the other models with the highest AUROC score, and was selected as the optimal model. In terms of predictors of suicidal thinking, feelings of sadness and despair were the most influential, accounting for 57.4% of the impact, followed by stress status at 19.8%. This was followed by age (5.7%), household income (4%), academic achievement (3.4%), sex (2.1%), and others, which contributed less than 2% each.

CONCLUSIONS

This study used ML by integrating diverse data sets from 3 countries to address adolescent suicide. The findings highlight the important role of emotional health indicators in predicting suicidal thinking among adolescents. Specifically, sadness and despair were identified as the most significant predictors, followed by stressful conditions and age. These findings emphasize the critical need for early diagnosis and prevention of mental health issues during adolescence.

The residential, area-specific prevalence and associated factors of suicidal ideation among South Korean adolescents

Objectives

This study investigated the residential, area-specific prevalence and associated factors of suicidal ideation among adolescents in South Korea, based on nationally representative data.

Methods

A secondary analysis was performed using the database of the 17th Korean Youth Health Behavior Survey, which contained data from 54,848 adolescents.

Results

Female adolescents (more influential in counties), low economic status (more influential in metropolitan cities), perceived stress (more influential in metropolitan cities), depression (more influential in counties), loneliness (more influential in counties), and anxiety (more influential in counties) were influencing factors in all areas, and the factors associated with suicidal ideation differed by residential area. The factors related to suicidal ideation were similar by residential area, but the degree of relevance differed from area to area; in particular, the prevalence of variables related to mental health (depression, loneliness, and anxiety) was high in counties. Alcohol drinking was significant only in small- and medium-sized cities in terms of suicidal ideation.

Conclusion

Suicide prevention programs for adolescents should be implemented given the higher incidence of suicidal ideation among female adolescents, the greater influence of mental health-related variables in counties, and the influence of smoking in cities. There were differences in the prevalence and risk factors of suicidal ideation by residential areas.

Network Structure and Clustering Analysis Relating to Individual Symptoms of Problematic Internet Use in a Community Adolescent Population

INTRODUCTION

Problematic internet use (PIU) is a psychopathology that includes multiple symptoms and psychological constructs. Because no studies have considered both network structures and clusters among individual symptoms in the context of PIU in a Korean adolescent population, this study aimed to investigate network structures and clustering in relation to PIU symptoms in adolescents.

METHODS

Overall, 73,238 adolescents were included. PIU severity was assessed using a self-rating scale comprising 20 items and 6 subscales, namely, the Internet Addiction Proneness Scale for Youth-Short Form; KS scale. Network structures and clusters among symptoms were analyzed using a Gaussian graphical model and exploratory graph analysis, respectively. Centrality of strength, closeness, and betweenness scores was also calculated.

RESULTS

Our study identified four clusters: disturbance in adaptive functioning, virtual interpersonal relationships, withdrawal, and tolerance. The symptom of confidence served as a node bridging the cluster of virtual interpersonal relationships and other clusters of withdrawal and disturbances of adaptive function. The symptom of craving served as a bridge between the clusters of withdrawal and tolerance with high betweenness centrality.

CONCLUSION

This study identified network structures and clustering among PIU symptoms in adolescents and revealed that positive experiences derived from online interpersonal relationships were an important mechanism underlying PIU. These are novel insights concerning the interconnection among multiple symptoms and related clustering for the mechanism of adolescent PIU in terms of KS-scale PIU assessment.

National prevalence of smoking among adolescents at tobacco tax increase and COVID-19 pandemic in South Korea, 2005-2022

Prior research has predominantly focused on the overall effects of the tobacco tax increase and the COVID-19 pandemic on adolescent smoking behavior. However, there is a need to examine both the immediate and sustained associations of these two factors on subgroups of adolescents, employing an interrupted time-series model. We aimed to investigate the immediate and sustained association of tobacco tax increase and the COVID-19 pandemic on adolescent smoking prevalence. This study utilized data from the Korea Youth Risk Behavior Web-Based Survey to analyze the prevalence of current smoking among all participants (CSP) and the prevalence of daily smoking among current smokers (DSP) of Korean adolescents (n = 1,159,995; mean, age 14.99; male 51.5%) over 18 years from 2005 to 2022. The study examined 18-year trends in CSP and DSP among Korean adolescents, emphasizing the influences of the 2015 tobacco tax increase and the COVID-19 pandemic, using β coefficients and their differences (βdiff) from an interrupted time-series ARIMA model. While CSP exhibited a decreasing trend, DSP exhibited an increasing trend. Tobacco tax increase was associated with both the short and long terms in smoking prevalence, however, the short-term association on prevalence (CSP, - 3.076 [95% CI, - 3.707 to - 2.445]; DSP, - 4.112 [95% CI, - 6.488 to - 1.735]) was stronger. The pandemic was associated with an immediate increase in DSP (9.345 [95% CI, 5.285-13.406]). These effects were strongest among adolescents from low economic status and those exposed to familial secondhand smoking. Supportive programs for adolescents in low-income families will help overcome the effects associated with the pandemic. As a tobacco tax increase was associated with a reduction in smoking prevalence, this could be one method to overcome the effects of the pandemic.

Changes in Adolescent Health Behavior and the Exacerbation of Economic Hardship During the COVID-19 Pandemic: A Cross-sectional Study From the Korea Youth Risk Behavior Survey

OBJECTIVES

This study investigated the association between exacerbated economic hardship during the coronavirus disease 2019 (COVID-19) pandemic and changes in the health behaviors of Korean adolescents.

METHODS

We analyzed data from the 2021 Korea Youth Risk Behavior Survey and included 44 908 students (22 823 boys and 22 085 girls) as study subjects. The dependent variables included changes in health behaviors (breakfast habits, physical activity, and alcohol use) that occurred during the COVID-19 pandemic. The aggravation of economic hardship by COVID-19 and the subjective economic status of the family were used as exposure variables. Multiple logistic regression analysis was utilized to calculate the prevalence odds ratios (PORs).

RESULTS

Severe exacerbation of a family's economic hardship due to COVID-19 was negatively associated with the health behaviors of adolescents, including increased breakfast skipping (POR, 1.85; 95% confidence interval [CI], 1.55 to 2.21 for boys and POR, 1.56; 95% CI, 1.27 to 1.92 for girls) and decreased physical activity (POR, 1.37; 95% CI, 1.19 to 1.57 for boys and POR, 1.38; 95% CI, 1.19 to 1.60 for girls). These negative changes in health behaviors were further amplified when combined with a low subjective family economic status.

CONCLUSIONS

The experience of worsening household hardship can lead to negative changes in health behavior among adolescents. It is crucial to implement measures that address the economic challenges that arise from stressful events such as COVID-19 and to strive to improve the lifestyles of adolescents under such circumstances.

Decrease in household secondhand smoking among Korean adolescents associated with smoke-free policies: grade-period-cohort and interrupted time series analyses

OBJECTIVES

Smoke-free areas have expanded and related campaigns have been implemented since 1995 in Korea. As a result, household secondhand smoke (SHS) exposure has decreased over the past 15 years. We assessed the cohort effect, the effect of a 2008 campaign on household SHS exposure, and the impact of a complete smoking ban in public places along with increased penalties, as implemented in December 2011.

METHODS

Nationally representative cross-sectional 15-wave survey data of Korean adolescents were used. The 810,516 participants were classified into 6 grade groups, 15 period groups, and 20 middle school admission cohorts. An age-period-cohort analysis, conducted with the intrinsic estimator method, was used to assess the cohort effect of household SHS exposure, and interrupted-time series analyses were conducted to evaluate the effects of the smoke-free policy and the campaign.

RESULTS

For cohorts who entered middle school from 2002 to 2008, the risk of household SHS exposure decreased among both boys and girls. Immediately after implementation of the smoke-free policy, the prevalence of household SHS exposure by period decreased significantly for boys (coefficient, -8.96; p<0.05) and non-significantly for girls (coefficient, -6.99; p=0.07). After the campaign, there was a significant decrease in household SHS exposure by cohort among boys, both immediately and post-intervention (coefficient, -4.84; p=0.03; coefficient, -1.22; p=0.02, respectively).

CONCLUSIONS

A school-admission-cohort effect was found on household SHS exposure among adolescents, which was associated with the smoke-free policy and the campaign. Anti-smoking interventions should be implemented consistently and simultaneously.

Comparison of the responses of cross-sectional web- and paper-based surveys on lifestyle behaviors of Japanese adolescents

Objective

In Japan, paper-based surveys are currently more effective than web-based surveys. This study compared the response rates and lifestyle behaviors between paper- and web-based surveys conducted among Japanese junior and senior high schools.

Methods

In total, there were 42 and 64 junior and senior high schools, respectively, for the web-based surveys and 20 and 27 junior and senior high schools, respectively, for the paper-based surveys. The questionnaire covered lifestyle behaviors (e.g., alcohol consumption, smoking, exercise, eating, and sleep status), mental health, and plans to attend college. School- and student-level response rates by survey method were assessed, and so was the effect on the reporting of each lifestyle behavior using logistic regression models.

Results

The school response rates were 16.0% and 38.3% for web- and paper-based surveys, respectively. The student response rates were 88.7% and 77.2%, respectively. The web-based group had significantly more female participants and lower response rates for higher grades in senior high schools. The odds of lifetime and current alcohol consumption and poor mental health were lower, whereas those of lifetime use of conventional cigarettes, shorter sleep duration, and plans to continue attending college were higher among web-based (vs. paper-based) participants.

Conclusions

The school response rate was poor in the web-based survey. However, whether the differences in lifestyle behavior are attributed to selection bias or the survey method remains unclear.

Hand and Oral Hygiene Practices of South Korean Adolescents Before and During the COVID-19 Pandemic

Importance

Only a few studies have examined the long-term trends of hand and oral hygiene, especially among adolescents.

Objective

To investigate the 15-year trends in frequency of handwashing and toothbrushing and examine the factors associated with hand and oral hygiene, particularly during the COVID-19 pandemic.

Design, Setting, and Participants

This cross-sectional study, performed from January 1, 2008, to December 31, 2022, used general population-based data from 963 644 individuals in a national representative survey (Korea Youth Risk Behavior Web-based Survey [KYRBS]).

Exposure

COVID-19 pandemic.

Main Outcomes and Measures

Trends in hand and oral hygiene practices were measured by how frequently adolescents washed their hands and whether they fulfilled the recommended guidelines for toothbrushing. An interrupted time series analysis using linear and logistic regression models was performed to assess any associations with the COVID-19 pandemic. Hand and oral hygiene behaviors before and during the pandemic in each sociodemographic subgroup were also compared.

Results

In the 963 644 adolescents (495 697 [51.4%] male; mean [range] age, 15.01 [12-18] years) who participated in the KYRBS from 2008 to 2022, a 73.3% (95% CI, 59.4%-97.4%; P < .001) immediate increase was seen in overall hand hygiene behavior at the onset of the COVID-19 pandemic compared with the prepandemic period, with a sustained decrease thereafter (β = -0.018; 95% CI, -0.022 to -0.015; P < .001). Meanwhile, no immediate increase was observed in terms of overall oral hygiene behavior (0.1%; 95% CI, -0.9% to 1.1%; P = .82); however, there was a sustained decrease during the pandemic (β = -0.018; 95% CI, -0.020 to -0.016; P < .001). Older age, female sex, nonsmoking status, alcohol use, low household economic level, and poor school performance were significantly associated with poor hand hygiene during the pandemic.

Conclusions and Relevance

In this cross-sectional study of South Korean adolescents, an increase in the prevalence of hand hygiene was observed during the early pandemic; however, this prevalence decreased over time. Meanwhile, the decrease in the prevalence of oral hygiene was more pronounced during the pandemic. This study recommends stronger guidelines for adolescent health coaches, such as teachers or public health advisers, regarding hygiene behaviors, even after the COVID-19 pandemic ends.

A Comparison of Changes in Health Behavior, Obesity, and Mental Health of Korean Adolescents Before and During the COVID-19 Pandemic: Online Cross-Sectional Study

OBJECTIVE

The health behavior and mental health problems of adolescents have shown a variety of changes due to the coronavirus disease-2019 (COVID-19) pandemic. This study compared health behavior, obesity, and mental health among Korean adolescents before and during the early COVID-19 pandemic.

METHODS

Population-based and cross-sectional data from the 2019 and 2020 Korea Youth Risk Behavior Web-Based Surveys were used. Data of 57,048 and 54,948 adolescents from the 2019 and 2020 surveys, respectively, were compared. Multiple logistic regression analysis was conducted to compare health behavior, obesity, and mental health before and during the COVID-19 pandemic.

RESULTS

The adjusted odds ratio (aOR) of overweight, obesity, and body image perceived subjectively as fat, were higher in the 2020 sample compared to the 2019 sample. The aOR of the frequency (more than 3 times a week) of fast-food consumption was higher in 2020 than in 2019. However, the aOR of physical activity, alcohol use, and smoking experience were lower in 2020 than in 2019. In addition, during COVID-19, adolescents were less likely to have perceived severe stress, depressive moods, and suicidal ideation.

CONCLUSION

Current evidence suggests the co-occurrence of positive and negative changes in health behavior, obesity, and mental health among Korean adolescents during the early COVID-19 pandemic. The results contribute insights for monitoring adolescents' health behavior and promoting their mental health during school shutdowns.

Impact of Physical Activity on the Association Between Unhealthy Adolescent Behaviors and Anxiety Among Korean Adolescents: A Cross-sectional Study

OBJECTIVES

Adolescents who engage in unhealthy behaviors are particularly vulnerable to anxiety. We hypothesized that participation in physical activity could influence the relationship between anxiety and unhealthy behaviors in adolescents. These behaviors include smoking, alcohol consumption, and unsafe sexual activity.

METHODS

This study included 50 301 students from the first year of middle school to the third year of high school, all from Korea. The unhealthy adolescent behaviors examined included current alcohol consumption, current smoking, and unsafe sexual behavior. Anxiety levels were assessed using the Generalized Anxiety Disorder-7 questionnaire (GAD-7).

RESULTS

The participants had a mean age of 15.19 years and an average GAD-7 score of 4.23. No significant differences were observed in GAD-7 score among exercising participants when categorized by smoking status (p=0.835) or unsafe sexual behavior (p=0.489). In contrast, participants in the non-exercise group who engaged in these behaviors demonstrated significantly higher GAD-7 scores (p<0.001 and 0.016, respectively). The only significant interaction was found between unsafe sexual behavior and exercise (p=0.009). Based on logistic regression analysis, within the non-exercise group, significant positive associations were observed between current smoking and anxiety (odds ratio [OR], 1.36; 95% confidence interval [CI], 1.18 to 1.57), as well as between unsafe sexual behavior and anxiety (OR, 1.33; 95% CI, 1.02 to 1.73). However, within the exercise group, no significant association was found between anxiety and either smoking or unsafe sexual behavior. Furthermore, no significant interaction was observed between unhealthy behaviors and exercise.

CONCLUSIONS

These findings are insufficient to conclude that physical activity influences the relationship between unhealthy behaviors and anxiety.

Association between tobacco industry advertising expenses and tobacco advertising exposure among Korean adolescents

INTRODUCTION

Monitoring the activities and impacts of tobacco industries is vital for tobacco control. Based on tobacco industry financial statements and a nationally representative survey of Korean adolescents, we examined the association between tobacco industry commercial advertising expenses and advertising exposure among Korean adolescents.

METHODS

The commercial advertising expenses of three major tobacco industries in Korea (KT&G, Philip Morris Korea, and British and American Tobacco Korea) were identified in a repository (Data Analysis Retrieval and Transfer System) established by the Korean Financial Supervisory Service. The yearly advertising expenses were merged with data from the Korean Youth Risk Behavior Survey (2015-2018 and 2021, total N=309 190). We used logistic regression analyses to analyse the associations between tobacco industry advertising expenses and adolescent tobacco advertisement exposure.

RESULTS

In 2021, the total advertising expenses of the three companies exceeded US$260 million, and the proportion of Korean adolescents exposed to tobacco advertisements ranged from 65.9% to 78.7% during 2015-2018 and 2021. Higher advertising expense sizes were associated with the risk of exposure to tobacco advertisements in both girls and boys, with OR of 1.009 (95% CI (1): 1.008 to 1.010) and 1.010 (95% CI: 1.009 to 1.011), respectively.

CONCLUSION

Tobacco industry advertising expenses are associated with tobacco marketing exposure among adolescents. We used financial data to identify the reach of tobacco advertising among Korean adolescents. It is essential to increase tobacco industry surveillance using various data sources and to regulate tobacco advertising more strongly.

Factors associated with the adoption of extreme weight control behavior by non-obese adolescents: a secondary analysis

BACKGROUND

Misperceptions about obesity is common among adolescents. Adolescents who overestimate their body size tend to indulge in extreme weight control behaviors. However, little is known about the factors involved in the adoption of extreme weight control behavior (EWCB) by non-obese adolescents who are mistaken for being overweight. This study identified factors associated with unhealthy behaviors among normal/underweight high school students who overestimate their body image and attempt to lose weight.

DESIGN

A secondary analysis of nationally representative data from the Korea Youth Risk Behavior Survey focused on adolescents who attended vocational and academically oriented high schools.

METHODS

The analysis included data from 4,286 non-obese respondents (15-18 years) who overestimated their body weight. Of them, 2,887 were girls (66.5%), while 1,399 were boys (33.5%). Multiple logistic regression was used to investigate risk factors for EWCB by sex. A statistical analysis reflecting strata, clusters, and weights of the complex sampling design was adopted.

RESULTS

Of the respondents, 674 (23.3%) girls and 162 (11.5%) boys reported EWCB. For both sexes, vocational high school attendance and depression were significantly influenced by EWCB. EWCB was linked to perceived stress in girls and living in a big city in boys.

CONCLUSIONS

The findings suggest the importance of providing quality health education, including that for non-obese adolescents, in school obesity prevention programs along with the expansion of tailored intervention programs based on sex, following a consideration of the characteristics of high schools as well as individuals.

Trends in adolescent secondhand smoke exposure at home over 15 years in Korea: Inequality by parental education level

INTRODUCTION

Low parental education level and parental smoking are major risk factors for household secondhand smoke (SHS) exposure among adolescents. We investigated the trend in household SHS exposure according to sex, school, and parental education level to determine whether the decline in household SHS exposure over time depends on parental education level.

METHODS

We used cross-sectional Korea Youth Risk Behavior datasets (2006-2020; 806829 subjects were eligible). We applied binary logistic regression to assess household SHS exposure trends and evaluated the interaction between period and parental education level.

RESULTS

Household SHS exposure over 15 years has declined. The difference (0.121) was the smallest for male middle school students with low-educated parents. The slope for the estimated probability of household SHS exposure among students with high-educated parents was steeper than that for those with low-educated parents, except for female high school students (difference=0.141). Students with low-educated parents were at higher risk of household SHS exposure (male middle school students, adjusted odds ratio, AOR=1.52; 95% CI: 1.47-1.56; male high school students, AOR=1.42; 95% CI: 1.38-1.47; female middle school students, AOR=1.62; 95% CI: 1.58-1.67; female high school students, AOR=1.62; 95% CI: 1.57-1.67). The interaction between parental education level and period was significant. We also found a significant interaction between parental education level and parental smoking (other × present interaction, AOR=0.64; 95% CI: 0.60-0.67; low-low × present interaction, AOR=0.89; 95% CI: 0.83-0.95).

CONCLUSIONS

Changes in parental education level over time mainly contributed to changes in adolescents' household SHS exposure. Adolescents with low-educated parents were at higher risk of household SHS exposure, with a slower decline. These gaps must be considered when creating and implementing interventions. Campaigns and community programs to prevent household SHS need to be emphasized among vulnerable adolescents.

Trends in socioeconomic inequalities in obesity among Korean adolescents: the Korea Youth Risk Behavior Web-based Survey (KYRBS) 2006 to 2020

OBJECTIVES

This study investigated recent trends in the prevalence of obesity among Korean adolescents and explored socioeconomic disparities in obesity.

METHODS

This study used annual self-reported data on height, weight, and socioeconomic information from the Korea Youth Risk Behavior Web-based Survey from 2006 to 2020. With a 95.8% response rate, the sample consisted of 818,210 adolescents. Obesity prevalence was calculated according to 4 socioeconomic indicators (household income, father's educational attainment, mother's educational attainment, and urbanicity). Socioeconomic inequality was quantified using the relative index of inequality (RII).

RESULTS

The overall prevalence of obesity increased, doubling from 5.9% in 2006 to 11.7% in 2020. Boys and high school students showed a higher prevalence. The RIIs in household income and parental educational attainments significantly increased with time, indicating a growing inequality in obesity. Socioeconomic disadvantages had a greater influence on obesity among girls. The most recent RII values for boys were 1.25 for income, 1.79 for the father's education, and 1.45 for the mother's education, whereas the corresponding values for girls were 2.49, 3.17, and 2.62, respectively.

CONCLUSIONS

These findings highlight growing inequalities in adolescent obesity according to household income and parental educational attainments, especially for girls and middle schoolers.

Changes in mental health of Korean adolescents before and during the COVID-19 pandemic: a special report using the Korea Youth Risk Behavior Survey

OBJECTIVES

We aimed to study the effects of the coronavirus disease 2019 (COVID-19) pandemic on adolescents' mental health in Korea.

METHODS

We used data from the Korea Youth Risk Behavior Survey 2018-2021 with 227,139 students aged 12-18 years. We estimated the differences in depressive symptoms, suicidal ideation, and stress perception before (2018-2019) and during (2020-2021) the pandemic, as well as before (2019), the first year (2020) of, and the second year (2021) of the pandemic. We also examined whether COVID-19 is statistically associated with mental health.

RESULTS

In both male and female adolescents, the prevalence of depressive symptoms, suicidal ideation, and stress perception was higher in the "not living with family," "low household economic status," and "self-rated unhealthy status" subgroups. The prevalence of depressive symptoms and stress perception was higher in middle school students. Adolescents were less likely to experience depressive symptoms (adjusted odds ratio [aOR], 0.86; 95% confidence interval [CI], 0.83 to 0.89), suicidal ideation (aOR, 0.80; 95% CI, 0.76 to 0.83), and stress perception (aOR, 0.76; 95% CI, 0.74 to 0.79) in 2020 than in 2019. However, there were more depressive symptoms (aOR, 1.06; 95% CI, 1.02 to 1.09), suicidal ideation (aOR, 1.15; 95% CI, 1.10 to 1.21), and stress perception (aOR, 1.19; 95% CI, 1.16 to 1.23) in 2021 than in 2020.

CONCLUSIONS

The COVID-19 pandemic had positive impacts on mental health of adolescents in its early stages but has had negative impacts as the pandemic continues. Attention should be paid to adolescents who are particularly vulnerable to the mental health effects of the pandemic.

Self-reported physical activity behaviors of childhood cancer survivors: comparison to a general adolescent population in Korea

PURPOSE

Adequate physical activity (PA) can significantly contribute to the prevention of undesirable health outcomes in childhood cancer survivors (CCS). This study aimed to identify the patterns of PA and related factors in Korean CCS.

METHODS

Study subjects were 184 adolescents selected from an ongoing cohort study of Korean CCS and 1,840 sex- and school grade-matched controls randomly selected from the participants of the 2019 Korea Youth Risk Behavior Web-based Survey. Information on PA and sedentary behaviors was collected by self-administered questionnaire. We estimated body mass index (BMI)-adjusted odds ratio (OR) and 95% confidence interval (CI) for the advisable healthy behaviors of CCS compared with healthy controls using conditional logistic regression analysis. In addition, the associations of advisable healthy behaviors of CCS with sociodemographic and clinical factors were estimated using multiple logistic regression analysis.

RESULTS

CCS were less likely to be physically active than controls, but this finding was evident only in males. The ORs (95% CIs) for regular exercise, moderate intensity PA, vigorous intensity PA, and walking were 0.42 (0.27-0.65), 0.39 (0.24-0.63), 0.53 (0.33-0.84), and 0.64 (0.42-0.98), respectively, in male CCS compared with same-sex controls. Compared with same-sex controls, male CCS were 4.60 times and female survivors were 15.19 times more likely to sleep longer than 8 h a day. Among CCS, males were 2.92 times and 3.07 times more likely to perform moderate intensity PA and muscle-strengthening exercise, respectively, than female. Higher BMI (OR: 1.16), highest family income (OR: 3.98), and a caregiver who performed regular exercise (OR: 2.08) were positively associated with vigorous intensity PA of CCS. With increasing time after treatment completion, the probability of engaging in sedentary activity for less than 6 h per day decreased (OR = 0.89, 95% CI 0.79-1.00).

CONCLUSION

Korean adolescent CCS were physically inactive compared with control adolescents. Several sociodemographic factors such as sex, family income, caregiver PA, and obesity level were associated with PA behaviors of CCS.

IMPLICATIONS

Strategic effort would be needed to increase physical activity of childhood cancer survivors in adolescent period with consideration of various sociodemographic factors found in this study.

Associations of only-child status with health outcomes and risky behaviors in Korean middle- and high-school students: An outcome-wide analysis

The proportion of children who are the only child in the family are increasing. Several associations between only-child status and health outcomes or risky behaviors have been identified, but no study has explored associations across a wide range of outcomes in a single study. We used the 2019 Korea Youth Risk Behavior Survey, a nationwide cross-sectional survey of 57,303 middle and high school students, to perform an outcome-wide analysis on six health outcomes and risky behaviors, i.e. alcohol use, asthma, body mass index, sexual activity, smoking, and suicide attempt. Individual multivariable logistic regression models examined associations between single-child status and each outcome or behavior. Of the eligible 38,211 students, 5,334 students (14.0 %) were the only child in their family, while 32,877 students (86.0 %) had siblings. Of the six selected outcomes and behaviors, alcohol use (aOR 0.88, 95 % CI 0.82-0.94), asthma (aOR 1.22, 95 % CI 1.10-1.35) and sexual activity (aOR 1.16, 95 % CI 1.02-1.31) were significantly associated with only-child status. Thus, being the only child among South Korean adolescents is both a potential protective factor and risk factor for different health outcomes and behaviors. Future research is warranted to corroborate these findings and identify mechanisms, which could provide evidence for reducing adverse outcomes and behaviors in adolescents.

Physical activity in the era of climate change and COVID-19 pandemic: Results from the South Korea's 2022 Report Card on physical activity for children and adolescents

Background

With intensifying air pollutant levels and the COVID-19 pandemic, physical inactivity of South Korean children and adolescents may be threatened. Therefore, monitoring and surveillance of physical activity (PA) and relevant indicators are important for policy making pertaining to health promotion. Report Card is a third comprehensive evaluation of PA-related behaviors among and the sources of influence for South Korean children and adolescents.

Purpose

To provide the outcome of the South Korea's 2022 Report Card on PA for children and adolescents.

Methods

Based on a variety of sources including national surveys collected pre- and during-COVID-19 and information collected from government webpages, 11 indicators were graded by a committee of experts informed by the best available evidence. Data from during-COVID-19 were available for Overall PA, Sedentary Behavior, and Sleep and considered together in generating the overall grades.

Results

Grades were assigned to behavioral indicators (Overall PA: D-; Active Transportation: B+; Sedentary Behavior: D; Sleep: F) and sources of Influence (Family and Peers: C-; School: A; Community and Environment: B-; Government: A). Organized Sport and PA, Active Play, and Physical Fitness could not be graded due to the lack of data. The results largely indicated that children and adolescents show unfavorable behavioral grades even with favorable grades observed for the sources of influence indicators. Trivial differences were observed pre- and during-pandemic for Overall PA (≥60 min of MVPA for ≥4 d/wk: 20.8% vs 19.9%) and Sleep (met age-specific recommendation: 14.1% vs 15.0%); however, a marked increase in Sedentary Behavior was observed (≤2 h/d screen time: 28.8% vs 20.1%). A stark weekday vs weekend difference was observed in sleep duration. In terms of PA related sources of influence, high accessibility to PA facilities (81.1%) and high satisfaction of neighborhood public transit (74.6%) and safety (80.7%) were well reflected in our Active Transportation grade (B+). Nonetheless, perception of green environments including outdoor air quality (44.0%), noise (39.6%) and green space (56.5%) showed lower scores, suggesting that new barriers to active lifestyles are emerging for South Korean children and adolescents. Gender differences were also observed for overall PA (≥60 min of MVPA for ≥4 d/wk: 29.1% for boys vs 11.3% for girls) and sleep (met age-specific recommendations: 17.3% for boys vs 11.4% for girls), but not for sedentary behavior (≤2 h/d screen time: 26.4% for boys and 24.9% for girls).

Conclusions

Government and school policies/programs and the built environment are, in general, conducive to physically active lifestyles for South Korean children and adolescents; however, behavioural indicators received poor grades except for Active Transportation. A thorough evaluation of policies/programs at government, local, and school levels is needed to ensure that the efforts to have PA-enhancing infrastructure and systems are actually being translated into the behavior of children and adolescents in South Korea. Furthermore, improving PA surveillance, monitoring, and advocacy to ultimately establish healthy lifestyle patterns among children and adolescents is a top priority.

Factors affecting the use of herbal medicines for weight loss in overweight and obese adolescents

Objectives

Herbal medicine (HM) is widely used to treat obesity in adolescents worldwide since the currently available interventions have low compliance and lack long-term effects and safety data. This study aimed to analyze the factors affecting HM use for weight loss in overweight and obese adolescents.

Methods

A total of 46,336 adolescents were included in this cross-sectional study based on the Korea Youth Risk Behavior Web-Based Survey. Three models of HM use for weigh loss were developed by sequentially adding predisposing, enabling, and need factors according to Andersen's model using multiple logistic regression analyses considering the complex sampling design.

Results

Male and female high school students and students from low perceived household economic status were less likely to use HM for weight loss. Students whose fathers had a college degree or higher, depressed mood, and two or more chronic allergic diseases were more likely to use HM. Male students who perceived their body image as fat or very fat tended to use HM less than those who perceived their body image as very thin, thin, or moderate. Obese female students tended to use HM more than overweight female students.

Conclusion

These results can be used as the bases to promote HM use, provide ideas for future research, and strengthen the health insurance coverage extension for weight loss interventions.

Health-Related Behaviors and Psychological Status of Adolescent Patients with Atopic Dermatitis: The 2019 Korea Youth Risk Behavior Web-Based Survey

OBJECTIVE

Atopic dermatitis (AD) is one of the common chronic diseases that occur in children and adolescents as a chronic relapsing pruritic inflammatory skin disease. This study investigated how AD is associated with stress and depressive symptoms in a large representative sample of adolescents in South Korea.

METHODS

The Korea Youth Risk Behavior Web-based Survey 2019 was used in this study (n = 57,069, weighted national estimates = 2,672,170). Multivariate logistic regression was used to determine significant associations between AD and mental health, measured by stress and depressive symptoms. Sub-group analysis was also conducted using various socio-economic variables.

RESULTS

Among the present sample, 6.5% of adolescents (n = 173,909) were diagnosed with AD in the past 12 months. After adjusting for other variables, AD diagnosis was associated with significantly higher odds of experiencing stress (OR = 1.43) and depressive symptoms (OR = 1.32) as compared to adolescents without AD. A similar trend is found in subgroup model analysis using socio-economic variables (ie, education levels, parent's income levels, and residence area). Specifically, female adolescents with AD, adolescents of low socio-economic status, those reporting smoking and drinking experience, and who do not participate in regular physical activity are more vulnerable to stress and depressive symptoms.

CONCLUSION

This is a noteworthy finding because it denotes that AD may lead to negative outcomes, like depressive symptoms or stress, which could be prevented if suspected early.

Introduction of Child and Adolescent Mental Health Services in Korea and Their Role During the COVID-19 Pandemic: Focusing on the Ministry of Education Policy

This study aimed to discuss mental health services for children and adolescents that are being implemented as initiatives of the Korean government and to review the functions and roles of these projects during the COVID-19 pandemic. Three government departments are in charge of providing mental health services for children and adolescents: Ministry of Education, Ministry of Gender Equality and Family, and Ministry of Health and Welfare. The Ministry of Education has implemented several policies to facilitate the early detection of mental health issues among school students (from preventive interventions to selective interventions for high-risk students). The Ministry of Gender Equality and Family additionally serves out-of-school children and adolescents by facilitating early identification of adolescents in crises and providing temporary protection or emergency assistance (as required) through the Community Youth Safety-Net Project. Furthermore, the Ministry of Health and Welfare operates relevant mental health agencies for individuals of all ages including children and adolescents. Any high-risk students who have been screened through the projects of the Ministry of Education are supported through referrals to the following institutions for appropriate treatment of their symptoms: specialized hospitals, the Youth Counseling and Welfare Center operated by the Ministry of Gender Equality and Family, the National Youth Healing Center, the Mental Health Welfare Center operated by the Ministry of Health and Welfare, the Suicide Prevention Center, and the Child Welfare Center. To assist students who are facing any psychological difficulties because of the COVID-19 pandemic, the Ministry of Education has established a psychiatric support group for providing emergency mental health care; furthermore, schools are promoting psychological surveillance (e.g., provision of non-face-to-face counseling services that are centered around the Wee Center). The Ministry of Education, Ministry of Gender Equality and Family, and Ministry of Health and Welfare have provided varied mental health support services in order to address the challenges faced by children and adolescents during the pandemic. Nevertheless, the mental health services operated by each ministry do show some limitations because their service provision system is insufficiently collaborative. The present study discussed the positive effects of each initiative as well as its limitations; furthermore, it suggested improvements for facilitating the healthy development of children and adolescents' mental health.

Prediction Models for Suicide Attempts among Adolescents Using Machine Learning Techniques

OBJECTIVE

Suicide attempts (SAs) in adolescents are difficult to predict although it is a leading cause of death among adolescents. This study aimed to develop and evaluate SA prediction models based on six different machine learning (ML) algorithms for Korean adolescents using data from online surveys.

METHODS

Data were extracted from the 2011-2018 Korea Youth Risk Behavior Survey (KYRBS), an ongoing annual national survey. The participants comprised 468,482 nationally representative adolescents from 400 middle and 400 high schools, aged 12 to 18. The models were trained using several classic ML methods and then tested on internal and external independent datasets; performance metrics were calculated. Data analysis was performed from March 2020 to June 2020.

RESULTS

Among the 468,482 adolescents included in the analysis, 15,012 cases (3.2%) were identified as having made an SA. Three features (suicidal ideation, suicide planning, and grade) were identified as the most important predictors. The performance of the six ML models on the internal testing dataset was good, with both the area under the receiver operating characteristic curve (AUROC) and area under the precision-recall curve (AUPRC) ranging from 0.92 to 0.94. Although the AUROC of all models on the external testing dataset (2018 KYRBS) ranged from 0.93 to 0.95, the AUPRC of the models was approximately 0.5.

CONCLUSION

The developed and validated SA prediction models can be applied to detect high risks of SA. This approach could facilitate early intervention in the suicide crisis and may ultimately contribute to suicide prevention for adolescents.

Effect of Increased Depressive Feelings during the COVID-19 Pandemic on the Association between Depressive Mood and Suicidal Behavior: Using the 17th (2021) Korea Youth Risk Behavior Web-Based Survey (KYRBS)

This study investigated the impact of increased depressive feelings during the COVID-19 pandemic on the suicidal behavior of Korean high school students using the 17th Korea Youth Risk Behavior Web-Based Survey (KYRBS). We classified the independent variables into four groups ("no depressive mood and no increase in depressive feelings [group A]", "no depressive mood and increase in depressive feelings [group B]", "depressive mood and no increase in depressive feelings [group C]", and "depressive mood and increase in depressive feelings [group D]"). Compared to group A, group D showed an odds ratio of 18.30 in men and 14.87 in women for suicidal behavior after accounting for demographic and health behavioral characteristics. We found that depressive mood and a relatively short-term increase in depressive feelings had a synergistic effect, rather than an additive one, on suicidal behavior. Based on this result, we claim that an appropriate intervention method is necessary to prevent adolescents' depressive mood from developing into suicidal behavior during the pandemic.

Association between exposure to particulate matter and school absences in Korean asthmatic adolescents

Background

Because particulate matter (PM) and asthma are closely related, the prevalence of school absence among adolescents with asthma can be affected by the concentration of PM. We aimed to investigate the relationship between school absences due to asthma and the total number of days that the PM concentration exceeded the standard.

Methods

We used the data from the 16th Korea Youth Risk Behavior Survey and the PM levels of 17 metropolitan cities and provinces gathered from the AirKorea. Information on the characteristics of asthmatic adolescents and the prevalence of school absence was obtained using a questionnaire, while the PM levels based on the total number of days with poor and very poor PM grades were collected from the AirKorea website. Both χ² test and logistic regression analysis were performed using the weights presented in the original dataset.

Results

In the case of particulate matter of 10 microns in diameter or smaller (PM₁₀), the odds ratio (OR) after adjusting for confounders (sex, school year, body mass index, smoking history, diagnosis of allergic rhinitis, diagnosis of atopic dermatitis and city size) was 1.07 (95% confidence interval [CI]: 1.01–1.13) for absents due to asthma when the total days of poor and very poor grades of PM₁₀ (81 μg/m³ or higher) increased by 1 day. In the analysis of particulate matter of 2.5 microns in diameter or smaller (PM_2.5), the OR after adjusting for confounders was 1.01 (95% CI: 1.00–1.03) for absents due to asthma when the total number of days with poor and very poor PM_2.5 grades (36 μg/m³ or higher) increased by 1 day.

Conclusions

A significant association was observed between the total number of days of poor and very poor PM₁₀ and PM_2.5 grades and school absence due to asthma; PM can cause asthma exacerbation and affect the academic life.

Short- and Long-Term Impacts of the COVID-19 Pandemic on Suicide-Related Mental Health in Korean Adolescents

This study investigated the short-term (in 2020) and long-term (in 2021) impacts of the COVID-19 pandemic on suicide-related characteristics in Korean adolescents in comparison with the pre-pandemic period (in 2019) and examined the factors associated with those impacts. Secondary data of the cross-sectional 15th-17th (2019-2021) Korea Youth Risk Behavior Web-based Survey targeting adolescents in school were utilized. The proportions of adolescents with depression, suicidal ideation, suicide planning, and suicide attempts were 26.5%, 12.2%, 3.7%, and 2.4%, respectively. Following an adjustment, depression, suicidal ideation, and suicide attempts significantly improved in the short term and depression and suicide attempts improved significantly in the long term (i.e., 2021), albeit to a lesser degree. The associated variables in the short-term analysis (i.e., 2020) reflected the socioeconomic vulnerabilities (e.g., lower household socioeconomic status [SES], unhealthy status, and unhealthy behaviors), as well as the socioeconomically favorable indicators (e.g., high household SES and high academic achievement). In the long-term, suicidal ideation was no longer associated with a lack of engagement in hand washing, and suicide attempts were no longer associated with the amount of internet time used for studying. For a successful suicide prevention, it is necessary to develop in-school interventions that address the relevant factors identified in this study and the community-based interventions that target out-of-school adolescents.

Family economic hardship and adolescent mental health during the COVID-19 pandemic

Objective

This study examined whether pandemic related family economic hardships influenced adolescents' mental health during the COVID-19 pandemic in Korea.

Methods

Data were collected from 54,948 adolescents who participated in the 2020 Korea Youth Risk Behavior Web-Based Survey. We performed a multiple logistic regression analysis to examine the association between family economic hardship and mental health (anxiety, depressive symptoms, and suicidal ideation).

Results

Among the adolescents, 39.7, 24.7, and 5.9% reported slight, moderate, and severe economic hardship, respectively. COVID-19 related family economic hardship was significantly associated with higher odds of adolescents reporting anxiety, depressive symptoms, and suicidal ideation. This association was stronger among adolescents with low to middle family economic status.

Conclusions

This study suggests that adolescents from more economically vulnerable families are likely to be at a higher risk for long-term mental health effects due to the financial consequences of the COVID-19 pandemic.

The Impact of Household Economic Deterioration Caused by the COVID-19 Pandemic and Socioeconomic Status on Suicidal Behaviors in Adolescents: A Cross-sectional Study Using 2020 Korea Youth Risk Behavior Web-based Survey Data

OBJECTIVES

Economic hardship has a serious impact on adolescents' mental health. The financial impact of the coronavirus disease 2019 (COVID-19) pandemic was more severe for low-income families, and this also impacted adolescents. This study aimed to examine the associations of economic deterioration (ED) caused by the COVID-19 pandemic and low socioeconomic status (SES) with adolescents' suicidal behaviors.

METHODS

This study analyzed data from the 2020 Korea Youth Risk Behavior Web-based Survey, which included 54 948 middle and high school students. Odds ratios (ORs) of suicidal ideation, suicidal planning, and suicide attempts related to ED and SES were calculated using multivariable logistic regression. We calculated relative excess risks due to interaction to assess additive interactions.

RESULTS

The ORs for suicidal ideation, suicidal planning, and suicide attempts related to combined severe ED and low SES were 3.64 (95% confidence interval [CI], 3.13 to 4.23), 3.88 (95% CI, 3.09 to 4.88), and 4.27 (95% CI, 3.21 to 5.69), respectively.

CONCLUSIONS

ED and low SES were significantly associated with suicidal behaviors in adolescents. Although no significant additive interaction was found, the ORs related to suicidal ideation, suicidal planning, and suicide attempts were highest among adolescents from low-income families with severe ED. Special attention is needed for this group, considering the increased impact of economic inequality due to the COVID-19 pandemic.

Sleep and Mental Health Among Adolescents During the COVID-19 Pandemic

OBJECTIVE

This study aimed to investigate the association of sleep with mental health among Korean adolescents during the coronavirus disease (COVID-19) pandemic.

METHODS

Using data from the 16th Korea Youth Risk Behavior Web-Based Survey (2020) of 46,475 adolescents, we examined sleep duration and satisfaction and examined mental health for depressive symptoms, anxiety, and suicidal ideation. The data were analyzed using complex sample descriptive statistics and a multiple logistic regression model.

RESULTS

In 2020, the average sleep duration was 6.3 hours, and the sleep satisfaction rate was 30.8%. Depressive symptom and suicidal ideation rates were 24.2 and 10.3, respectively. These values are slightly better than those previously reported, before COVID-19. However, poor sleep was still associated with mental health. The likelihood of mental health problems was higher among those who slept for six hours or less than for those who slept for eight hours or more (p<0.05). Additionally, the results showed that the lower the sleep satisfaction, the higher the likelihood of mental health problems (p<0.05).

CONCLUSION

Even after the COVID-19 outbreak, poor sleep associated with mental health problems remained as high as before the outbreak of COVID-19.

Relationship between Smartphone Addiction and Sleep Satisfaction: A Cross-Sectional Study on Korean Adolescents

The purpose of this study was to analyze the relationship between smartphone addiction and sleep satisfaction in 54,948 Korean adolescents. This study utilized the Korea Youth Risk Behavior Web-Based Survey (KYRBS). The dependent variable was sleep satisfaction. Independent variables were smartphone addiction level and usage time. Gender, school grade, stress, depression, regular physical activity (PA), asthma, allergic rhinitis, and atopic dermatitis were selected as confounding variables. A chi-squared test, logistic regression, and independent t-test were performed for data analysis. As a result of the chi-squared test, sleep satisfaction showed significant relationships with all confounding variables (all p < 0.001). As a result of adjusting all confounding variables, sleep satisfaction of smartphone normal users was significantly higher (odds ratios: 1.372, p < 0.001) than that of high-risk users with smartphone addiction. Smartphone users with a daily smartphone usage time from 2 h to 8 h a day were 1.096−1.347 times (p = 0.014 to p < 0.001) more likely to be satisfied with their sleep than smartphone users with a daily smartphone usage time over 8 h, who were unsatisfied with their sleep. The group that was not satisfied with their sleep had a significantly higher average daily smartphone usage time and total score on the smartphone addiction scale than the group that was satisfied with their sleep (both p < 0.001). In conclusion, it will be necessary to manage the use of smartphones to improve the sleep satisfaction of Korean adolescents.

Association of weekend catch-up sleep ratio and subjective sleep quality with depressive symptoms and suicidal ideation among Korean adolescents

Circadian misalignment caused by differences in sleep duration between weekends and weekdays may be associated with adolescent mental health and sleep quality may be able to compensate for this problem. This study aimed to investigate the association between weekend catch-up sleep (CUS) ratio and sleep quality with depressive symptoms and suicidal ideation among South Korean adolescents. We used data from the Korea Youth Risk Behavior Web-based Survey 2015–2019 involving 270,619 adolescents. The weekend CUS ratio was calculated by dividing the average weekend sleep duration by the average weekday sleep duration (< 1.00, 1.00 ≤ CUS < 1.50, or ≥ 1.50). Subjective sleep quality was categorized as poor, moderate, or good. Multiple logistic regression analyses were performed. A weekend CUS ratio of < 1.00 and poor sleep quality was significantly associated with mental health. Absolutely short sleep duration (CUS < 1.00 and weekday sleep duration < 5 h) was most associated with depressive symptoms and suicidal ideation. Furthermore, adolescents with a CUS ratio of ≥ 1.50 showed increased odds of depressive symptoms despite having good sleep quality. Appropriate weekend CUS may benefit adolescents’ mental health. When investigating the relationship between adolescents’ sleep and mental health, a weekend CUS ratio should be considered in addition to sleep quality and duration.

Trends in Obesity and Obesity-Related Risk Factors among Adolescents in Korea from 2009 to 2019

This study was conducted to identify the trends in obesity prevalence among adolescents and changes in the risk factors related to obesity. The study analyzed secondary data obtained from Korean Youth Risk Behavior Web-based Surveys conducted from 2009 to 2019. The Korean Youth Risk Behavior Web-based Survey is an annual survey of a nationwide representative sample of enrolled students aged 13–18 years in middle and high schools in Korea. Linear and trend analyses showed that the prevalence of obesity increased by 0.47% on average annually; this increase was statistically significant. Healthy food intake decreased significantly, but the prevalence of unhealthy food intake and the prevalence of skipping breakfast increased significantly. Vigorous-intensity physical activity, physical activity for over 60 min a day, and muscle-strengthening exercise for more than 3 days a week increased significantly, but so did the adolescents’ sedentary time. Therefore, health care providers and public policymakers need to actively manage adolescent obesity, which has been continuously increasing since 2009. In addition, long-term trends in obesity-related risk factors such as physical activity and dietary behaviors need to be considered in the development of obesity management strategies.

Association of Smartphone Use With Body Image Distortion and Weight Loss Behaviors in Korean Adolescents

IMPORTANCE

Despite high use of smartphones among adolescents, little is known about the association of smartphone use with body image and related behaviors.

OBJECTIVE

To examine the associations of duration of smartphone use and types of content most frequently accessed via smartphone with body image distortion and weight loss behaviors in adolescents.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study used data from the population-based Korea Youth Risk Behavior Web-Based Survey 2017. Participants comprised a nationally representative sample of 53 133 Korean adolescents aged 12 to 18 years. Data were collected from June 1 to July 18, 2017. The analysis was performed from February 7, 2020, to March 30, 2022.

EXPOSURES

Self-reported duration of smartphone use (min/d) and types of content (educational or informational searches; chatting, messaging, or email; social networking services or forums; games; videos, movies, or music; webtoons or web novels; and shopping or other activities) most frequently accessed during smartphone use.

MAIN OUTCOMES AND MEASURES

Body image distortion (overperception of body weight), weight loss attempt, use of inappropriate weight loss strategies (skipping meals, eating only 1 food at a time, vomiting, or using laxatives), and healthy weight loss behaviors (muscle-strengthening and aerobic physical activity). Multivariable logistic regression analysis was performed to estimate odds ratios (ORs) and 95% CIs, accounting for survey sampling and adjusting for potential confounders.

RESULTS

Among 53 133 participants, the mean (SD) age was 15.0 (1.8) years; 50.7% of participants were female, and 49.3% were male. After adjusting for types of content accessed, prolonged smartphone use (≥301 min/d) was positively associated with body image distortion (boys: OR, 1.17; 95% CI, 1.07-1.28; girls: OR, 1.20; 95% CI, 1.10-1.30) and inappropriate weight loss strategies (boys: OR, 1.54; 95% CI, 1.25-1.90; girls: OR, 2.45; 95% CI, 2.14-2.79) in both sexes compared with minimal smartphone use (1-120 min/d). After adjusting for duration of smartphone use, the use of smartphones mainly for videos, movies, or music (OR, 1.15; 95% CI, 1.02-1.29), webtoons or web novels (OR, 1.28; 95% CI, 1.10-1.48), and games (OR, 1.17; 95% CI, 1.03-1.32) was positively associated with body image distortion in boys compared with the use of smartphones mainly for educational or informational content. Among boys, the use of smartphones mainly for chatting, messaging, or email was positively associated with muscle-strengthening activity (OR, 1.31; 95% CI, 1.18-1.44) and aerobic physical activity (OR, 1.41; 95% CI, 1.29-1.55), as was the use of smartphones mainly for social networking services or forums (muscle-strengthening activity: OR, 1.27; 95% CI, 1.13-1.42; aerobic physical activity: OR, 1.28; 95% CI, 1.15-1.43). Among girls, the use of smartphones mainly for chatting, messaging, or email was positively associated with weight loss attempts (OR, 1.34; 95% CI, 1.19-1.51) and the use of inappropriate weight loss strategies (OR, 1.57; 95% CI, 1.25-1.99), as was the use of smartphones mainly for social networking services or forums (weight loss attempts: OR, 1.20; 95% CI, 1.07-1.36; use of inappropriate weight loss strategies: OR, 1.37; 95% CI, 1.08-1.73).

CONCLUSIONS AND RELEVANCE

In this cross-sectional study, both the duration of smartphone use and the types of content most frequently accessed via smartphone were associated with body image distortion and weight loss behaviors in adolescents. These findings suggest a need for the identification of strategies to help adolescents develop healthy smartphone use behaviors.

Korean college students’ attitudes toward a tobacco-free campus: a cross-sectional descriptive study

Purpose: A tobacco-free campus (TFC) is the most advanced tobacco-control policy for college campuses, but it has rarely been explored in Korea. This study aimed to explore Korean college students’ attitudes toward TFC and related factors.Methods: This cross-sectional descriptive study enrolled college students who were taking an elective course on smoking cessation and a healthy lifestyle at a university located in Incheon, Korea. Data were collected from March 1 to December 31, 2019 using a structured questionnaire, and study participants were recruited using convenience sampling.Results: Data on 309 college students were analyzed. Of those participants, 6.1% supported the TFC policy. Multiple logistic regression analysis showed that female gender (adjusted odds ratio [aOR]=5.80, 95% confidence interval [CI]=1.47-22.95), taking the course to quit smoking oneself (aOR=11.03, 95% CI=1.04-117.05), anxiety in the past month (aOR=4.27, 95% CI=1.06-17.31), and being a current smoker (aOR=0.06, 95% CI=0.01-0.70) were statistically significant independent predictors of TFC support.Conclusion: Women, students taking the course to quit smoking themselves, nonsmokers, and students who felt anxious in the past month were more likely to support TFC. Further research with more representative samples is required to examine the characteristics of people who favor TFC.

Trends in the association between body mass index and blood pressure among 19-year-old men in Korea from 2003 to 2017

The strength of association between the body mass index (BMI) and blood pressure (BP) varies with population and time. Therefore, identifying the trends in BMI-BP association in adolescents can help predict the upcoming metabolic and cardiovascular disease burden. For this reason, from physical examination data collected from 2003 to 2017, a total of 5,133,246 Korean men aged 19 years were assessed for the annual trends and changes in the BMI-BP association. During the 15-year period, the mean BMI increased from 22.5 to 23.5 kg/m², and the prevalence of obesity increased from 16.7 to 21.4%. Meanwhile, the mean systolic BP (SBP) decreased from 122.8 to 122.3 mmHg in the first year and gradually increased to 125.9 mmHg afterward. The diastolic BP (DBP) decreased from 71.5 to 70.0 mmHg in the first 4 years and then rose to 74.8 mmHg in the following years. The association analysis between BMI and SBP resulted in an annual increase in the correlation coefficient (SBP: 0.257-0.495, DBP: 0.164-0.413). The regression coefficient similarly increased between 2003 and 2015 but slightly decreased between 2015 and 2017 (SBP: 0.896-1.569, DBP: 0.405-0.861). The BMI-BP association increased over time (coefficient of the interaction term > 0, P < 0.001). Moreover, as the BMI increased, the annual increase in BP and BP per unit BMI also increased. In conclusion, this study emphasized a continuous shift towards obesity in BMI distribution and intensifying BMI-BP association over time in young men. Further research on factors affecting this BMI-BP association is needed to fully validate the potential applications of this hypothesis.

The Association between Physical Activity and Smartphone Addiction in Korean Adolescents: The 16th Korea Youth Risk Behavior Web-Based Survey, 2020

Many side effects of smartphone addiction have been reported, such as a lack of sleep, obesity, and poor concentration. However, the relationship between physical activity (PA) and smartphone addiction has not been fully elucidated. This study aimed to analyze the relationship between physical activity and smartphone addiction among 53,534 Korean adolescents using raw data from the 16th (2020) Korea Youth Risk Behavior Web-based Survey (KYRBS). The dependent variables were the general user group, potential risk user group, and high-risk user group for smartphone addiction. The independent variables were moderate PA (over 5 days per week), vigorous PA (over 3 days per week), and strength exercise (over 3 days per week). Sex, body mass index (BMI), school grade, academic achievement, sleep satisfaction, depression, loneliness, and stress were selected as confounding variables. A complex sample logistic regression analysis was performed. Potential smartphone addiction risk users showed statistically significant odds ratios of 1.423 (p < 0.001), 1.379 (p < 0.001), and 1.383 (p < 0.001) based on general users participating in moderate PA, vigorous PA, and strength exercise, respectively. High-risk users showed statistically significant odds ratios of 1.475 (p < 0.001), 1.484 (p < 0.001), and 1.619 (p < 0.001), respectively. In conclusion, to prevent smartphone addiction among Korean adolescents, participation in moderate PA for more than five days a week, vigorous PA for more than three days a week, or strength exercise for more than three days a week is considered effective.

Association Between Graphic Health Warning Labels on Cigarette Packs and Smoking Cessation Attempts in Korean Adolescent Smokers: A Cross-Sectional Study

Graphic health warning labels on cigarette packs inform smokers about the health risks associated with tobacco smoking. Adolescents are generally the main targets to influence by graphic health warning labels. This study investigated the association between graphic health warning labels on cigarette packs and attempts to quit smoking in South Korean adolescents. This cross-sectional study used data from the 2017 to 2019 Korea Youth Risk Behavior Web-based Survey, using multiple logistic regression for the analysis. The study population comprised 11,142 adolescents aged 12–18 years. The outcome variable was attempts to quit smoking among adolescent smokers who had seen graphic health warning labels. Attempts to quit smoking were higher among adolescent smokers who had seen graphic health warning labels compared to those who had not {boys, odds ratio (OR) = 1.72 [95% confidence interval (CI), 1.48–2.00]; girls, OR = 1.74 (95% CI, 1.33–2.28)}. The correlation was greater for adolescents who thought about the harm of smoking [boys, OR = 1.86 (95% CI, 1.60–2.16); girls, OR = 1.85 (95% CI, 1.41–2.43)] and the willingness to quit [boys, OR = 2.03 (95% CI, 1.74–2.36); girls, OR = 2.04 (95% CI, 1.55–2.68)] after seeing graphic health warning labels. Our findings indicate that graphic health warning labels on cigarette packs have the potential to lower smoking intentions of adolescents. We suggest that the use of graphic health warning labels is an effective policy-related intervention to reduce smoking in South Korean adolescents.