Long-Term Autoimmune Inflammatory Rheumatic Outcomes of COVID-19 : A Binational Cohort Study.

BACKGROUND: Some data suggest a higher incidence of diagnosis of autoimmune inflammatory rheumatic diseases (AIRDs) among patients with a history of COVID-19 compared with uninfected patients. However, these studies had methodological shortcomings. OBJECTIVE: To investigate the effect of COVID-19 on long-term risk for incident AIRD over various follow-up periods. DESIGN: Binational, longitudinal, propensity-matched cohort study. SETTING: Nationwide claims-based databases in South Korea (K-COV-N cohort) and Japan (JMDC cohort). PARTICIPANTS: 10 027 506 Korean and 12 218 680 Japanese patients aged 20 years or older, including those with COVID-19 between 1 January 2020 and 31 December 2021, matched to patients with influenza infection and to uninfected control patients. MEASUREMENTS: The primary outcome was onset of AIRD (per appropriate codes from the International Classification of Diseases, 10th Revision) 1, 6, and 12 months after COVID-19 or influenza infection or the respective matched index date of uninfected control patients. RESULTS: Between 2020 and 2021, among the 10 027 506 Korean participants (mean age, 48.4 years [SD, 13.4]; 50.1% men), 394 274 (3.9%) and 98 596 (0.98%) had a history of COVID-19 or influenza, respectively. After propensity score matching, beyond the first 30 days after infection, patients with COVID-19 were at increased risk for incident AIRD compared with uninfected patients (adjusted hazard ratio, 1.25 [95% CI, 1.18 to 1.31]) and influenza-infected control patients (adjusted hazard ratio, 1.30 [CI, 1.02 to 1.59]). The risk for incident AIRD was higher with more severe acute COVID-19. Similar patterns were observed in the Japanese cohort. LIMITATIONS: Referral bias due to the pandemic; residual confounding. CONCLUSION: SARS-CoV-2 infection was associated with increased risk for incident AIRD compared with matched patients without SARS-CoV-2 infection or with influenza infection. The risk for incident AIRD was higher with greater severity of acute COVID-19. PRIMARY FUNDING SOURCE: National Research Foundation of Korea.

Prenatal and postnatal exposure to antibiotics and risk of food allergy in the offspring: A nationwide birth cohort study in South Korea.

BACKGROUND: There are only preliminary studies examining the associations of postnatal antibiotic exposure with food allergy in childhood, and the effect of antibiotic exposure in utero has not been resolved. Thus, we aimed to investigate the effect of prenatal and postnatal antibiotic exposure on the risk of food allergy in childhood. METHODS: Using the nationwide birth cohort in South Korea, all 3,163,206 infants (pairing mother; n = 2,322,735) born in South Korea between 2010 and 2017 were included in the analysis. The primary outcome was the diagnosis of food allergy, and the observation period was between January 1, 2009, and December 31, 2020. We implemented four different designs for the study, which consisted of a full unmatched cohort, 1:1 propensity-matched cohort, sibling comparison cohort, and health screening cohort along with multiple subgroup analyses. RESULTS: During the follow-up period (median 6.92 years [IQR, 4.72-9.00]) of the 3,161,858 infants (52.6% male) in the birth cohort, 29,973 (1.9%) were diagnosed with food allergies. After a 1:1 propensity score matching, the use of antibiotics increased the risk of overall food allergy (prenatal [HR, 1.05; 95% CI, 1.04-1.09] and postnatal [HR, 1.05; 95% CI, 1.01-1.10] periods). The association was more significantly accentuated when antibiotic exposure was used in the short term, and the children were born preterm or with low birthweight; however, a trimester-specific effect was not observed. We observed more pronounced risks of food allergy in the health screening cohort (prenatal, 17%; postnatal, 15%), thus addressing the adverse effects of critical factors including maternal BMI, smoking status, and type of infant feeding. Similar trends were observed across all four differnt cohorts. CONCLUSION: This study reported a moderate association between early-life antibiotic use and subsequent food allergy during childhood throughout four different designs of analyses. This study suggests that clinicians need to consider the risks and benefits of antibiotics when administering antibiotics to individuals in the prenatal and postnatal periods.

Comparison of clinical manifestations in mpox patients living with HIV versus without HIV: A systematic review and meta-analysis.

Currently, many cases of mpox patients living with the human immunodeficiency virus (HIV) have been reported. Immunocompromised mpox patients, including those living with HIV are noted for an increased risk for severe symptoms; however, existing studies did not focus on the statistical comparison of mpox outcomes associated with HIV. Thus, we conducted a systematic review and meta-analysis to evaluate and compare the clinical manifestations of mpox in people living with HIV (PLWH) and people without HIV. In this systematic review and meta-analysis, PubMed/MEDLINE, Embase, and Google Scholar were searched up to March 7, 2023. A random effects model was used to calculate the pooled prevalence along with the 95% confidence intervals (CI), and the odds ratio and its corresponding 95% CIs were calculated to elucidate the significance of each clinical feature for mpox patients with and without HIV. In this study, we included 99 published papers with 2413 patients with mpox (median age, 35.5 years; PLWH n = 1151) from 27 countries across six continents. The odds ratio of the mpox outcomes with PLWH in comparison to patients without HIV was found to be significant for skin rash (1.24, 95% CI: 1.01-1.53), proctitis (2.03, 95% CI: 1.36-3.04), cough (0.57, 95% CI: 0.33-0.98), and diarrhea (3.85, 95% CI: 1.24-11.98). The odds ratio of mpox patients with HIV for historical infections of syphilis was 2.14 (95% CI: 1.38-3.32), compared with those without HIV. This is the first international and comprehensive study that performed a systematic review and meta-analysis to statistically measure mpox manifestations according to HIV status. As clinical features related to mucosal contact were characteristically pronounced in PLWH, our systematic review provides insight that the primary invasion site of infection strongly relates to the outcomes of mpox.

National trends in physical activity among adolescents in South Korea before and during the COVID-19 pandemic, 2009-2021.

With the ongoing COVID-19 pandemic, several previous studies from different countries showed that physical activity (PA) decreased during the COVID-19 outbreak. However, few studies have examined the recent tendency of PA in the adolescent population. Thus, we aimed to investigate the long-term trend of PA in Korean youth and the prevalence changes between before and during the COVID-19 pandemic. Data from Korea Youth Risk Behavior Web-Based Survey (KYRBS) was collected for consecutive years between 2009 and 2021. The period was separated into prepandemic (2009-2019), early-pandemic (2020), and mid-pandemic (2021). Self-reported amount of PA was categorized into four groups (insufficient, aerobic, muscle strengthening, and both physical activities) according to World Health Organization (WHO) PA guidelines. A total of 840 488 adolescents aged 12-18 who fully responded to the survey were selected (response rate: 95.2%). The 13-year trends in the proportion of adolescents who reported aerobic and muscle-strengthening activities met or exceeded 2020 WHO exercise guidelines for adolescents plateaued (11.9% from 2009 to 2011, 14.2% from 2018 to 2019, 14.4% from 2020, and 14.0% from 2021); however, the slope decreased during the pandemic (ßdiff , -0.076; 95% confidence interval [CI], -0.123 to -0.029). Proportion of sufficient aerobic exercise among adolescents sharply decreased midst the pandemic (28.0% from 2009 to 2011, 29.4% from 2018 to 2019, and 23.8% from 2020; ßdiff , -0.266; 95% CI, -0.306 to -0.226) but increased again in 2021 (26.0% from mid-COVID 19; 95% CI, 25.4-26.7). Similar patterns were observed in Metabolic Equivalent Task (MET) score (MET-min/week; 804.1 from 2018 to 2019, 720.9 from 2020, and 779.6 from 2021). The mean difference in MET score between pre-COVID and post-COVID was -55.4 MET-min/week (95% CI, -70.5 to -40.3). Through a nationwide representative study, there was no significant difference with regard to the number of Korean adolescents who achieved the PA guidelines (pre and postpandemic); however, the prevalence of recommended levels of PA needs to increase more based on the trend before the COVID-19 outbreak. The findings of this study suggest reinforcement of the importance of public health policies for Korean youths to be more physically active, especially during and after the pandemic.

Investigation of changes in the physical activity and fall experience before and after the COVID-19 pandemic.

This study aimed to investigate the changes in physical activity levels and the rate of falls during the COVID-19 pandemic in the Korean population. The Korean Community Health Survey (KCHS) conducted in 2019 was compared with that conducted in 2020. Simple or multiple linear regression with complex sampling was conducted to calculate the estimated value (EV) of physical activity in the 2020 group vs. the 2019 group. The odds ratio (OR) of fall histories was calculated using simple or multiple logistic regression with complex sampling for the 2020 group compared to the 2019 group. The time spent on vigorous and moderate physical activity was lower in the 2020 group than in the 2019 group (EV = -10.0, 95% CI = -12.1 to -8.0, P < 0.001 for vigorous exercise and EV = -24.0, 95% CI = -26.7 to -21.4, P < 0.001 for moderate exercise). The rate of falls was lower in the 2020 group than in the 2019 group (OR = 0.66, 95% CI = 0.62 to 0.70, P < 0.001). Vigorous and moderate exercise decreased after the COVID-19 pandemic compared to before the pandemic. The occurrence of falls was lower during the COVID-19 pandemic than in the pre-pandemic period.

Association between Proton Pump Inhibitors and Hearing Impairment: A Nested Case-Control Study.

This study investigated the association of previous use of proton pump inhibitors (PPIs) with the rate of hearing impairment. The ≥40-year-old population in the Korean National Health Insurance Service-Health Screening Cohort was enrolled. The 6626 registered hearing-impaired patients were matched with 508,240 control participants for age, sex, income, region of residence, and index date (date of hearing impairment diagnosis). The prescription histories of PPIs were collected for 2 years before the index date. The odds ratios of the duration of PPI use for hearing impairment were analyzed using conditional logistic regression. Subgroups of age/sex and severity of hearing impairments were additionally analyzed for the relation of PPI use with hearing impairment. PPI use for 30-365 days was associated with a 1.65-times higher odds of hearing impairment (95% confidence interval (CI) = 1.47-1.86 for 30-365 days of PPI medication). PPI use for ≥365 days was also related to 1.52-times higher odds of hearing impairment (95% CI = 1.35-1.72, p < 0.001). All age and sex subgroups demonstrated a positive association between PPI use and hearing impairment. Severe hearing impairment showed consistently higher odds of a relation with PPI use. PPI use was associated with an increased rate of hearing impairment.

Association between asthma and cardiovascular disease.

BACKGROUND: Epidemiological studies on the association between asthma and cardiovascular disease have reported conflicting results. This cross-sectional study evaluated the association between asthma and ischaemic heart disease (IHD)/stroke in Korean adults. MATERIALS AND METHODS: Data from the Korean Genome and Epidemiology Study-Health Examinees were used. Among 173 209 participants, 3162 asthmatic and 159 408 control participants were selected. Histories of asthma, IHD and stroke were obtained. Participants were categorized according to their current status of asthma management: 'well-controlled', 'being treated', and 'not being treated'. Crude and adjusted (age, gender, body mass index, income, smoking, alcohol consumption, hypertension, diabetes, dyslipidaemia and nutritional intake) odds ratios (ORs) for IHD and stroke in asthmatic patients were analysed using a multiple logistic regression model. RESULTS: Participants with asthma reported a significantly higher prevalence of IHD (6.0% vs 3.0%) and stroke (2.3% vs 1.4%) than those without asthma (P < .001). Asthmatic participants had a higher OR (1.46, 95% confidence interval [CI] = 1.251-1.71, P < .001) for IHD than those without asthma. The association between asthma and IHD was significant only in patients aged ≥53 years (men: adjusted OR = 1.31, 95% CI = 1.01-1.70, P = .046; women: adjusted OR = 1.64, 95% CI = 1.32-2.03, P < .001) according to age and sex and in the 'not being treated' asthma group (adjusted OR = 1.47, 95% CI = 1.14-1.91, P = .003) according to the asthma management status. Stroke was not significantly associated with asthma (adjusted OR = 1.17, 95% CI = 0.92-1.48, P = .203) in the adjusted model and all subgroup analyses. CONCLUSION: Asthma was associated with IHD, mainly in older patients and untreated asthma patients, but not with stroke.

Increased risk of herpes zoster in patients with psoriasis: A longitudinal follow-up study using a national sample cohort.

BACKGROUND/OBJECTIVE: Although previous studies reported the relationship between psoriasis and herpes zoster, the number of study is not sufficient to support the conclusions. The purpose of this study was to evaluate the association between psoriasis and herpes zoster. METHODS: The data of a nationally representative Korean cohort collected in the Korean Health Insurance Review and Assessment (HIRA) System from 2002 to 2013 were used. Psoriasis was defined ≥ 2 International Classification of Diseases 10th revision (ICD-10) L40 codes. Among them, severe psoriasis was defined as psoriatic medication use, including acitretin, systemic corticosteroid, cyclosporine and methotrexate. Other psoriasis was defined as mild psoriasis. Herpes zoster was defined as ≥ 2 ICD-10 B02 codes or ≥ 1 B02 code with antiviral medication use. Psoriasis patients (n = 11 009) and control participants (n = 44 036) were matched 1:4 by age, sex, income and region of residence. A stratified Cox proportional hazard model was used stratified by age, sex, income and region of residence. Crude and adjusted hazard ratios (HRs) were calculated for the risk of herpes zoster in the total psoriasis group, mild psoriasis group, and severe psoriasis group and compared with those in each matched control group. RESULTS: The HR for herpes zoster was higher in the psoriasis group than in control group (adjusted HR = 1.22, 95% CI = 1.12-1.33, P < 0.001). The findings were consistent between the mild psoriasis and severe psoriasis patients and their matched controls, and between male psoriasis patients in all age groups and their matched male controls. CONCLUSIONS: Psoriasis may increase the risk of herpes zoster, especially in males.

Evaluation of Mortality and Morbidity According to Initial Symptoms in COVID-19 Patients Using Clinical Epidemiologic Data from the Korea Centers for Disease Control & Prevention.

Background and Objectives: This study aimed to investigate whether initial symptoms of COVID-19 are associated with mortality and morbidity. Materials and Methods: The data of 5628 laboratory-confirmed COVID-19 patients were collected by the Korea Centers for Disease Control and Prevention. The maximum level of morbidity during hospital admission was classified as mild or severe, and patient mortality was recorded. Clinical symptoms were categorized as respiratory, gastrointestinal, general, and neurologic symptoms. The hazard ratios (HRs) for clinical symptoms associated with mortality were analyzed using the Cox proportional hazards model. The odds ratios (ORs) for clinical symptoms associated with morbidity were analyzed using the logistic regression model. Results: Of the included COVID-19 patients, 15.4% (808/5253) were classified as having severe morbidity. Morbidity was related to the clinical symptoms of cough, sputum, shortness of breath, vomiting/nausea, diarrhea, fever, and altered mental status or confusion. According to the symptom categories, respiratory and general symptoms were related to high morbidity (OR = 1.41, 95% CI = 1.30-1.53, p < 0.001 for respiratory symptom and OR = 1.37, 95% CI = 1.18-1.59, p < 0.001 for general symptom). Mortality was associated with the clinical symptoms of shortness of breath, fever, and altered mental status or confusion. Among the symptom categories, respiratory symptoms were associated with a 1.17-fold increased HR for mortality (95% CI = 1.04-1.32, p = 0.008). Conclusions: Initial respiratory symptoms were related to high morbidity and mortality in COVID-19 patients.

Bidirectional association between GERD and asthma in children: two longitudinal follow-up studies using a national sample cohort.

BACKGROUND: The causal relationship between asthma and gastroesophageal reflux disease (GERD) is unknown in children. METHODS: The Korean Health Insurance Review and Assessment Service-National Sample Cohort 2002-2013 was used. The population age <15 years was selected. In study I, 86,096 asthmatic children were 1:1 matched with 86,096 control I participants. In study II, 532 GERD children were 1:2 matched with 1064 control II participants. The stratified Cox proportional hazard ratios for GERD in patients with asthma (study I) and asthma in patients with GERD (study II) were analyzed. RESULTS: In total, 0.7% (583/86,096) of the asthma group and 0.5% (430/86,096) of the control I group had GERD (P < 0.001). The asthma group demonstrated a 1.36 times higher HR for GERD than the control I group (95% CI = 1.20-1.54, P < 0.001). Subgroup analyses according to age and sex showed consistent results. In total, 15.0% (80/532) of the GERD group and 10.0% (106/1,064) of the control II group had asthma (P < 0.001). The GERD group showed a 1.62-fold higher HR for asthma than the control II group (95% CI = 1.21-2.18, P < 0.001). CONCLUSION: GERD and asthma demonstrated a bidirectional relationship in children.

Mortality and cause of death in physical activity and insufficient physical activity participants: a longitudinal follow-up study using a national health screening cohort.

BACKGROUND: Few studies have examined the association between physical activity (PA) and various causes of mortality in Korea. The aim of our study was to evaluate mortality and causes of death between PA and insufficient PA using Korean national cohort data. METHODS: The health screening cohort data from the Korean National Health Insurance Service-National Sample Cohort from 2009 to 2015 were used. 'PA' was determined if participants walked or performed moderate-intensity activity ≥5 d/week for ≥30 min, or vigorous-intensity activity ≥3 d/week for ≥20 min. Other participants were classified as 'insufficient PA'. The PA and insufficient PA groups were matched by age, sex, income, and region of residence in a 1:1 ratio. Causes of death were classified into 13 categories. Crude and adjusted hazard ratios (HRs) with 95% confidence intervals (CIs) for all mortality rates were analyzed using a stratified Cox proportional hazard model. Age, sex, income, and region of residence were stratified. Subgroup analyses were performed according to age, sex, and obesity status. The odds ratio according to the causes of death was calculated by the chi-square test. RESULTS: The adjusted HR for mortality in the PA group was 0.85 (95% CI = 0.82-0.88). In subgroup analyses according to age, sex, and obesity status, results were consistent with the main findings in < 60-year-old females, ≥ 60-year-old males and females, and in all subgroups by obesity. The death rate by neoplasm, mental diseases, neurologic disease, circulatory disease, respiratory disease, digestive disease, abnormal finding, and trauma were lower in the PA than the insufficient PA group. CONCLUSIONS: These results suggest that PA is inversely associated with mortality caused specifically by diseases reflected by mental, respiratory, cancer, and cardiovascular conditions. Additionally, PA is inversely associated with mortality compared to insufficient PA in all obesity status.

Herpes zoster does not increase the risk of sudden sensory neural hearing loss: a longitudinal follow-up study using a national sample cohort.

Objective: This study aimed to investigate the risk of sudden sensorineural hearing loss (SSNHL) in Herpes zoster patients from a representative population cohort.Design: A longitudinal follow-up studyStudy sample: Data were obtained from the Korean National Health Insurance Service-National Sample Cohort for the period from 2002 to 2013. We matched 61,702 subjects in the Herpes zoster group with subjects in a control group (246,808 subjects with no history of Herpes zoster) based on demographic factors (age, sex, income, and region of residence) and medical history (diabetes, dyslipidemia, and hypertension). The crude (simple) and adjusted hazard ratios (HRs) for Herpes zoster with SSNHL were analysed using the Cox-proportional hazard model.Results: Only 0.5% (338/61,364) of the Herpes zoster group and 0.7% (1664/245,144) of the control group showed SSNHL. The Herpes zoster group did not exhibit a higher rate of SSNHL (adjusted HR = 0.81, 95% CI = 0.72-0.91, p < 0.001) than the control group. In subgroup analyses, no age subgroups showed a significant risk of SSNHL in the Herpes zoster group.Conclusions: After adjusting for confounding factors, the risk of SSNHL did not increase in the Herpes zoster group compared with the control group.

Bidirectional analysis of the association between Ménière's disease and depression: Two longitudinal follow-up studies using a national sample cohort.

OBJECTIVE: This study aimed to delineate the causal relationship between Ménière's disease and depression. DESIGN: Two longitudinal follow-up studies. MAIN OUTCOME MEASURES: The 2002-2013 Korean National Health Insurance Service-Health Screening Cohort was used. In study I, Ménière's disease patients were 1:4 matched with the control I group for age group, sex, income group and region of residence, and the occurrence of depression was observed. In study II, the depression patients were 1:4 matched with the control II group for the same variables, and the occurrence of Ménière's disease was observed. The stratified Cox proportional hazard model was used. Subgroup analyses were performed according to age and sex. RESULTS: In study I, 6.9% (420/6044) of the Ménière's disease patients and 3.7% (885/24 176) of the control I participants experienced depression. The adjusted hazard ratio (HR) of Ménière's disease for depression was 1.94 (95% confidence intervals [CI] = 1.73-2.18, P < .001). In study II, 1.6% (490/31 649) of the depression patients and 1.0% (1240/126 596) of the control II participants were diagnosed with Ménière's disease. The adjusted HR of depression for Ménière's disease was 1.58 (95% CI = 1.43-1.76, P < .001). All age and sex subgroups demonstrated higher HRs of Ménière's disease for depression (study I) and depression for Ménière's disease (study II). CONCLUSION: Ménière's disease patients showed an increased likelihood of depression. Conversely, depression patients showed an elevated likelihood of Ménière's disease.

Short- and long-term neuropsychiatric outcomes in long COVID in South Korea and Japan.

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.

Quantification of identifying cognitive impairment using olfactory-stimulated functional near-infrared spectroscopy with machine learning: a post hoc analysis of a diagnostic trial and validation of an external additional trial.

BACKGROUND: We aimed to quantify the identification of mild cognitive impairment and/or Alzheimer's disease using olfactory-stimulated functional near-infrared spectroscopy using machine learning through a post hoc analysis of a previous diagnostic trial and an external additional trial. METHODS: We conducted two independent, patient-level, single-group, diagnostic interventional trials (original and additional trials) involving elderly volunteers (aged > 60 years) with suspected declining cognitive function. All volunteers were assessed by measuring the oxygenation difference in the orbitofrontal cortex using an open-label olfactory-stimulated functional near-infrared spectroscopy approach, medical interview, amyloid positron emission tomography, brain magnetic resonance imaging, Mini-Mental State Examination, and Seoul Neuropsychological Screening Battery. RESULTS: In total, 97 (original trial) and 36 (additional trial) elderly volunteers with suspected decline in cognitive function met the eligibility criteria. The statistical model reported classification accuracies of 87.3% in patients with mild cognitive impairment and Alzheimer's disease in internal validation (original trial) but 63.9% in external validation (additional trial). The machine learning algorithm achieved 92.5% accuracy with the internal validation data and 82.5% accuracy with the external validation data. For the diagnosis of mild cognitive impairment, machine learning performed better than statistical methods with internal (86.0% versus 85.2%) and external validation data (85.4% versus 68.8%). INTERPRETATION: In two independent trials, machine learning models using olfactory-stimulated oxygenation differences in the orbitofrontal cortex were superior in diagnosing mild cognitive impairment and Alzheimer's disease compared to classic statistical models. Our results suggest that the machine learning algorithm is stable across different patient groups and increases generalization and reproducibility. TRIAL REGISTRATION: Clinical Research Information Service (CRiS) of Republic of Korea; CRIS numbers, KCT0006197 and KCT0007589.

Association between antidiabetic drugs and the incidence of atrial fibrillation in patients with type 2 diabetes: A nationwide cohort study in South Korea.

BACKGROUND: Although diabetes is a risk factor for atrial fibrillation (AF), studies on the AF risk according to the antidiabetic drugs are lacking. This study evaluated the effects of antidiabetic drugs on AF incidence in Korean patients with type 2 diabetes. METHODS: We included 2,515,468 patients with type 2 diabetes from the Korean National Insurance Service database without a history of AF who underwent health check-ups between 2009 and 2012. Newly diagnosed AF incidence was recorded until December 2018 according to the main antidiabetic drug combinations used in the real world. RESULTS: Of the patients included (mean age, 62 ± 11 years; 60 % men), 89,125 were newly diagnosed with AF. Metformin (MET) alone (hazard ratio [HR] 0.959, 95 % CI 0.935-0.985) and MET combination therapy (HR < 1) significantly decreased the risk of AF compared to the no-medication group. The antidiabetic drugs consistently showing a protective effect against AF incidence were MET (HR 0.977, 95 % CI 0.964-0.99) and thiazolidinedione (TZD; HR 0.926, 95 % CI 0.898-0.956), even after adjusting for various factors. Moreover, this protective effect was more remarkable with MET and TZD combination therapy (HR 0.802, 95 % CI 0.754-0.853) than with other drug combinations. In the subgroup analysis, the preventive effect of MET and TZD treatment against AF remained consistent, regardless of age, sex, duration, and diabetes severity. CONCLUSION: The combination therapy of MET and TZD is the most effective antidiabetic drug for preventing AF in patients with type 2 diabetes.

National Trends in Sadness, Suicidality, and COVID-19 Pandemic-Related Risk Factors Among South Korean Adolescents From 2005 to 2021.

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 ß, 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 ß, 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.

Breastfeeding and impact on childhood hospital admissions: a nationwide birth cohort in South Korea.

Benefits of breastfeeding for both the mother and the child are well established, but a comprehensive and robust study to investigate the protective effect of breastfeeding and attenuated time effect stratified by cause of morbidity are lacking. This study is based on the nationwide birth cohort in Korea that includes data on all infants born from 2009 to 2015. Of 1,608,540 children, the median follow-up period was 8.41 years (interquartile range, 6.76-10.06). When compared to children with fully formula feeding, the hospital admission rate was 12% lower in those with partially breastfeeding and 15% lower in those with exclusive breastfeeding. The apparent protective effect of breastfeeding was reduced with increasing age. Our study provides potential evidence of the beneficial association of breastfeeding on subsequent hospital admissions. The protective effect declined over time as the children grew older. Encouraging any breastfeeding for at least the first 6 months among infants is an important public health strategy to improve overall child health.