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Background: Osteoarthritis and rheumatoid arthritis (RA) are prevalent chronic joint disorders, with prevalence rates varying by sex. However, few studies have comprehensively documented the factors contributing to the sex-specific prevalence of osteoarthritis and RA, including sociological factors and the impact of the COVID-19 pandemic., Objective: This study aims to identify long-term trends in the sex-specific prevalence of osteoarthritis and RA from 2005 to 2021 while examining the factors that serve as vulnerabilities specific to each sex within the context of the COVID-19 pandemic., Methods: Data were collected from a nationally representative sample of 110,225 individuals through the Korea National Health and Nutrition Examination Survey from 2005 to 2021. The study included patients aged 19 years and older diagnosed with osteoarthritis or RA in South Korea. Data were analyzed using weighted trends to accurately represent the sample population, with a 95% CI. Weighted logistic and regression models were used to identify vulnerable groups at risk of osteoarthritis or RA during the pandemic to assess sex-specific trends., Results: In total, 110,225 individuals (n=48,410, 43.92% male participants) were analyzed from 2005 to 2021, with prevalence rates remaining stable over time and higher in female than in male participants. Notably, during the pandemic, female participants aged 60 years and older exhibited a prevalence of osteoarthritis that was 4.92 times greater than male participants and a prevalence of RA that was 6.44 times greater (osteoarthritis: prevalence ratio [PR] 69.78, 95% CI 41.66-116.88; RA: PR 17.27, 95% CI 8.75-34.07). In terms of osteoarthritis, male participants did not show a significant association with BMI (PR 1.40, 95% CI 1.21-1.61; P=.47), whereas female participants exhibited a significantly higher vulnerability within the obese group (PR 1.68, 95% CI 1.55-1.83; P<.001). Regarding RA, lower education levels were associated with increased vulnerability, with male participants showing a greater risk than female participants (male participants: PR 2.29, 95% CI 1.61-3.27 and female participants: PR 1.50, 95% CI 1.23-1.84)., Conclusions: This study reveals that women in South Korea have a higher prevalence of osteoarthritis and RA than men. Understanding these sex-specific trends and identifying vulnerability factors can enhance preventive efforts and patient care., (©Seoyoung Park, Yejun Son, Hyeri Lee, Hayeon Lee, Jinseok Lee, Jiseung Kang, Lee Smith, Masoud Rahmati, Elena Dragioti, Mark A Tully, Guillaume Fond, Laurent Boyer, Jun Hyuk Lee, Damiano Pizzol, Jaeyu Park, Selin Woo, Dong Keon Yon. Originally published in JMIR Public Health and Surveillance (https://publichealth.jmir.org), 01.11.2024.)

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., (© 2024. The Author(s).)

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., (©Jinyoung Jeong, Seungjun Lee, Kyeongmin Lee, Seokjun Kim, Jaeyu Park, Yejun Son, Hyeri Lee, Hayeon Lee, Jiseung Kang, Masoud Rahmati, Damiano Pizzol, Lee Smith, Guillermo F López Sánchez, Elena Dragioti, Guillaume Fond, Laurent Boyer, Selin Woo, Sang Youl Rhee, Dong Keon Yon. Originally published in JMIR Public Health and Surveillance (https://publichealth.jmir.org), 09.10.2024.)

Background/aims: Considering emerging evidence on long COVID, comprehensive analyses of the post-acute complications of SARS-CoV-2 infection in the gastrointestinal and hepatobiliary systems are needed. We aimed to investigate the impact of COVID-19 on the long-term risk of gastrointestinal and hepatobiliary diseases and other digestive abnormalities., Methods: We used three large-scale population-based cohorts: the Korean cohort (discovery cohort), the Japanese cohort (validation cohort-A), and the UK Biobank (validation cohort-B). A total of 10,027,506 Korean, 12,218,680 Japanese, and 468,617 UK patients aged ≥20 years who had SARS-CoV-2 infection between 2020 and 2021 were matched to non-infected controls. Seventeen gastrointestinal and eight hepatobiliary outcomes as well as nine other digestive abnormalities following SARS-CoV-2 infection were identified and compared with controls., Results: The discovery cohort revealed heightened risks of gastrointestinal diseases (HR 1.15; 95% CI 1.08-1.22), hepatobiliary diseases (HR 1.30; 95% CI 1.09-1.55), and other digestive abnormalities (HR 1.05; 95% CI 1.01-1.10) beyond the first 30 days of infection, after exposure-driven propensity score-matching. The risk was pronounced according to the COVID-19 severity. The SARS-CoV-2 vaccination was found to lower the risk of gastrointestinal diseases but did not affect hepatobiliary diseases and other digestive disorders. The results derived from validation cohorts were consistent. The risk profile was most pronounced during the initial 3 months; however, it persisted for >6 months in validation cohorts, but not in the discovery cohort., Conclusion: The incidence of gastrointestinal disease, hepatobiliary disease, and other digestive abnormalities increased in patients with SARS-CoV-2 infection during the post-acute phase.

School counsellors in South Korea face significant emotional exhaustion due to their challenging occupational environment. Previous studies have shown that cognitive reappraisal (CR) reduces emotional exhaustion, whereas expressive suppression (ES) increases it. However, these findings predominantly rely on trait questionnaires within cross-sectional approaches, overlooking the dynamic nature of emotion regulation (ER) strategy selection. Individuals may choose strategies that deviate from their general tendencies based on situational demands. There is limited empirical knowledge regarding the interaction between trait and state regulation strategies and their influence on exhaustion. Utilizing the strategy-situation fit hypothesis, this study examines the context-specific effects of ER strategies, considering both situational contexts and individual response tendencies. A multilevel analysis was performed to examine the influence of state and trait ER strategies on daily emotional exhaustion. A daily diary study was conducted for 5 days with 111 Korean school counsellors. Daily CR was associated with lower daily exhaustion and daily ES predicted higher daily exhaustion. Contrastingly, none of the trait ER strategies had an impact on daily exhaustion, but the trait level of both strategies significantly moderated the relationship between daily CR and exhaustion. The positive impact of daily CR was more pronounced in school counsellors who often utilized suppression strategies, and this impact was also evident in trait reappraisal. Re-evaluating daily emotions instead of suppressing them may assist in coping with emotional exhaustion caused by work. The effectiveness of these strategies may vary based on an individual's inclination to regulate emotions as state and trait. ER may aid in implementing preventive interventions for school counsellors experiencing emotional exhaustion., (© 2024 The Author(s). Stress and Health published by John Wiley & Sons Ltd.)

Background: Although previous studies have investigated trends in unmet health care and dental care needs, most have focused on specific groups, such as patients with chronic conditions and older adults, and have been limited by smaller data sets., Objective: This study aims to investigate the trends and relative risk factors for unmet health care and dental care needs, as well as the impact of the COVID-19 pandemic on these needs., Methods: We assessed unmet health care and dental care needs from 2009 to 2022 using data from the Korea Community Health Survey (KCHS). Our analysis included responses from 2,750,212 individuals. Unmet health care or dental care needs were defined as instances of not receiving medical or dental services deemed necessary by experts or desired by patients., Results: From 2009 to 2022, the study included 2,700,705 individuals (1,229,671 men, 45.53%; 673,780, 24.95%, aged 19-39 years). Unmet health care needs decreased before the COVID-19 pandemic; however, during the pandemic, there was a noticeable increase (β diff 0.10, 95% CI 0.09-0.11). Unmet dental care needs declined before the pandemic and continued to decrease during the pandemic (β diff 0.23, 95% CI 0.22-0.24). Overall, the prevalence of unmet dental care needs was significantly higher than that for unmet health care needs. While the prevalence of unmet health care needs generally decreased over time, the β difference during the pandemic increased compared with prepandemic values., Conclusions: Our study is the first to analyze national unmet health care and dental care needs in South Korea using nationally representative, long-term, and large-scale data from the KCHS. We found that while unmet health care needs decreased during COVID-19, the decline was slower compared with previous periods. This suggests a need for more targeted interventions to prevent unmet health care and dental care needs., (©Yeji Kim, Soeun Kim, Somin Lee, Jaeyu Park, Ai Koyanagi, Lee Smith, Min Seo Kim, Guillaume Fond, Laurent Boyer, Guillermo Felipe López Sánchez, Elena Dragioti, Hyeon Jin Kim, Hayeon Lee, Yejun Son, Minji Kim, Sunyoung Kim, Dong Keon Yon. Originally published in JMIR Public Health and Surveillance (https://publichealth.jmir.org), 18.09.2024.)

Background: Type 2 diabetes poses an increasing disease burden in South Korea. The development and management of type 2 diabetes are closely related to lifestyle and socioeconomic factors, which have undergone substantial changes over the past few decades, including during the COVID-19 pandemic., Objective: This study aimed to investigate long-term trends in type 2 diabetes prevalence, awareness, treatment, and control. It also aimed to determine whether there were substantial alterations in the trends during the pandemic and whether these changes were more pronounced within specific demographic groups., Methods: This study examined the prevalence, awareness, treatment, and control of type 2 diabetes in a representative sample of 139,786 South Koreans aged >30 years, using data from the National Health and Nutrition Examination Survey and covering the period from 1998 to 2022. Weighted linear regression and binary logistic regression were performed to calculate weighted β coefficients or odds ratios. Stratified analyses were performed based on sex, age, region of residence, obesity status, educational background, household income, and smoking status. β (difference) was calculated to analyze the trend difference between the prepandemic period and the COVID-19 pandemic. To identify groups more susceptible to type 2 diabetes, we estimated interaction terms for each factor and calculated weighted odds ratios., Results: From 1998 to 2022, a consistent increase in the prevalence of type 2 diabetes was observed among South Koreans, with a notable rise to 15.61% (95% CI 14.83-16.38) during the pandemic. Awareness followed a U-shaped curve, bottoming out at 64.37% (95% CI 61.79-66.96) from 2013 to 2015 before increasing to 72.56% (95% CI 70.39-74.72) during the pandemic. Treatment also increased over time, peaking at 68.33% (95% CI 65.95-70.71) during the pandemic. Control among participants with diabetes showed no substantial change, maintaining a rate of 29.14% (95% CI 26.82-31.47) from 2020 to 2022, while control among treated participants improved to 30.68% (95% CI 27.88-33.48). During the pandemic, there was a steepening of the curves for awareness and treatment. However, while the slope of control among participants being treated increased, the slope of control among participants with diabetes showed no substantial change during the pandemic. Older populations and individuals with lower educational level exhibited less improvement in awareness and control trends than younger populations and more educated individuals. People with lower income experienced a deceleration in prevalence during the pandemic., Conclusions: Over the recent decade, there has been an increase in type 2 diabetes prevalence, awareness, treatment, and control. During the pandemic, a steeper increase in awareness, treatment, and control among participants being treated was observed. However, there were heterogeneous changes across different population groups, underscoring the need for targeted interventions to address disparities and improve diabetes management for susceptible populations., (©Wonwoo Jang, Seokjun Kim, Yejun Son, Soeun Kim, Hyeon Jin Kim, Hyesu Jo, Jaeyu Park, Kyeongmin Lee, Hayeon Lee, Mark A Tully, Masoud Rahmati, Lee Smith, Jiseung Kang, Selin Woo, Sunyoung Kim, Jiyoung Hwang, Sang Youl Rhee, Dong Keon Yon. Originally published in JMIR Public Health and Surveillance (https://publichealth.jmir.org), 27.08.2024.)

We investigated whether SARS-CoV-2 infection is associated with short- and long-term neuropsychiatric sequelae. We used population-based cohorts from the Korean nationwide cohort (discovery; n = 10,027,506) and the Japanese claims-based cohort (validation; n = 12,218,680) to estimate the short-term (<30 days) and long-term (≥30 days) risks of neuropsychiatric outcomes after SARS-CoV-2 infection compared with general population groups or external comparators (people with another respiratory infection). Using exposure-driven propensity score matching, we found that both the short- and long-term risks of developing neuropsychiatric sequelae were elevated in the discovery cohort compared with the general population and those with another respiratory infection. A range of conditions including Guillain-Barré syndrome, cognitive deficit, insomnia, anxiety disorder, encephalitis, ischaemic stroke and mood disorder exhibited a pronounced increase in long-term risk. Factors such as mild severity of COVID-19, increased vaccination against COVID-19 and heterologous vaccination were associated with reduced long-term risk of adverse neuropsychiatric outcomes. The time attenuation effect was the strongest during the first six months after SARS-CoV-2 infection, and this risk remained statistically significant for up to one year in Korea but beyond one year in Japan. The associations observed were replicated in the validation cohort. Our findings contribute to the growing evidence base on long COVID by considering ethnic diversity., (© 2024. The Author(s), under exclusive licence to Springer Nature Limited.)

Background: Understanding the association between hypertension prevalence and socioeconomic and behavioral variables during a pandemic is essential, and this analysis should extend beyond short-term trends., Objective: This study aims to examine long-term trends in the prevalence of participants diagnosed with and receiving treatment for hypertension, using data collected by a nationally representative survey from 2009 to 2022, which includes the COVID-19 pandemic era., Methods: A nationwide, population-based, cross-sectional study used data collected from the South Korea Community Health Survey between 2009 and 2022. The study sample comprised 3,208,710 Korean adults over a period of 14 years. We aimed to assess trends in the prevalence of participants diagnosed with and receiving treatment for hypertension in the national population from 2009 to 2022, with a specific focus on the COVID-19 pandemic, using weighted linear regression models., Results: Among the included 3,072,546 Korean adults, 794,239 (25.85%) were aged 19-39 years, 1,179,388 (38.38%) were aged 40-59 years; 948,097 (30.86%) were aged 60-79 years, and 150,822 (4.91%) were aged 80 years or older. A total of 1,426,379 (46.42%) were men; 761,896 (24.80%) and 712,264 (23.18%) were diagnosed with and received treatment for hypertension, respectively. Although the overall prevalence over the 14-year period increased, the upward trends of patients diagnosed with and receiving treatment for hypertension decreased during the COVID-19 pandemic era compared with the prepandemic era (β difference for trend during vs before the pandemic -.101, 95% CI -0.107 to -0.094 vs -.133, 95% CI -0.140 to -0.127). Notably, the trends in prevalence during the pandemic were less pronounced in subgroups of older adults (≥60 years old) and individuals with higher alcohol consumption (≥5 days/month)., Conclusions: This nationwide representative study found that the national prevalence of participants diagnosed with and receiving treatment for hypertension increased during the prepandemic era. However, there was a marked decrease in these trends during the prepandemic era, compared with the pandemic era, particularly among specific subgroups at increased risk of negative outcomes. Future studies are needed to evaluate the factors associated with changes in the prevalence of hypertension during the COVID-19 pandemic., (©Hyeri Lee, Minji Kim, Selin Woo, Jaeyu Park, Hyeon Jin Kim, Rosie Kwon, Ai Koyanagi, Lee Smith, Min Seo Kim, Guillermo F López Sánchez, Elena Dragioti, Jinseok Lee, Hayeon Lee, Masoud Rahmati, Sang Youl Rhee, Jun Hyuk Lee, Ho Geol Woo, Dong Keon Yon. Originally published in JMIR Public Health and Surveillance (https://publichealth.jmir.org), 30.07.2024.)

Previous research has not investigated the persistent cutaneous immune-related adverse events (cirAEs) related to long COVID to investigate the long-term sequelae. This multinational study, using a propensity-matched overlap weighting method, utilizes large national claims-based cohorts, using ICD-10 code diagnosis, focusing on patients aged ≥20 years from three countries: South Korean, Japanese, and the British cohorts. To estimate the risk of cirAEs in long COVID, the persistence or emergence of cirAEs occurring 4 weeks after the initial SARS-CoV-2 infection, we employed a Cox proportional hazard regression model. The Korean cohort (n = 5,937,373; mean age 49.2 years [SD: 13.2]), the Japanese cohort (n = 4,307,587; 42.5 years [13.6]), and the UK cohort (n = 395,435; 71.0 years [8.07]) were presented. An increased risk of cirAEs in long COVID was observed (HR, 1.10; 95% CI, 1.06-1.14) in Korean cohort, while a similar association was observed in Japanese and UK cohorts. The long-term risk of cirAEs in long COVID was higher in more severe COVID-19 cases (1.31; 1.22-1.39). Unlike the increased risk of cirAEs in long COVID, COVID-19 vaccination attenuated the risk, especially with two or more doses (1.03; 0.95-1.11) or heterologous regimens (0.98; 0.76-1.27). The time attenuation effect indicated a sustained risk for up to 6 months postinfection (<3 months: 1.13 [1.07-1.19]; 3-6 months: 1.14 [1.06-1.22]). SARS-CoV-2 infection is associated with an increased risk of cirAEs in the aspect of long COVID. Vaccination might reduce this risk, highlighting the need for preventive strategies in long COVID management., (© 2024 Wiley Periodicals LLC.)

Considering the significant burden of post-acute COVID-19 conditions among patients infected with SARS-CoV-2, we aimed to identify the risk of acute respiratory complications or post-acute respiratory sequelae. A binational population-based cohort study was conducted to analyze the risk of acute respiratory complications or post-acute respiratory sequelae after SARS-CoV-2 infection. We used a Korean nationwide claim-based cohort (K-COV-N; n = 2,312,748; main cohort) and a Japanese claim-based cohort (JMDC; n = 3,115,606; replication cohort) after multi-to-one propensity score matching. Among 2,312,748 Korean participants (mean age, 47.2 years [SD, 15.6]; 1,109,708 [48.0%] female), 17.1% (394,598/2,312,748) were infected with SARS-CoV-2. The risk of acute respiratory complications or post-acute respiratory sequelae is significantly increased in people with SARS-CoV-2 infection compared to the general population (acute respiratory complications: HR, 8.06 [95% CI, 6.92-9.38]; post-acute respiratory sequelae: 1.68 [1.62-1.75]), and the risk increased with increasing COVID-19 severity. We identified COVID-19 vaccination as an attenuating factor, showing a protective association against acute or post-acute respiratory conditions. Furthermore, while the excess post-acute risk diminished with time following SARS-CoV-2 infection, it persisted beyond 6 months post-infection. The replication cohort showed a similar pattern in the association. Our study comprehensively evaluates respiratory complications in post-COVID-19 conditions, considering attenuating factors such as vaccination status, post-infection duration, COVID-19 severity, and specific respiratory conditions., (© 2024. The Author(s).)

This study aimed to present a new approach to predict to delirium admitted to the acute palliative care unit. To achieve this, this study employed machine learning model to predict delirium in patients in palliative care and identified the significant features that influenced the model. A multicenter, patient-based registry cohort study in South Korea between January 1, 2019, and December 31, 2020. Delirium was identified by reviewing the medical records based on the criteria of the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition. The study dataset included 165 patients with delirium among 2314 patients with advanced cancer admitted to the acute palliative care unit. Seven machine learning models, including extreme gradient boosting, adaptive boosting, gradient boosting, light gradient boosting, logistic regression, support vector machine, and random forest, were evaluated to predict delirium in patients with advanced cancer admitted to the acute palliative care unit. An ensemble approach was adopted to determine the optimal model. For k-fold cross-validation, the combination of extreme gradient boosting and random forest provided the best performance, achieving the following accuracy metrics: 68.83% sensitivity, 70.85% specificity, 69.84% balanced accuracy, and 74.55% area under the receiver operating characteristic curve. The performance of the isolated testing dataset was also validated, and the machine learning model was successfully deployed on a public website ( http://ai-wm.khu.ac.kr/Delirium/ ) to provide public access to delirium prediction results in patients with advanced cancer. Furthermore, using feature importance analysis, sex was determined to be the top contributor in predicting delirium, followed by a history of delirium, chemotherapy, smoking status, alcohol consumption, and living with family. Based on a large-scale, multicenter, patient-based registry cohort, a machine learning prediction model for delirium in patients with advanced cancer was developed in South Korea. We believe that this model will assist healthcare providers in treating patients with delirium and advanced cancer., (© 2024. The Author(s).)

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., (©Hyejun Kim, Yejun Son, Hojae Lee, Jiseung Kang, Ahmed Hammoodi, Yujin Choi, Hyeon Jin Kim, Hayeon Lee, Guillaume Fond, Laurent Boyer, Rosie Kwon, Selin Woo, Dong Keon Yon. Originally published in the Journal of Medical Internet Research (https://www.jmir.org), 17.05.2024.)

Previous studies have proposed alopecia areata (AA) as a potential outcome of COVID-19 infection among autoimmune diseases, yet the findings might be inconclusive and difficult to generalize due to limited sample sizes and evidence levels. Thus, we aimed to investigate in detail the long-term risk of AA following SARS-CoV-2 infection based on large, binational, general population-based cohort studies. Our study investigated the long-term AA risk after SARS-CoV-2 infection by analyzing bi-national, claim-based cohorts in South Korea and Japan: a Korean nationwide cohort (K-COV-N cohort; discovery cohort; total n = 10 027 506) and a Japanese claims-based cohort (JMDC cohort; validation cohort; total n = 12 218 680). AA was identified based on the international classification of diseases 10th revision code (L63) requiring at least three claims within 1 year. After exposure-driven propensity score matching, SARS-CoV-2 infection was associated with an increased risk of incident AA (aHR, 1.66; 95% CI, 1.38-1.99). This increased risk was observed and persisted for up to 6 months. A similar pattern was observed in the validation cohort. As modifiable factors, severe COVID-19 increased the risk of AA, whereas receiving two or more doses of the COVID-19 vaccine before infection decreased the risk of AA. Through a bi-national cohort study in South Korea and Japan, SARS-CoV-2 infection was associated with an elevated risk for incident AA in the aspect of long COVID., (© 2024 Wiley Periodicals LLC.)

Importance: Despite the COVID-19 pandemic's effect on daily life, limited research exists on the prevalence and risk factors of suicidality and sadness among South Korean adolescents., Objectives: To examine whether the observed sadness and suicidality in the early to middle periods of the COVID-19 pandemic differed from the expected level and to investigate changes in risk factors for sadness and suicidality., Design, Setting, and Participants: This nationwide serial cross-sectional survey study used data on 1 109 776 Korean adolescents aged 13 to 18 years from the Korea Youth Risk Behavior Web-based Survey from 2005 to 2021., Exposure: The COVID-19 pandemic., Main Outcomes and Measures: The pattern of changes in the percentage or proportion of sadness or suicidality, as well as the risk factors for sadness or suicidality. The transitional effect of the COVID-19 pandemic was assessed using weighted odds ratios (wORs) or weighted beta coefficients with 95% CIs., Results: Between 2005 and 2021, 1 109 776 adolescents (mean [SD] age, 15.0 [1.7] years; 51.5% male adolescents; and 51.7% in grades 7-9 and 48.3% in grades 10-12) were included in the Korea Youth Risk Behavior Web-based Survey. The slope of the long-term trends in sadness and suicidality decreased in the prepandemic period (sadness: from 37.8% [95% CI, 37.4%-38.2%] in 2005-2007 to 26.1% [95% CI, 25.9%-26.4%] in 2016-2019; suicidality: from 23.0% [95% CI, 22.7%-23.3%] in 2005-2007 to 12.3% [95% CI, 12.1%-12.5%] in 2016-2019), whereas the slope increased during the COVID-19 pandemic (sadness: from 25.0% [95% CI, 24.5%-25.6%] in 2020 to 26.6% [95% CI, 26.1%-27.1%] in 2021; trend difference in β, 0.249 [95% CI, 0.236-0.262]; suicidality: from 10.7% [95% CI, 10.3%-11.1%] in 2020 to 12.5% [95% CI, 12.1%-12.9%] in 2021; trend difference in β, 0.328 [95% CI, 0.312-0.344]). The trends presented a similar tendency in the subgroups according to sex, school grade, residential area, smoking status, and current alcohol use. Compared with the prepandemic period, the risk factors associated with sadness during the pandemic were younger age (wOR, 0.907; 95% CI, 0.881-0.933), female sex (wOR, 1.031; 95% CI, 1.001-1.062), urban residence (wOR, 1.120; 95% CI, 1.087-1.153), current smoking status (wOR, 1.134; 95% CI, 1.059-1.216), and current alcohol use (wOR, 1.051; 95% CI, 1.002-1.102). Female sex (wOR, 1.064; 95% CI, 1.021-1.109), urban residence (wOR, 1.117; 95% CI, 1.074-1.162), and low economic status (wOR, 1.286; 95% CI, 1.180-1.403) were the risk factors significantly associated with suicidality after the COVID-19 pandemic began., Conclusions and Relevance: In this nationwide serial cross-sectional survey study of South Korean adolescents, the slope of the prevalence of sadness and suicidality increased during the COVID-19 pandemic after a decrease prior to the pandemic. The findings suggest that public health measures are needed to recognize vulnerable groups with risk factors and to prevent an increase in sadness and suicidality among adolescents during the COVID-19 pandemic.