Consumption of Sugar-Sweetened Beverages before 2 Years of Age and Attention-Deficit/Hyperactivity Disorder.

INTRODUCTION: This study examined the association between sugar-sweetened beverage consumption before the first 24 months of life and attention-deficit/hyperactivity disorder (ADHD). METHODS: A population administrative cohort study was conducted in Korea (2008-2019) using linked national insurance data and a health screening survey. The cohort included 25,305 children in the exposed group with high sugar-sweetened beverage drinks (≥200 mL) and 339,931 in the reference groups (<200 mL) at 24 months of age. The primary outcome was the development of ADHD based on the International Classification of Disease (ICD) codes. Cox proportional model was used to identify the association between sugar-sweetened beverage consumption during early childhood and the later development of ADHD while controlling for multiple risk factors. RESULTS: Over a mean follow-up period of 9.2 years, the incidence rates of ADHD were 29.6 and 23.8 per 10,000 person-years in the exposed and reference groups, respectively. Compared with the reference group, children consuming high-sugar drinks were at an increased risk of ADHD (adjusted hazard ratio 1.17, 95% confidence interval [CI] 1.08-1.27). These associations remained significant even after applying alternative ADHD definitions or adjusting for confounding variables. CONCLUSION: Children who consume sweetened beverages during early childhood are at increased risk of developing ADHD later in life.

Age-related effects of Mycoplasma pneumoniae infection and subsequent asthma exacerbation in children.

BACKGROUND: Mycoplasma pneumoniae causes community-acquired pneumonia in children and increases asthma risk, but large studies are lacking. OBJECTIVE: To assess the link between M. pneumoniae infection and to asthma exacerbation, in children with allergies, and age of infection impact. METHODS: This retrospective cohort study analyzed medical records of South Korean children between January 2002 and December 2017. The study's exposure was hospitalization with an M. pneumoniae-related diagnosis, and the outcome was defined as asthma exacerbation, confirmed by hospitalization at least 6 months after M. pneumoniae infection, with alternative validation using asthma diagnosis and systemic steroid prescription records. Hazard ratios (HRs) for asthma exacerbation risk were estimated for the matched cohort using a Cox proportional hazards model stratified by allergic comorbidities. Time-dependent covariates and age-stratified exposure groups were used to calculate odds ratios. RESULTS: The study included 84,074 children with M. pneumoniae infection and 336,296 unexposed children. Follow-up for 12.2 ± 2.3 years found the exposed group had a significant risk of asthma exacerbation (HR 2.86, 95% confidence interval [CI] 2.67-3.06) regardless of allergic comorbidities. The risk was highest (over threefold) in children infected between 24 and 71 months. Sensitivity analysis using an alternative definition of the outcome showed an HR of 1.38 (95% CI 1.35-1.42), further supporting the association between M. pneumoniae infection and asthma exacerbation. CONCLUSION: M. pneumoniae infection was significantly associated with an increased risk of subsequent asthma exacerbation regardless of allergic comorbidities. Further research needed for understanding and confirmation.

Neurodevelopment in Term Infants with Normal Birthweight following Postnatal Systemic Steroid Exposure.

INTRODUCTION: Studies investigating the potential impact of systemic steroid exposure during early infancy on neurological development in full-term infants with normal birth weight are lacking. METHODS: This population-based administrative cohort study used data of national health insurance and a health-screening program for infants and children and included full-term infants who were born in Korea between 2008 and 2012 with normal birth weight and did not have any specific perinatal or neurodevelopmental diseases. The prescription of systemic steroids within the first 3 months of age was mainly considered. The neurological development of children was assessed using the Korean Development Screening Test (K-DST) at 6 years of age. To balance the baseline characteristics of the control and exposed groups, stabilized inverse probability of treatment weighting with trimming was performed in the main cohort. Ordinal logistic regression was used to assess the association between systemic steroid exposure and unfavorable results in the K-DST. RESULTS: The control and exposure groups had 246,168 and 5,083 children, respectively. The K-DST suggested unfavorable results in 8.1% and 8.6% children in the control and exposure groups, respectively (weighted odds ratio, 95% confidence interval, 1.03, 0.93-1.14). When each domain of the K-DST was considered separately, the risk of unfavorable results in the exposed group was not significantly different from that in the control group. CONCLUSIONS: No significant association was observed between exposure to systemic steroids during early infancy and neurodevelopmental impairment at 6 years of age.

Investigating the occurrence of autoimmune diseases among children and adolescents hospitalized for Mycoplasma pneumoniae infections.

Background: Mycoplasma pneumoniae infection is common in the general population and may be followed by immune dysfunction, but links with subsequent autoimmune disease remain inconclusive. Objective: To estimate the association of M. pneumoniae infection with the risk of subsequent autoimmune disease. Methods: This retrospective cohort study examined the medical records of South Korean children from 01/01/2002 to 31/12/2017. The exposed cohort was identified as patients hospitalized for M. pneumoniae infection. Each exposed patient was matched with unexposed controls based on birth year and sex at a 1:10 ratio using incidence density sampling calculations. The outcome was subsequent diagnosis of autoimmune disease, and hazard ratios (HRs) were estimated with control for confounders. Further estimation was performed using hospital-based databases which were converted to a common data model (CDM) to allow comparisons of the different databases. Results: The exposed cohort consisted of 49,937 children and the matched unexposed of 499,370 children. The median age at diagnosis of M. pneumoniae infection was 4 years (interquartile range, 2.5-6.5 years). During a mean follow-up time of 9.0 ± 3.8 years, the incidence rate of autoimmune diseases was 66.5 per 10,000 person-years (95% CI: 64.3-68.8) in the exposed cohort and 52.3 per 10,000 person-years (95% CI: 51.7-52.9) in the unexposed cohort, corresponding to an absolute rate of difference of 14.3 per 10,000 person-years (95% CI: 11.9-16.6). Children in the exposed cohort had an increased risk of autoimmune disease (HR: 1.26; 95% CI: 1.21-1.31), and this association was similar in the separate analysis of hospital databases (HR: 1.25; 95% CI 1.06-1.49). Conclusion: M. pneumoniae infection requiring hospitalization may be associated with an increase in subsequent diagnoses of autoimmune diseases.

Association between statin use and the prognosis of hepatocellular carcinoma after resection: a nationwide cohort study.

Background: The majority of patients with hepatocellular carcinoma (HCC) following hepatic resection experience tumor recurrence. Statin use is associated with a reduced risk of HCC development; however, the association between statin use and the prognosis of HCC after resection remains unclear. We aimed to investigate the effect of statin use on the prognosis after hepatic resection among patients with HCC. Methods: A nationwide cohort study was performed with data from the National Health Insurance Service Database in Korea. Among 65,101 HCC patients who underwent hepatic resection between January 2002 and December 2017, we included 21,470 patients. For validation, a hospital-based cohort of 3366 patients with very early or early-stage HCC who received curative-intent hepatic resection between January 2010 and December 2018 was analyzed. Recurrence-free survival (RFS) and overall survival (OS) was compared between statin users and non-users. Findings: Among the nationwide cohort of 21,470 patients, 2399 (11.2%) used statins and 19,071 (88.8%) did not. Among the hospital cohort of 3366 patients, 363 (10.8%) used statins and 3003 (89.2%) did not. In the propensity score-matched nationwide cohort, statin users had better RFS (hazard ratio [HR], 0.60; 95% confidence interval [CI], 0.56-0.64; P < 0.001) and OS (HR, 0.49; 95% CI, 0.45-0.53; P < 0.001), with a duration-response relationship. In the propensity score-matched validation hospital cohort, statin treatment was significantly associated with better RFS (HR, 0.73; 95% CI, 0.59-0.90; P = 0.003) and OS (HR, 0.48; 95% CI, 0.32-0.72; P < 0.001). The beneficial effects of statins were more prominent in non-cirrhotics, tumors sized ≥3 cm, tumors with microscopic vascular invasion, or early HCC recurrence (<2 years after resection). Interpretation: Statin use was associated with a better prognosis in a population-based cohort of patients with HCC after hepatic resection, which was further validated in a large hospital-based cohort. Funding: Asan Institute for Life Sciences and Corporate Relations; Korean Association for the Study of the Liver.

Effect of antihypertensive medications on the risk of open-angle glaucoma.

The purpose of this study was to identify the effect of antihypertensive medication on risks of open-angle glaucoma (OAG) among patients diagnosed with hypertension (HTN). A total of 5,195 patients, who were diagnosed with HTN between January 1, 2006 and December 31, 2015, and subsequently diagnosed with OAG, were selected for analysis. For each OAG patient, 5 non-glaucomatous, hypertensive controls were matched (n = 25,975) in hypertension diagnosis date, residential area, insurance type and economic status. Antihypertensive medications were stratified into 5 types: angiotensin converting enzyme inhibitor (ACEi), angiotensin receptor blockers (ARB), calcium channel blockers (CCB), ß-blockers and diuretics. Relative risks were calculated. After adjusting for age, sex, body mass index, lifestyle, comorbidities, blood pressure (BP), follow-up duration, and use of other types of antihypertensive drugs, ARB and CCB were found to slightly increase OAG risks (RR 1.1087 (95% CI 1.0293-1.1942); 1.0694 (1.0077-1.1349), respectively). Combinations of ARB with diuretics (1.0893 (1.0349-1.1466)) and CCB (1.0548 (1.0122-1.0991)) also increased OAG risks. The risks for OAG were found to increase by antihypertensive medication use, but the effects appeared to be small. Further studies are necessary to identify the associations of increased BP, medication and therapeutic effect with OAG.

Associations between Delayed Introduction of Complementary Foods and Childhood Health Consequences in Exclusively Breastfed Children.

The timing of complementary food (CF) introduction is closely related to childhood health, and it may vary depending on the region, culture, feeding type, or health condition. Despite numerous studies on the benefits of breastfeeding and the optimal timing of CF introduction, there have been limited investigations regarding delayed CF introduction in exclusively breastfed children. We compared an exposed group (CF introduction ≥7 months) with a reference group (CF introduction at 4 -< 7 months) regarding hospital admission, disease burden, and growth until age 10. Data from a nationwide population-based cohort study involving children born between 2008 and 2012 in the South Korea were analyzed. The final cohort comprised 206,248 children (165,925 in the exposed group and 40,323 in the reference group). Inverse probability of treatment weighting with propensity score matching was used to balance baseline health characteristics in the comparison groups. We estimated the incident risk ratios (IRR) for outcomes using modified Poisson regression and weighted odds ratios (weighted ORs) and their 95% confidence intervals (CIs) using multinomial logistic regression. The exposed group was associated with low height-for-age z-score (HAZ) (IRR (95% CI) for -1.64 < HAZ ≤ -1.03: 1.11 (1.08 to 1.14); HAZ ≤ -1.64: 1.21 (1.14 to 1.27)) and frequent (≥6 events) hospitalizations (weighted OR 1.18 (1.09 to 1.29). The rates of hospital admission, death, and specific medical conditions did not differ between groups. However, delaying the introduction of CF until seven months in exclusively breastfed infants was associated with frequent hospitalization events and lower heights.

Association between First-Generation Antihistamine Use in Children and Cardiac Arrhythmia and Ischemic Heart Disease: A Case-Crossover Study.

Cardiotoxicity from first-generation H1-antihistamines has been debated since the 1990s. However, large-scale studies on this topic in a general pediatric population are lacking. This study aimed to assess the association between first-generation H1-antihistamine use and cardiovascular events in a nationwide pediatric population. In this case-crossover study, the main cohort included children with cardiovascular events from the National Health Insurance Service database (2008-2012 births in Korea) until 2018. The second cohort excluded children with specific birth histories or underlying cardiovascular diseases from the main cohort. Cardiovascular events of interest included cardiac arrhythmia and ischemic heart disease. Odds ratios (ORs) of cardiovascular events were estimated using conditional logistic regression models, comparing first-generation H1-antihistamine use during 0-15 days before cardiovascular events (hazard period) with use during 45-60 and 75-90 days before events (control periods). Among the participants, 1194 (59.9%) were aged 24 months to 6 years, and 1010 (50.7%) were male. Cardiovascular event risk was increased among users of first-generation H1-antihistamines (adjusted OR [aOR], 1.201; 95% confidence interval, 1.13-1.27). Significant odds of cardiovascular events persisted within 10 and 5 days (aOR, 1.25 and 1.25). In the second cohort, the association was comparable with that in the main cohort. Our findings indicate that cardiovascular event risk is increased in children who are administered first-generation H1-antihistamines.

Association between atopic dermatitis and school readiness in preschool children.

BACKGROUND: Although atopic dermatitis (AD) in children affects diverse stages of life, no studies have reported on the association between school readiness and AD. METHODS: This study used Korean National Health Insurance data and the Health Screening Program for Infants and Children. Among all children born between 2008 and 2012 in Korea, those who were assessed for school readiness through questionnaires in a health screening program performed at 54 and 60 months old were enrolled. AD was defined based on the International Classification of Diseases codes, with two or more prescriptions of topical corticosteroids during the first 54-60 months of life. The primary outcome was the association between school readiness and AD. The questionnaire relating to school readiness comprised six items - cognitive skills, social development, activeness, concentration, emotional development, and language skills. Logistic regression analysis was used to identify the associations between school readiness and AD. RESULTS: This study included 239,673 children without AD and 38,229 children with AD. The average age at which school readiness was assessed was 4.8 years. AD was associated with vulnerability in activeness (adjusted odds ratio: 1.127; 95% confidence interval: 1.071-1.186) and concentrations (1.170; 1.093-1.254). The impact of AD on concentrations showed consistent results regardless of sex, exposure to systemic corticosteroids and antihistamines, and age at the diagnosis of AD. CONCLUSIONS: Children with AD have vulnerability in school readiness in the aspects of activeness and concentration.

Rotavirus-Associated Hospitalization in Children With Subsequent Autoimmune Disease.

Importance: Rotavirus infection is a common cause of gastroenteritis in children that can trigger autoimmune processes, but the nature of this interaction remains poorly understood. Objective: To estimate the association of rotavirus infection with the risk of subsequent autoimmune disease. Design, Setting, and Participants: This population-matched cohort study used data from children and adolescents (aged younger than 18 years) in South Korea (national registers from January 1, 2002, to December 31, 2017). The cohort consisted of 86 157 patients in the exposure group who had experienced rotavirus-associated hospitalization and the same number of matched patients in the unexposed group. Data analyses were from May 1, 2020, through October 20, 2022. Exposures: Hospitalization for rotavirus infection. Main Outcomes and Measures: The main outcome was childhood autoimmune diseases during the study defined by diagnoses according to the National Health Insurance Database. Hazard ratios (HRs) with 95% CIs for autoimmune diseases were estimated using a Cox model, with multiple confounding factors controlled. Results: This cohort study consisted of 1 914 461 individuals born in South Korea from 2002 to 2005 who were potentially eligible. After exclusions, there were 86 517 individuals in the exposed group and 86 517 in the unexposed group after 1:1 incidence density sampling. The study included 49 072 (57.0%) male patients. The median (IQR) age at diagnosis of rotavirus-associated hospitalization was 1.5 (0.9-2.7) years, and the HR for autoimmune disease in the exposed group was 1.24 (95% CI, 1.19-1.28) for a mean (SD) follow-up time of 12.1 (3.2) years. The use of more stringent definitions for exposure and outcomes in a multivariable stratified analysis also indicated that rotavirus-associated hospitalization was associated with an increased risk of subsequent autoimmune disease (HR, 1.22 [95% CI, 1.16-1.28]). Sensitivity analysis showed that individuals with rotavirus-associated hospitalization was related to multiple autoimmune syndromes (2 or more: HR, 1. 51 [95% CI, 1. 31-1. 73]; 3 or more: HR, 1. 79 [95% CI, 1.18-2.72]) and that the number of rotavirus-associated hospitalization were associated with higher risks for autoimmune disease in a dose-dependent manner (single hospitalization event: HR, 1.20 [95% CI, 1.16-1.24]; multiple events HR, 1.60 [95% CI, 1.49-1.72]). Conclusions and Relevance: Our results indicate that rotavirus-associated hospitalization is significantly associated with subsequent autoimmune disease during childhood. Clinicians should be aware of the heightened susceptibility to autoimmune disease in individuals with prior rotavirus-associated hospitalization.

Assessment of Neurodevelopment and Growth in Congenital Hypothyroidism: Serial 6-Year Follow-up Study of 408 Patients.

CONTEXT: The link between congenital hypothyroidism (CH) and neurodevelopment is suggested, yet studies applying quantifiable measures are lacking. Moreover, socioeconomic disparities and subtle variation in timing of approach make the relationship difficult to detect. OBJECTIVE: To evaluate associations between CH and abnormalities in neurodevelopment and growth and determine the critical period for intervention. METHODS: We utilized a nationwide database to conduct a longitudinal analysis of 919 707 children. Exposure to CH was identified using claims-based data. The primary outcome of interest was suspected neurodevelopmental disorder, as measured using the Korean Ages & Stages Questionnaires (K-ASQ) administered annually from 9 to 72 months of age. Secondary outcomes were height and BMI z-scores. After randomly matching cases and controls at a 1:10 ratio, we employed inverse probability of treatment weighting and generalized estimating equation models for our analyses. We conducted subgroup analysis based on the age of treatment initiation. RESULTS: The prevalence of CH in our population was 0.05% (n = 408). Relative to the control group, the CH group had higher risk of suspected neurodevelopmental disorders (propensity score-weighted odds ratio: 4.52; 95% CI: 2.91, 7.02), and significantly increased risk in each of the 5 K-ASQ domains. No time interactions were noted at any rounds for the outcomes according to when the neurodevelopmental assessment was conducted (all P for interaction >.05). The CH group also had higher risk for low height-for-age z-score, but not for elevated BMI-for-age z-score. In subgroup analysis, delayed medication for CH correlated with worse neurodevelopmental outcomes. CONCLUSION: The CH group had worse neurodevelopmental outcomes and reduced height-for-age z-score. Outcomes were worse when onset of treatment was increasingly delayed.

Acquired susceptibility to autoimmune diseases in pediatric patients with Escherichia coli infection: A population-matched retrospective cohort study.

BACKGROUND: Escherichia coli (E.coli) infection has been proposed to play an important role as an initial trigger in the development of autoimmunity via molecular mimicry. However, there has been no preliminary cohort study to establish the association of E.coli infection with autoimmune diseases. Therefore, we conducted a large scale, population-matched cohort study to determine the risk of autoimmune disease among patients with exposure to E.coli. METHODS: Utilizing the National Health Insurance Service database, we retrospectively analyzed a total of 259,875 Korean children that consisted of 23,625 exposed and 236,250 unexposed persons from January 1, 2002 to December 31, 2017. The exposed cohort was defined as patients diagnosed with E.coli infection. Unexposed controls were matched by birth year and sex at a 1:10 ratio for each exposed patient, using incidence density sampling. The primary outcome was autoimmune disease development. We used the Cox model to estimate the risks of autoimmune diseases among patients diagnosed with E.coli infection. RESULTS: Over a mean follow-up of 10 years, there were 1455 autoimmune disease cases among exposed patients (incidence rate, 63.6 per 10,000 person-years) and 11,646 autoimmune disease cases among unexposed persons (incidence rate, 50.4 per 10,000 person-years), with an adjusted hazard ratio (HR) of 1.254 (95% CI 1.187-1.325). E.coli infection was associated with increased risks of autoimmune diseases; Reactive arthritis, HR 1.487, 95% CI 1.131-1.956; Henoch Schönlein purpura, HR 1.265, 95% CI 1.050-1.524; Systemic lupus erythematosus, HR 1.838, 95% CI 1.165-2.898; Sjögren's syndrome, HR 2.002, 95% CI 1.342-2.987; IgA nephropathy, HR 1.613, 95% CI 1.388-1.874. Kaplan-Meier cumulative incidence curves also showed a significant association between E.coli infection and incident autoimmune disease (p < 0.0001). This relationship was not only independent of demographic variables, but also remained consistent across various sensitivity analyses. On the other hand, patients with longer hospital stay for E.coli infection were at a higher risk of autoimmune disease (p = 0.0003), and the risk of autoimmune disease also tended to increase, as the frequency of E.coli infection was higher. Moreover, the relative risk of autoimmune disease seemed to be attenuated by use of antibiotics and a history of intestinal infectious disease, but elevated by coexistence of other autoimmune diseases. CONCLUSIONS: Our cohort study indicates that E.coli infection was significantly associated with increased susceptibility to autoimmune diseases, even after adjusting for different factors. Thus, among environmental factors, a previous history of E.coli infection could be a predisposing risk factor in the development of autoimmune diseases.

Association Between Receipt of General Anesthesia During Childhood and Attention Deficit Hyperactive Disorder and Neurodevelopment.

BACKGROUND: There are inconsistent reports regarding the association between general anesthesia and adverse neurodevelopmental and behavioral disorders in children. METHODS: This nationwide administrative cohort study included children born in Korea between 2008 and 2009, and followed until December 31, 2017. The cohort included 93,717 participants who received general anesthesia with endotracheal intubation (ETI) who were matched to unexposed subjects in a 1:1 ratio. General anesthesia was defined by National Health Insurance Service treatment codes with intratracheal anesthesia, and the index date was the first event of general anesthesia. The primary outcome was attention deficit hyperactive disorder (ADHD), which was defined as at least a principal diagnosis of 10th revision of the International Classification of Diseases code F90.X after the age of 72 months. Neurodevelopment, which was assessed using a developmental screening test (Korean-Ages and Stages Questionnaire [K-ASQ]), was a secondary outcome. The K-ASQ is performed annually from 1 to 6 years of age and consists of 5 domains. The association between general anesthesia and ADHD was estimated using a Cox hazard model, and its association with neurodevelopment was estimated using a generalized estimation equation, with control for multiple risk factors beyond 1 year after the index date. RESULTS: The median age at the index date was 3.8 (95% confidence interval [CI], 1.7-5.8) years, and there were 57,625 (61.5%) men. During a mean follow-up period of 5 years, the incidence rate of ADHD was 42.6 and 27.7 per 10,000 person-years (PY) in the exposed and unexposed groups, respectively (absolute rate difference 14.9 [95% CI, 12.5-17.3] per 10,000 PY). Compared to the unexposed group, the exposed group had an increased risk of ADHD (adjusted hazard ratio, 1.41 [95% CI, 1.30-1.52]). In addition, a longer duration of anesthesia with ETI and more general anesthesia procedures with ETI were associated with greater risk of ADHD. General anesthesia with ETI was also associated with poorer results in the K-ASQ. CONCLUSION: Administration of general anesthesia with ETI to children is associated with an increased risk of ADHD and poor results in a neurodevelopmental screening test.

Relationship Between Feeding to Sleep During Infancy and Subsequent Childhood Disease Burden.

OBJECTIVE: To investigate the association of feeding to sleep during infancy and subsequent childhood health burdens. STUDY DESIGN: Information was collected from the parents of children who participated in the national health screening survey when the child was 9-12 months old. The exposure group included participants who were fed to sleep. The primary outcome was all-cause hospital admission (inpatient care, intensive care unit [ICU] admission, or general anesthesia) after age 24 months. Secondary outcomes were subsequent childhood diseases (ie, adenoidectomy and/or tonsillectomy, nasal polyps, allergic rhinitis, acute otitis media, asthma, pneumonia, and aspiration pneumonia), and growth status, as measured by weight-to-age and height-to-age z-scores. RESULTS: The study cohort consisted of 224 075 children who participated in the health screening program, 29 392 of whom (13.1%; 51% males) were fed to sleep. Exposure was associated with an increased risk of all-cause hospitalization after age 24 months (hazard ratio [HR], 1.05; 95% CI, 1.03-1.07), but not with admission to an ICU or receipt of general anesthesia. This also was related to adenoidectomy and/or tonsillectomy (HR, 1.08; 95% CI, 1.01-1.15), dental caries (HR, 1.32; 95% CI, 1.23-1.40), asthma (HR, 1.14; 95% CI, 1.14-1.24), pneumonia (HR, 1.10; 95% CI, 1.07-1.13), overweight (HR, 1.06; 95% CI, 1.03-1.09), and obesity (HR, 1.11; 95% CI, 1.06-1.16). CONCLUSIONS: Several adverse health outcomes are related to feeding to sleep during early childhood.

Growth pattern during early infancy, body mass index during childhood and childhood asthma.

BACKGROUND: There is a lack of longitudinal studies of associations between growth from infancy to childhood and asthma development. OBJECTIVE: The objective of the study was to investigate the effects of weight change during infancy, body mass index (BMI) and the interaction of these factors on the risk of childhood asthma. METHODS: We enrolled children born in 2008 and 2009 at full-term and with normal birth weight. The weight change in infancy was grouped into slow, on-track and rapid. BMI status in childhood was stratified into low, normal and high groups and used as a time-varying variable. The outcome was asthma, defined as two or more diagnoses of asthma separated by at least 1 year after 2 years of age. The risk of asthma was assessed using Cox proportional hazard regression, with adjustment for sex, residence area at birth, economic status and feeding types in infancy. RESULTS: Of 917,707 children born in Korea in 2008 and 2009, 271,871 were eligible for analysis. The risk of asthma was greater in groups with low birth weight (aHR 1.06, 95% CI 1.04 to 1.08), rapid body weight change during early infancy (aHR 1.08, 95% CI 1.07 to 1.10) and high BMI during childhood (aHR 1.06, 95% CI 1.04-1.08). The interaction of weight change during early infancy with BMI during childhood was significant for asthma (p < .01). Rapid weight gain in infancy was associated with lower risk of asthma in those with low BMI during childhood; had no association with asthma in those with normal BMI during childhood; and was associated increased asthma risk in those with high BMI during childhood-aHR 1.26 (95% CI 1.19 to 1.33) and aHR 1.33 (95% CI 1.12 to 1.56) compared with on-track and slow infant weight gain, respectively. CONCLUSION: Low birth weight, high BMI during childhood and, in those with high childhood BMI, rapid weight gain during early infancy are associated with increased risk of childhood asthma.

Infantile Colic and the Subsequent Development of the Irritable Bowel Syndrome.

Background/Aims: Little is known about the association between infantile colic and the later onset of irritable bowel syndrome (IBS). Methods: This study examined all 917 707 children who were born in Korea between 2007 and 2008. Infantile colic was defined with 1 or more diagnoses of ICD-10 code R10.4 or R68.1 at the age of 5 weeks to 4 months, and infants with a diagnosis of infantile colic and without were allocated into the infantile colic group and the control group. IBS was defined as 2 or more diagnoses of ICD-10 code K58.X after 4 years of age. Each child was traced until 2017. The risk of IBS with infantile colic was evaluated using a Cox proportional hazards model with propensity score inverse probability of treatment weighting (IPTW). Results: After IPTW, 363 528 and 359 842 children were allocated to the control group and the infantile colic group, respectively. The infantile colic group had a higher risk of developing IBS in childhood (hazard ratio [95% CI], 1.12 [1.10 to 1.13]) than the control group. Moreover, the subgroup analyses according to the feeding status, birth weight, sex, or economic status, showed that the risk of IBS with former infantile colic remained statistically significant. Conclusions: Children with a diagnosis of infantile colic during the infant period had a significant risk of developing IBS after 4 years of age. Understanding the pathogenesis of infantile colic in the neonatal period may reduce the prevalence and severity of functional gastrointestinal disorders from childhood to adolescence to adulthood.

Long-Term Observational Outcomes after Total Correction of Congenital Heart Disease in Korean Patients with Down Syndrome: A National Cohort Study.

Background: In the present study, the population prevalence and postoperative morbidity and mortality in Down syndrome patients who underwent total correction for congenital heart disease were investigated using data from a large national cohort. Methods: Retrospective administrative data from 2,395,966 participants born between 2008 and 2012 were acquired from the National Investigation of Birth Cohort in Korea. Among Down syndrome patients, 58.3% had congenital heart disease and 32.3% underwent total correction. Propensity score matching (maximum 1:1) and stabilized inverse probability treatment weighting (IPTW) were performed for each group (153 Down syndrome patients and 4482 non-Down syndrome patients). Results: T late mortality rate was significantly higher in the Down syndrome group than in the non-Down syndrome group (8.1% vs. 3.8%). No differences were observed in postoperative heart failure and arrhythmias, but pulmonary hypertension was significantly greater in the Down syndrome group than in the non-Down syndrome group (26.9% vs. 7.0%). The length of hospitalization was longer in the Down syndrome group than in the non-Down syndrome group (14 days vs. 11 days; interquartile range (IQR): 10−25 vs. 6−19; p < 0.0001). After total correction, readmission frequency for any reason was minimally but statistically significantly higher in the Down syndrome group compared to the non-Down syndrome group (5 times vs. 5 times; IQR: 3−8 vs. 4−9; p < 0.0001). However, the number of emergency room visits was minimally but significantly lower in the Down syndrome group compared to the non-Down syndrome group (2 visits vs. 2 visits (IQR): 2−7 vs. 1−4; p = 0.016). Conclusions: Down syndrome patients with congenital heart disease undergoing total correction showed pulmonary hypertension after surgery, longer length of hospitalization, frequent hospitalization after surgery, and a higher rate of late mortality.

Association of clinical and social factors with risk of fracture in children with atopic dermatitis.

BACKGROUND: Children with atopic dermatitis (AD) have multiple risk factors for accidental fractures, injuries that can lead to significant morbidity and mortality. However, little is known about the factors that mediate the relationship between AD and fracture in children. OBJECTIVE: Our purpose was to examine the association of AD with fracture and to identify potential mediating factors. METHODS: This retrospective cohort study examined children with and without AD from a longitudinal matched cohort database of 353,040 children registered in the national health insurance service and participated in the national health-screening program of Korea. We defined AD using medical claims and medication prescription records. We investigated accidental fracture events between the index date and the end of follow-up in a propensity score-matched cohort. Pre-specified subgroup analyses considered fractures in four different regions of the body. The mediating effects of 10 possible clinical factors (including the use of antihistamines and systemic corticosteroids) and social factors (including nutritional status and parental safety awareness) were determined. RESULTS: There were 145,704 participating children, 20% with AD and 49% girls. Fractures occurred in 6,652 of the children with AD (23%, mean age: 64.6 ± 29.2 months) and in 24,698 of the control group (21%, mean age 65.0 ± 28.9 months). Children with AD had an 8% greater risk of fracture events overall (adjusted relative risk [aRR]: 1.08, 95% CI: 1.05-1.10). In subgroup analysis, AD was related to increased rates of skull and facial bone fracture (aRR: 1.09, 95% CI: 1.04-1.14), for trunk including vertebrae (aRR: 1.58, 95% CI: 1.22- 2.05), and for distal limbs (aRR: 1.11, 95% CI: 1.07-1.15). However, the relationship with proximal limb fracture was insignificant. Duration of systemic corticosteroid prescription was the largest mediating factor, followed by duration of antihistamine prescription, and infant feeding practices. In particular, the duration of systemic corticosteroid prescription was significantly associated with fracture events (incidence: 20.1% at the 25th percentile and 23.6% at the 75th percentile; difference: 3.4% [95% CI: 2.8-4.0%]). CONCLUSIONS: Children with AD were related to increased fracture events. The key factors with mediating effects were systemic use of corticosteroid and antihistamine. Infant feeding practices had weaker mediating effects.

Growth in Exclusively Breastfed and Non-exclusively Breastfed Children: Comparisons with WHO Child Growth Standards and Korean National Growth Charts.

BACKGROUND: This study examined the relationship of infant feeding with anthropometric indices of children during their first six years of life relative to the Korean National Growth Charts (KNGC) and the World Health Organization Child Growth Standards (WHO-CGS). METHODS: The study population consisted of 547,669 Korean infants and children who were 6 months-old to 6 years-old (born in 2008-2009) and participated in the National Health Screening Program for Infants and Children. Data on height, weight, and type of feeding during the first 6 months (exclusively breastfed [BF] vs. mixed- or formula-fed [FF]) were analyzed. RESULTS: BF boys and girls were significantly shorter and lighter than FF counterparts from the age of 6 months to 4 years, but these differences were not significant after the age of 4 years. BF boys and girls only had significantly lower body mass index at the age of 2 years. Under the age of 2 years 6 months, and especially under the age of 1 year, BF boys and girls were significantly taller and heavier than the 50th percentile values of the 50th percentile value of the WHO-CGS. CONCLUSION: In this study using large-scaled national data, Korean breastfed children are shorter and lighter by 3 years 6 months-4 years 6 months, but afterward, there is no significant difference from those who had mixed- or formula-feeding. Substantial disparities in the anthropometric indices of Korean infants under the age of 1 compared to KNCG and WHO-CGS were found, regardless of their infantile feeding types. Our results emphasize the importance of constructing a nationwide reference chart based on actual measurements of BF Korean infants.