Association of Wheezing Requiring Hospitalization Before 2 Years of Age With Autoimmune Diseases During Childhood: A 15-Year Follow-up Study From Birth.

PURPOSE: Wheezing in early life is most frequently caused by viral lower respiratory tract illnesses, constituting a significant disease burden in children. This study aimed to investigate the association of wheezing in early life with autoimmune diseases throughout childhood. METHODS: A population-matched retrospective cohort study was conducted in Korea between 2002 and 2017. The cohort comprised 34,959 children admitted with viral wheezing before 2 years of age and an equal number of the matched unexposed children born in 2002 and 2003. Exposed infants were defined as those hospitalized for bronchiolitis or bronchial asthma before the age of 2. Unexposed controls were matched by sex and birth year at a 1:1 ratio, using incidence density sampling. A Cox proportional hazard model controlled for multiple risk factors was employed. RESULTS: The median age at hospitalization for wheeze was 9 months (interquartile range, 5-15 months), and 63% of the exposed infants were male. Over the mean 15-year follow-up period, the incidence rate of autoimmune diseases was 74.0 and 62.2 per 10,000 person-years in the exposed and matched unexposed cohorts, respectively. The adjusted hazard ratio for any autoimmune disease in the exposed cohort was 1.15 (95% confidence interval, 1.09-1.23) in comparison with the unexposed cohort. The exposed cohort revealed an augmented risk for specific autoimmune diseases, including juvenile idiopathic arthritis, Kawasaki disease, Henoch-Schönlein purpura, psoriasis, idiopathic thrombocytopenic purpura, and immunoglobulin A nephropathy. Risks were heightened for children with multiple wheezing episodes or a persistent wheezing episode after the age of 2 years. CONCLUSIONS: This research identifies associations between early-life wheeze and the development of autoimmune diseases in childhood. Understanding these relationships can aid in recognizing the underlying pathophysiology of early-life wheeze and childhood autoimmune diseases, contributing to management strategies for these conditions.

Viral respiratory infections requiring hospitalization in early childhood related to subsequent asthma onset and exacerbation risks.

Viral lower respiratory tract infections (LRTIs), including rhinovirus and respiratory syncytial virus during early childhood, have been linked to subsequent asthma. However, the impact of other respiratory viruses remains unclear. We analyzed nationwide Korean data from January 1, 2008, to December 31, 2018, utilizing the national health insurance database. Our study focused on 19 169 meticulously selected children exposed to severe respiratory infections requiring hospitalization with documented viral pathogens, matched with 191 690 unexposed children at a ratio of 1:10 using incidence density sampling. Our findings demonstrate that asthma exacerbation rates were higher among the exposed cohort than the unexposed cohort over a mean follow-up of 7.8 years. We observed elevated risks of asthma exacerbation and newly developed asthma compared to the unexposed cohort. Hospitalization due to rhinovirus, respiratory syncytial virus, influenza, metapneumovirus, and adenovirus was related to increased asthma exacerbations. Notably, we found a stronger association in cases of multiple LRTI hospitalizations. In conclusion, our study shows that early childhood respiratory viral infections are related to subsequent asthma exacerbations and new asthma diagnoses.

First-Generation Antihistamines and Seizures in Young Children.

Importance: The widespread use of antihistamines in children for treatment of common cold symptoms and their central nervous system effects, like drowsiness, underscore the importance of being aware of the associated risks. Objective: To assess associations between prescriptions of first-generation antihistamines and seizures in children using a comprehensive and nationwide dataset. Design, Setting, and Participants: This cohort study used a self-controlled case-crossover design. Data were obtained from the National Health Insurance Service database in Korea. Children born between January 1, 2002, and December 31, 2005, who visited the emergency department for seizure events (International Statistical Classification of Diseases and Related Health Problems, Tenth Revision, codes R56.8, G40, and G41) during the follow-up period were included. Follow-up was completed on December 31, 2019, and data were analyzed from June 3, 2023, to January 30, 2024. Exposure: First-generation antihistamine prescription. Main Outcomes and Measures: Primary outcome consisted of an index seizure event. Odds ratios (ORs) for seizure events were estimated using a conditional logistic regression model, comparing first-generation antihistamine prescription 1 to 15 days before seizure (hazard period) against control period 1 (31-45 days before the event) and control period 2 (61-75 days before the event) using the same period windows. Stratified analyses were conducted to examine the association with individual participant characteristics. Results: Of 11 729 children who had a seizure event, 3178 (1776 [55.9%] boys) were identified as having been prescribed antihistamines during the hazard or the control period, but not both. Seizure events were predominantly observed in children aged 6 to 24 months (985 [31.0%]) and 25 months to 6 years (1445 [45.5%]). During the hazard period, 1476 first-generation antihistamine prescriptions were recorded, in contrast to 1239 and 1278 prescriptions during control periods 1 and 2, respectively. After multiple confounder adjustments, first-generation antihistamine prescription was associated with an increased seizure event risk during the hazard period (adjusted OR [AOR], 1.22 [95% CI, 1.13-1.31]). Stratified subgroup analyses showed consistent results, particularly in children aged 6 to 24 months who were prescribed first-generation antihistamines having a higher risk (AOR, 1.49 [95% CI, 1.31-1.70]) than children aged 25 months to 6 years (AOR, 1.11 [95% CI, 1.00-1.24]; P = .04 for interaction). Furthermore, sensitivity analyses, including adjustment for exposure window periods, evaluation of new first-generation antihistamine prescriptions, comparison of control points from the same period 1 year prior, and exclusion of individuals using combination drugs, confirmed a similarly high risk. Conclusions and Relevance: In this cohort study, prescriptions for first-generation antihistamines were associated with a 22.0% higher seizure risk in children, especially in those aged 6 to 24 months. These findings emphasize the need for careful and judicious prescription of first-generation antihistamines in young children and underline the need for further research to elucidate associations between antihistamine prescriptions and seizure risk.

Total airway mechanics and fractional exhaled nitric oxide levels of children living in banjihas (semi-basements).

BACKGROUND: The ISAAC phase III study in Korea found a higher incidence of wheezing illnesses among residents in basements or semi-basements. OBJECTIVE: This study investigates the link between living in banjihas (semi-basements) and airway resistance and Th2 airway inflammation in Korean children, compared to those on higher floors. METHODS: We assessed 575 fifth- and sixth-grade students (aged 10-12) in an inner-city area of South Korea. The study utilized impulse oscillometry to measure small and total airway resistance (Rrs20-5 and Rrs0, respectively) and Fractional Exhaled Nitric Oxide (FeNO) measurements to evaluate airway inflammation. We also considered a range of biological and environmental factors, including allergen sensitization, serum 25-hydroxyvitamin D levels, and urinary metabolites like VOCs, bisphenol, and triclosan. Participants were categorized by living floors: banjihas, first-fifth floors, and sixth floors or higher. RESULTS: Twenty-five children (4.3%) lived in banjihas, 311 (54.1%) on the first to fifth floor, and 239 (41.6%) on the sixth floor or above. Despite similar levels of allergen sensitization and urinary pollutant metabolite levels across all groups, banjiha dwellers showed significantly higher total airway resistance (adjusted &1: 0.633, 95%CI: 0.156, 1.109; P = 0.009) and a greater prevalence of elevated FeNO levels (> 35 ppb) (P = 0.033). These findings persisted after adjusting for critical factors like height, gender, BMI z-score, and birth conditions. CONCLUSION: Children in banjihas exhibit elevated airway resistance and FeNO levels independently of allergen sensitization or pollution exposure, underscoring the necessity for enhanced focus on their respiratory health in such living conditions.

Association of fluoride exposure with disease burden and neurodevelopment outcomes in children in South Korea.

BACKGROUND: Community water fluoridation is an effective public health strategy for preventing dental caries, yet. Concerns exist about potential health problems. This study explores associations between tap water fluoride levels and pediatric disease burden, as well as neurodevelopmental outcomes at 6 years of age. METHODS: This nationwide population-based cohort study included children born in Korean cities with and without tap water fluoridation projects, between 2006 and 2012, aiming for a fluoride concentration of 0.8 ± 0.2 mg/L in treated tap water. Data from the National Health Insurance Service were used, spanning from birth to 2018. The relationship between exposure to fluoridated tap water and incidence of 16 childhood diseases that were previously identified as potentially linked to fluoride exposure were examined. Additionally, we evaluated the neurodevelopmental outcomes across various domains, including gross motor, fine motor, cognition, language, social skills, and self-help functions. These assessments were performed using data from a comprehensive national health screening program for children aged six years. RESULTS: A fluoride-unexposed group included 22,881 children, whereas a fluoride-exposed group comprised 29,991 children (52% males). Children in the fluoride-exposed group had a decreased risk of dental caries and bone fractures [hazard ratio (95% confidence interval, CI), 0.76 (0.63-0.93) and 0.89 (0.82-0.93), respectively] and increased risk of hepatic failures [1.85, (1.14-2.98)] compared to those in the unexposed group. Additionally, the risk ratio of abnormal neurodevelopmental screening outcomes increased by 9%, but this was statistically uncertain (95% CI, 0.95-1.26). CONCLUSIONS: Fluoridated tap water was associated with an increased risk of hepatic failure but a decreased risk of bone fractures in children. The association between fluoridated tap water and neurodevelopmental screening outcomes at 6 years remains unclear, highlighting the need for further studies to clarify this association.

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.

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.

Population-based retrospective cohort study on community-acquired pneumonia hospitalization in children with a ventricular septal defect.

The cohort consisted of 9400 exposed children diagnosed with ventricular septal defect (VSD). The risk of community-acquired pneumonia (CAP) or asthma with VSD was assessed using the Cox proportional hazard model with an inverse probability of treatment weighting. During a mean follow-up of 6.67 years (starting from 12 months after birth), there were 2100 CAP admission cases among exposed patients (incidence rate: 33.2 per 1000 person-years) and 20,109 CAP admission cases among unexposed children (incidence rate: 29.6 per 1000 person-years), with hazard ration of 1.09 (95% CI 1.04-1.14).

Rotavirus hospitalization in early childhood: fine motor skills and cognition at six years old-Population-based cohort study.

Rotavirus is linked to severe childhood gastroenteritis and neurological complications, but its impact on neurodevelopment remains uncertain. We examined data from 1,420,941 Korean children born between 2009 and 2011, using the Korean National Health Insurance System. At age 6, we assessed neurodevelopmental outcomes using the validated Korean Developmental Test, covering six major domains. Utilizing propensity score-based Inverse Probability Weighting to ensure covariates including considering covariates including sex, birth weight, changes in body weight from birth to 4-6 months of age, head circumference at 4-6 months of age, residence at birth, economic status, infant feeding types, and birth year. The main analysis that encompassed 5,451 children with rotavirus hospitalization and 310,874 unexposed individuals reveled heightened odds of suspected delays in fine motor skills and cognition among exposed children. Our results suggest an association between rotavirus-related hospitalization in infancy and suspected delays in fine motor function and cognition in 6-year-olds.

Trends in Incidence and Drug Prescriptions for Croup in Children Under 5 Years of Age: A 2002-2019 Population-Based Study.

BACKGROUND: Tracking national croup trends can provide important insights for childhood health management. This study aimed to analyze the incidence and drug prescription trends in Korean children over a two-decade period. METHODS: This population-based study encompassed 479,783 children aged < 5 years from 2002-2019, utilizing the National Health Insurance Service-National Sample Cohort. We identified participants with a primary croup diagnosis who were admitted to or visited the emergency room. Age-specific and age-adjusted incidence rates/10,000 person-years were calculated. We assessed using orthogonal polynomial contrasts and stratified by various factors (sex, age, residential area, economic status, comorbidities, and healthcare facility types). We observed changes in the use of five medications: inhaled steroids, systemic steroids, inhaled epinephrine, antibiotics, and short-acting bronchodilators. Generalized binomial logistic regression was used to analyze factors influencing prescription strategies. RESULTS: In 2002, the croup-related visits were 16.1/10,000 person-years, increasing to 98.3 in 2019 (P for trend < 0.001). This trend persisted, regardless of age, sex, region, and economic status. Children with comorbid atopic dermatitis or asthma maintained consistent croup rates, while those without comorbidities increased. Treatment trends showed decreasing antibiotic (73-47%) and oxygen use (21.3-3.4%), with increasing nebulized epinephrine (9.3-41.5%) and multiple drug prescriptions (67.8-80.3%). Primary care centers exhibited a greater increase in prescription usage and hospitalization duration than did tertiary healthcare institutions. CONCLUSION: Over the past two decades, croup incidence has risen, accompanied by increased epinephrine use and decreased antibiotic prescriptions. Longer hospitalization and higher medication use were mainly observed in primary care facilities.

Unraveling the link between atopic dermatitis and autoimmune diseases in children: Insights from a large-scale cohort study with 15-year follow-up and shared gene ontology analysis.

BACKGROUND: Atopic dermatitis and autoimmune diseases are highly heritable conditions that may co-occur from an early age. METHODS: The primary study is a national administrative cohort study involving 499,428 children born in 2002, tracked until 2017. Atopic dermatitis was defined as five or more principal diagnoses of atopic dermatitis and two or more topical steroid prescriptions. We estimated the risks for the occurrence of 41 autoimmune diseases, controlling for risk factors. In addition, we sourced a gene library from the National Library of Medicine to conduct a comprehensive gene ontology. We used Gene Weaver to identify gene set similarity and clustering, and used GeneMania to generate a network for shared genes. RESULTS: Exposed and unexposed groups included 39,832 and 159,328 children, respectively. During a mean follow-up of 12 years, the exposed group had an increased risk of autoimmune disease (hazard ratio, 1.27 [95 % confidence interval, 1.23-1.32]) compared to the unexposed group. The hazard ratios of autoimmune illnesses consistently increased with two- and five years lag times and alternative atopic dermatitis definitions. Shared genes between atopic dermatitis and autoimmune diseases were associated with comorbidities such as asthma, bronchiolitis, and specific infections. Genetic interactions of these shared genes revealed clustering in Th1, Th2, Th17, and non-classifiable pathways. CONCLUSIONS: Atopic dermatitis was significantly associated with an increased risk of subsequent autoimmune disease. we identified the genetically associated disease in atopic dermatitis patients comorbid with autoimmune disease and demonstrated a genetic network between atopic dermatitis and autoimmune diseases.

The KAAACI Guidelines for Sublingual Immunotherapy.

Allergen immunotherapy is regarded as the only disease-modifying treatment option for various allergic conditions, including allergic rhinitis and asthma. Among the routes of administration of allergens, sublingual immunotherapy (SLIT) has gained clinical interest recently, and the prescription of SLIT is increasing among patients with allergies. After 30 years of SLIT use, numerous pieces of evidence supporting its efficacy, safety, and mechanism allows SLIT to be considered as an alternative option to subcutaneous immunotherapy. Based on the progressive development of SLIT, the current guideline from the Korean Academy of Asthma, Allergy, and Clinical Immunology aims to provide an expert opinion by allergy, pediatrics, and otorhinolaryngology specialists with an extensive literature review. This guideline addresses the use of SLIT, including 1) mechanisms of action, 2) appropriate patient selection for SLIT, 3) the currently available SLIT products in Korea, and 4) updated information on its efficacy and safety. This guideline will facilitate a better understanding of practical considerations for SLIT.

Associations of personal urinary volatile organic compounds and lung function in children.

BACKGROUND: We investigated the correlation between urine VOC metabolites and airway function in children exposed to anthropogenic volatile organic compounds (VOCs), notable pollutants impacting respiratory health. METHODS: Out of 157 respondents, 141 completed skin prick tests, spirometry, IOS, and provided urine samples following the International Study of Asthma and Allergies in Childhood (ISAAC)-related questions. Allergic sensitization was assessed through skin prick tests, and airway functions were evaluated using spirometry and impulse oscillometry (IOS). Forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC) was recorded and FEV1/FVC ratio was calculated. Airway mechanics parameters including respiratory resistance at 5 Hz (Rrs5) mean respiratory resistance between 5 Hz and 20 Hz (Rrs5-20), were also recorded. Urine concentrations of metabolites of benzene, ethylbenzene, toluene, xylene, styrene, formaldehyde, carbon-disulfide were analyzed by gas chromatography/tandem mass spectroscopy. RESULTS: The median age at study participation was 7.1 (SD 0.3) years. Muconic acid (benzene metabolites) and o-methyl-hippuric acid (xylene metabolites) above medians were associated with a significant increase in Rrs5 (muconic acid: aß = 0.150, p = .002; o-methyl-hippuric acid: aß = 0.143, p = .023) and a decrease in FEV1/FVC (o-methyl-hippuric acid: aß = 0.054, p = .028) compared to those below median. No associations were observed for Rrs5-20 and FEV1 between the groups categorized as above and below the median (all parameter p values > .05). CONCLUSIONS: Elevated levels of benzene and xylene metabolites were associated with a significant increase in Rrs5 and a decrease in FEV1/FVC, related to increased resistance and restrictive lung conditions compared to individuals with concentrations below the median.

The association between phthalate exposure and pubertal development.

Antiandrogenic effect of phthalates have been reported; however, results regarding the effect of phthalate exposure in pubertal children have been inconsistent. We aimed to investigate the relationship between phthalate exposure and pubertal development, especially whether high molecular weight phthalates (HMWP) and low molecular weight phthalates (LMWP) are differently associated in boys and girls. Urinary phthalate metabolites (4 HMWPs and 3 LMWPs) in Korean children (236 boys and 202 girls, aged 10 to 12 years) were measured. The association between phthalate levels and pubertal development (pubertal stages self-reported by parents and sex steroid levels) was analyzed by generalized linear regression after adjusting for age, body mass index z score, and premature birth and/or low birth weight. Both the highest quartile of HMWP (Q4 vs Q1, adjusted odds ratio [OR], 0.238; 95% confidence interval [CI], 0.090-0.627; p = 0.004) and LMWP (Q4 vs Q1, adjusted OR, 0.373; 95% CI, 0.151-0.918; p = 0.032) were inversely associated with pubertal stages in boys, whereas the highest quartile of LMWP (Q4 vs Q1, adjusted OR, 2.431; 95% CI, 1.024-5.768; p = 0.044) was significantly related to advanced pubertal stages in girls. Testosterone levels in boys were significantly lower at the highest quartile of HMWP (adjusted ß = - 0.251; 95% CI, - 0.476 to - 0.027; p = 0.028). However, in girls, we could not find any significant relationship between HMWP or LMWP and estradiol levels. CONCLUSIONS: Our results suggest that phthalate exposure, especially exposure to the HMWP, may have inverse association with male pubertal development. Further investigation is required to verify the relationship of phthalate exposure and pubertal development in girls. WHAT IS KNOWN: • Exposure to phthalates may have antiandrogenic effects. • Studies on the association between phthalates and pubertal development have yielded inconsistent results. WHAT IS NEW: • Phthalate levels were inversely associated with self-reported pubertal stages in boys. • Exposure to phthalates might have a negative influence on male pubertal development.

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.

Cascade of atopic dermatitis comorbidities in children after birth for 15 years.

BACKGROUND: Individuals with atopic dermatitis often develop other conditions. OBJECTIVE: This study aimed to determine how atopic dermatitis comorbidities develop in children over time. METHODS: This population-based administrative cohort study used national health insurance data. We traced individuals born in Korea between 2002 and 2003 to 2018. The date of initial atopic dermatitis diagnosis was set as the index date. Fifty-three childhood comorbidities of atopic dermatitis were identified as outcomes of interest by performing a comprehensive literature search and comparing the prevalence of diagnostic codes in children with and without atopic dermatitis. Four control children per individual in the atopic dermatitis group were randomly matched based on sex and index date. The association between atopic dermatitis and the development of each specified disease was assessed using proportional hazard assumption, followed by mapping of the temporal sequences of interconnected comorbidities. RESULTS: The atopic dermatitis and control groups contained 67,632 and 270,528 individuals, respectively. The median age at the index date was 10 months, whereas the median follow-up period was 15 years. Twenty diseases that were associated with a higher risk of atopic dermatitis were identified and a chain of interconnected conditions created. The progression began in childhood with febrile seizures, constipation, and asthma, and was later associated with the emergence of food allergy, allergic rhinitis, psychiatric disorders, and autoimmune diseases. CONCLUSION: Our study highlights the temporal nature of atopic dermatitis comorbidities in children, and indicates that an understanding of the comorbidities may inform its clinical management and treatment.

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.

KAAACI Guidelines for Allergen Immunotherapy.

Allergen immunotherapy (AIT) is a causative treatment for various allergic diseases such as allergic rhinitis, allergic asthma, and bee venom allergy that induces tolerance to offending allergens. The need for uniform practice guidelines in AIT is continuously growing because of the increasing discovery of potential candidates for AIT and evolving interest in new therapeutic approaches. This guideline is an updated version of the Korean Academy of Asthma Allergy and Clinical Immunology recommendations for AIT published in 2010. This updated guideline proposes an expert opinion by allergy, pediatrics, and otorhinolaryngology specialists with an extensive literature review. The guideline deals with basic knowledge and methodological aspects of AIT, including mechanisms, clinical efficacy, patient selection, allergens extract selection, schedule and doses, management of adverse reactions, efficacy measurements, and special consideration in pediatrics. The guidelines for sublingual immunotherapy will be covered in detail in a separate article.

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.