Actionable pharmacogenetic variants in Hong Kong Chinese exome sequencing data and projected prescription impact in the Hong Kong population.

Preemptive pharmacogenetic testing has the potential to improve drug dosing by providing point-of-care patient genotype information. Nonetheless, its implementation in the Chinese population is limited by the lack of population-wide data. In this study, secondary analysis of exome sequencing data was conducted to study pharmacogenomics in 1116 Hong Kong Chinese. We aimed to identify the spectrum of actionable pharmacogenetic variants and rare, predicted deleterious variants that are potentially actionable in Hong Kong Chinese, and to estimate the proportion of dispensed drugs that may potentially benefit from genotype-guided prescription. The projected preemptive pharmacogenetic testing prescription impact was evaluated based on the patient prescription data of the public healthcare system in 2019, serving 7.5 million people. Twenty-nine actionable pharmacogenetic variants/ alleles were identified in our cohort. Nearly all (99.6%) subjects carried at least one actionable pharmacogenetic variant, whereas 93.5% of subjects harbored at least one rare deleterious pharmacogenetic variant. Based on the prescription data in 2019, 13.4% of the Hong Kong population was prescribed with drugs with pharmacogenetic clinical practice guideline recommendations. The total expenditure on actionable drugs was 33,520,000 USD, and it was estimated that 8,219,000 USD (24.5%) worth of drugs were prescribed to patients with an implicated actionable phenotype. Secondary use of exome sequencing data for pharmacogenetic analysis is feasible, and preemptive pharmacogenetic testing has the potential to support prescription decisions in the Hong Kong Chinese population.

Preterm postnatal complications and risk of attention-deficit/hyperactivity disorder.

AIM: To investigate the association between the risk of attention-deficit/hyperactivity disorder (ADHD) and preterm birth and determine how postnatal complications in children born preterm is associated with the risk of ADHD. METHOD: This population-based cohort study used data from the Hong Kong electronic medical records. We followed 359 614 children (48% female; 6-17 years old, mean 11 years 7 months, SD 3 years 2 months) born in public hospitals in Hong Kong from 1st January 2004 to 31st December 2014 and collected medical records and demographic details for mothers and children until 11th November 2020. RESULTS: The risk of ADHD was 4.0% in children born at term and 5.1% in children born preterm. The odds ratio for ADHD was 2.08 (95% confidence interval [CI] 1.64-2.64) for children born extremely preterm, 1.64 (95% CI 1.46-1.85) for children born very preterm, and 1.15 (95% CI 1.08-1.23) for children born late preterm. Among preterm postnatal complications, only early respiratory disease, retinopathy of prematurity (ROP), and intraventricular haemorrhage were significant predictors of ADHD after controlling for preterm birth, other risk factors, and sociodemographic variables. The excess risk of ADHD among children born very preterm or late preterm could be partly explained by respiratory disease. ROP partially mediated the risk of ADHD in children born very preterm. INTERPRETATION: Children born preterm in all subcategories, from extremely preterm to late preterm, have increased risk of ADHD. Early respiratory infection partially mediates the risk of ADHD in children born preterm.

Evaluating the Health-Related Quality of Life of the Rare Disease Population in Hong Kong Using EQ-5D 3-Level.

OBJECTIVES: This study aimed to establish a normative profile of health-related quality of life (HRQOL) of the rare disease (RD) population in Hong Kong (HK) and identify potential predictors. METHODS: Between March 2020 and October 2020, patients with RD and caregivers were recruited through Rare Disease Hong Kong, the largest RD patient group alliance in HK. HRQOL was derived using the EQ-5D 3-Level with reference to the established HK value set. Utility scores were stratified according to demographics and disease-related information. Multiple linear regression was performed to explore the associations between patient characteristics and HRQOL. RESULTS: A total of 286 patients, covering 107 unique RDs, reported a mean utility score of 0.53 (SD 0.36). Thirty patients (10.5%) reported negative utility scores, indicating worse-than-death health states. More problems were recorded in the "usual activities" and "self-care" dimensions. Univariate analyses revealed that neurologic diseases, high out-of-pocket expenditure, home modification, and living in public housing or subdivided flats/units were significantly associated with lower HRQOL. A total of 99 caregivers reported a mean utility score of 0.78 (SD 0.17), which was significantly associated with the utility score of patients they took care of (r = 0.32; P = .001). CONCLUSIONS: The normative profile of the RD population was established, which revealed lower HRQOL in the RD population than other chronic disease groups and general population in HK. Findings were corroborated by evidence from other cohorts using EQ-5D, combined as part of a meta-analysis. Identifying predictors highlight areas that should be prioritized to improve HRQOL of RD population through clinical and psychosocial dimensions.

Actionable secondary findings in 1116 Hong Kong Chinese based on exome sequencing data.

The use of exome and genome sequencing has increased rapidly nowadays. After primary analysis, further analysis can be performed to identify secondary findings that offer medical benefit for patient care. Multiple studies have been performed to evaluate secondary findings in different ethnicities. However, relevant data are limited in Chinese. Here, with the use of a cohort consisted of 1116 Hong Kong Chinese exome sequencing data, we evaluated the secondary findings in the 59 genes recommended by the American College of Medical Genetics and Genomics. Fifteen unique pathogenic or likely pathogenic variants in 17 individuals were identified, representing a frequency of 1.52% in our cohort. Although 20 individuals harboured pathogenic or likely pathogenic variants in recessive conditions, none carried bi-allelic mutations in the same gene. Our finding was in accordance with the estimation from the American College of Medical Genetics and Genomics that about 1% individuals harbour secondary findings.

Functional analysis and evaluation of respiratory cilia in healthy Chinese children.

BACKGROUND: To aid in the diagnosis of Primary Ciliary Dyskinesia (PCD) and to evaluate the respiratory epithelium in respiratory disease, normal age-related reference ranges are needed for ciliary beat frequency (CBF), beat pattern and ultrastructure. Our aim was to establish reference ranges for healthy Chinese children. METHODS: Ciliated epithelial samples were obtained from 135 healthy Chinese children aged below 18 years by brushing the inferior nasal turbinate. CBF and beat pattern were analysed from high speed video recordings. Epithelial integrity and ciliary ultrastructure were assessed using transmission electronic microscopy. RESULTS: The mean CBF from 135 children studied was 10.1 Hz (95% CI 9.8 to 10.4). Approximately 20% (ranged 18.0-24.2%) of ciliated epithelial edges were found to have areas of dyskinetically beating cilia. Normal beat pattern was observed in ciliated epithelium from all subjects. We did not find any effect of exposure to second hand smoke on CBF in our subjects. Microtubular defects were found in 9.3% of all of the cilia counted in these children, while other ciliary ultrastructural defects were found in less than 3%. CONCLUSIONS: We established the reference range for CBF, beat pattern and ultrastructure in healthy Chinese children. Using similar methodology, we found a lower overall mean CBF than previously obtained European values. This study highlights the need to establish normative data for ciliary function in different populations.

Paternal uniparental disomy of chromosome 19 in a pair of monochorionic diamniotic twins with dysmorphic features and developmental delay.

BACKGROUND: We report here clinical, cytogenetic and molecular data for a pair of monochorionic diamniotic twins with paternal isodisomy for chromosome 19. Both twins presented with dysmorphic features and global developmental delay. This represents, to our knowledge, the first individual human case of paternal uniparental disomy for chromosome 19 (UPD19). METHODS: Whole-exome sequencing, together with conventional karyotype and SNP array analysis were performed along with genome-wide DNA methylation array for delineation of the underlying molecular defects. RESULTS: Conventional karyotyping on amniocytes and lymphocytes showed normal karyotypes for both twins. Whole-exome sequencing did not identify any pathogenic sequence variants but >5000 homozygous exonic variants on chromosome 19, suggestive of UPD19. SNP arrays on blood and buccal DNA both showed paternal isodisomy for chromosome 19. Losses of imprinting for known imprinted genes on chromosome 19 were identified, including ZNF331, PEG3, ZIM2 and MIMT1. In addition, imprinting defects were also identified in genes located on other chromosomes, including GPR1-AS, JAKMP1 and NHP2L1. CONCLUSION: Imprinting defects are the most likely cause for the dysmorphism and developmental delay in this first report of monozygotic twins with UPD19. However, epigenotype-phenotype correlation will require identification of additional individuals with UPD19 and further molecular analysis.

The association of breastfeeding with insulin resistance at 17 years: Prospective observations from Hong Kong's "Children of 1997" birth cohort.

Breastfeeding has many benefits for mother and infant. Whether breastfeeding also protects against type 2 diabetes is unclear. To clarify the role of breastfeeding in type 2 diabetes, we assessed the association of breastfeeding with insulin resistance in late adolescence in a birth cohort from a non-Western setting where breastfeeding was not associated with higher socio-economic position. We used multivariable linear regression, with multiple imputation and inverse probability weighting, to examine the adjusted associations of contemporaneously reported feeding in the first 3 months of life (exclusively breastfed, mixed feeding, or always formula-fed) with fasting glucose, fasting insulin, and homeostasis model assessment of insulin resistance (HOMA-IR) at 17 years in a subset (n = 710, 8.6% of entire cohort) of the Hong Kong Chinese birth cohort "Children of 1997." We found a graded association of breastfeeding exclusivity in the first 3 months of life with lower fasting insulin and HOMA-IR (p-for-trend < .05), but not fasting glucose, at 17 years. Exclusively breastfed adolescents (7%) had nonsignificantly lowest fasting insulin and HOMA-IR, adjusted for sex, birth weight, parity, length of gestation, pregnancy characteristics, parents' education, and mother's place of birth. Exclusively breastfeeding for 3 months may be causally associated with lower insulin resistance in late adolescence. Further follow-up studies into adulthood are required to clarify the long-term protection of breastfeeding from type 2 diabetes.

Childhood Obesity and Physical Activity-Friendly School Environments.

OBJECTIVE: Childhood obesity may be related to school environment, but previous studies often focused on food environment only. This study aimed to examine the relationship between school physical activity environment and childhood obesity. STUDY DESIGN: This is a cross-sectional study with multilevel data collected on school physical activity environment using teacher questionnaires, students' growth, and obesity status from electronic health records, and neighborhood socioeconomic status from census data. RESULTS: This study included 208 280 students (6-18 years of age) from 438 schools (45% of Hong Kong). Prevalence of obesity was 5.0%. After controlling for socioeconomic status and intraschool correlation, robust Poisson regression revealed a reduced obesity risk associated with higher teachers' perceived physical activity benefits (risk ratio 0.96, 95% CI 0.94-0.99, P = .02), physical activity teaching experience (0.93, 0.91-0.96, P < .001), school campus size (0.93, 0.87-0.99, P = .02), physical activity ethos (0.91, 0.88-0.94, P < .001), number of physical activity programs (0.93, 0.90-0.96, P < .001), and physical activity facilities (0.87, 0.84-0.90, P < .001). Students in schools with at least 3 physical activity-friendly environmental factors (11.7%) had a much lower risk of obesity (0.68, 0.62-0.75, P < .001) than those without (23.7%). CONCLUSIONS: A physical activity-friendly school environment is associated with lower risk of obesity. School physical activity environment should be considered in future epidemiologic and intervention studies.

Prenatal Tobacco Exposure Shortens Telomere Length in Children.

INTRODUCTION: Preliminary evidence suggests a possible association between prenatal tobacco exposure and telomere length in children. This study was conducted to investigate whether maternal smoking during pregnancy was associated with telomere shortening in their children and whether prenatal and childhood exposure to environmental tobacco had any impact on this association. METHODS: This is a population-representative study on the association between prenatal tobacco exposure and telomere length in children. Ninety-eight Hong Kong Chinese children aged under 15 years with prenatal tobacco exposure and 98 age- and gender-matched controls were recruited from a population health study with stratified random sampling. RESULTS: Telomere length in children with prenatal tobacco exposure was significantly shorter than in those with no exposure (mean T/S ratio = 24.9 [SD = 8.58] in exposed vs. 28.97 [14.15] in control groups; P = 0.02). A negative dose-response relationship was observed between the T/S ratio and tobacco exposure duration: the longer the duration of maternal smoking in pregnancy, the shorter the child's telomere length. The association between the child's telomere length and prenatal tobacco exposure remained significant after considering the influence of family socioeconomic status and exposure to environmental tobacco smoke during pregnancy and childhood. CONCLUSIONS: Prenatal tobacco exposure was associated with telomere shortening in children. As this may impose significant health impacts through fetal genetic programming, more efforts should be made to reduce fetal tobacco exposure by educating pregnant women to not smoke and motivating smokers to quit in early pregnancy. IMPLICATIONS: As reflected by telomere shortening, prenatal tobacco exposure in children can cause premature aging and increased health risks, which we suggest is entirely preventable. Not smoking during pregnancy or quitting smoking is critical to improving the health outcome of our future generations as prenatal tobacco exposure may affect children's biological programming.

Sleep Duration and School Readiness of Chinese Preschool Children.

OBJECTIVES: To examine the average sleep duration in Chinese preschoolers and to investigate the association between sleep duration and school readiness. STUDY DESIGN: This is a cross-sectional study that included 553 Chinese children (mean age = 5.46 years) from 20 preschools in 2 districts of Hong Kong. Average daily sleep duration in the last week was reported by parents and school readiness as measured by the teacher-rated Chinese Early Development Instrument (CEDI). RESULTS: Most Chinese preschoolers had 9-10 hours of sleep per day. Only 11% of preschoolers had the recommended 11-12 hours of sleep per day. This group was associated with more "very ready" CEDI domains. Sleep deprivation (≤7 hours per day) was associated with a lower CEDI total score, lower scores in the emotional maturity and language/cognitive domain, and prosocial behaviors subdomain but a greater score in the hyperactivity/inattention subdomain. Children with a lower family socioeconomic index, lower maternal education level, infrequent parent-child interactions, and who used electronic devices for more than 3 hours per day had shortened sleep durations. CONCLUSIONS: Optimal sleep duration was associated with better school readiness in preschool children, whereas sleep deprivation was associated with lower school readiness, more hyperactivity and inattention, and less prosocial behavior.

Smoke-free legislation reduces hospital admissions for childhood lower respiratory tract infection.

BACKGROUND: Previous studies showed reduction of hospital admissions for asthma after implementation of comprehensive smoke-free legislation. We aimed to evaluate the impact of comprehensive smoke-free legislation implemented in Hong Kong in 2007 on hospital admissions for childhood lower respiratory tract infection (LRTI). METHODS: We obtained data on 75 870 hospital admissions for LRTI among children ≤18 years of age between January 2004 and December 2012 from all Hospital Authority hospitals. Using a negative binomial regression model, we assessed the impact of smoke-free legislation on admission counts. RESULTS: After legislation implementation, there was an immediate effect with a change in the admission count of -33.5% (95% CI -36.4% to -30.5%), and a change in time trend to -13.9% per year (95% CI -16.0% to -11.7%). Overall, the legislation was associated with a net 47.4% reduction in admission counts in the first year. We estimated that the legislation was associated with a reduction of 13 635 admissions in the first 6 years after implementation. The immediate reduction and change in time trend was more apparent among school-age than preschool children. CONCLUSIONS: Implementation of comprehensive smoke-free legislation was associated with a significant reduction in hospital admissions for childhood LRTI.

Adenovirus respiratory infection in hospitalized children in Hong Kong: serotype-clinical syndrome association and risk factors for lower respiratory tract infection.

Lower respiratory tract infections (LRTI) caused by adenovirus can be severe with resultant chronic pulmonary sequelae. More than 50 serotypes have been recognized; however, the exact association of serotype with clinical phenotype is still unclear. There have been no reports on the adenovirus serotype pattern in Hong Kong, and their relationships with disease manifestations and complications are not known. Clinical and epidemiological data on 287 children (<6 years old) admitted with adenovirus respiratory infections from 2001 to 2004 were reviewed. Common presenting symptoms included fever (97.9 %) and cough and rhinitis (74 %). Extra-pulmonary manifestations were present in 37.3 %. The clinical picture mimicked bacterial infection for its prolonged high fever and neutrophilic blood picture. Forty-two patients (14.6 %) had LRTI, either pneumonia or acute bronchiolitis, but none had severe acute respiratory compromise. Children aged 1 to 2 years old were most at risk for adenovirus LRTI (adjusted p = 0.0165). Serotypes 1 to 7 could be identified in 93.7 % of the nasopharyngeal specimens, with serotypes 2 and 3 being the most prevalent. Different serotypes showed predilection for different age groups and with different respiratory illness association. The majority of acute bronchiolitis (71.4 %) were associated with serotype 2 infection, and this association was statistically significant (p < 0.0001). Serotype 3 infection accounted for over half of the pneumonia cases (57-75 %) in those aged 3-5 years old. Only one patient developed mild bronchiectasis after serotype 7 pneumonia. Children aged 1 to 2 years old were the at-risk group for adenovirus LRTI, but respiratory morbidity was relatively mild in our locality. There was an apparent serotype-respiratory illness association.

Telehealth-delivered parent-based sleep-focused intervention for insomnia in preschool children with autism spectrum disorder: A randomized controlled study.

LAY ABSTRACT: Sleep problems are common in children with autism spectrum disorder. Although the effects of parent-based sleep intervention were shown to be promising, previous research was limited to the face-to-face service model, which might limit accessibility. This study examined a sleep-focused parent training group delivered via telehealth for treating insomnia in preschool children with autism spectrum disorder, which allowed parents to join the intervention remotely. Results showed that children in the intervention group had greater improvements in sleep and insomnia symptoms after treatment, as compared to those who only received care as usual. This sleep-focused treatment also led to improved daytime behaviors, especially externalizing problems such as hyperactivity and conduct problems, in children with autism spectrum disorder. Parents who had attended the training also reported reduced parental stress level after treatment. The findings supported the feasibility and promising effects of a brief parent-based sleep intervention delivered via telehealth for preschooler with autism spectrum disorder.

Influenza vaccine effectiveness against hospitalizations associated with influenza A(H3N2) in Hong Kong children aged 9 months to 17 years, June-November 2023.

A test negative study was carried out from 13 June through to 15 November 2023 enrolling 3183 children hospitalized with acute respiratory illness in Hong Kong. Influenza A and B viruses were detected in 528 (16.6%) children, among which 419 (79.4%) were influenza A(H3N2). The overall vaccine effectiveness against hospitalization associated with any influenza virus infection was estimated as 22.4% (95% CI: -11.7%, 46.1%), and against influenza A(H3N2) specifically was 14.3% (95% CI: -29.2%, 43.2%). Despite the moderate to low VE estimated here, which could be a result of waning immunity and antigenic drift, influenza vaccination remains an important approach to reduce the impact of influenza in children.

Expanded Prader-Willi syndrome due to chromosome 15q11.2-14 deletion: report and a review of literature.

We report on a male infant with de novo unbalanced t(5;15) translocation resulting in a 17.23 Mb deletion within 15q11.2-q14 and a 25.12 kb deletion in 5pter. The 15q11.2-q14 deletion encompassed the 15q11.2-q13 Prader-Willi syndrome (PWS) critical region and the recently described 15q13.3 microdeletion syndrome region while the 5pter deletion contained no RefSeq genes. From our literature review, patients with similar deletions in chromosome 15q exhibit expanded phenotype of severe developmental delay, protracted feeding problem, absent speech, central visual impairment, congenital malformations and epilepsy in addition to those typical of PWS. The patient reported herein had previously unreported anomalies of mega cisterna magna, horseshoe kidney and the rare neonatal interstitial lung disease known as pulmonary interstitial glycogenosis. Precise breakpoint delineation by microarray is useful in patients with atypical PWS deletions to guide investigation and prognostication.

Successful use of BiPAP in infants with congenital myotonic dystrophy.

Reported herein are two cases of severe phenotype of congenital myotonic dystrophy (CDM) with presentation of respiratory insufficiency at birth. The infants were successfully managed with bi-level positive airway pressure (BiPAP) via nasal mask. The use of BiPAP in infants with CDM has not been reported before. The rationale for using BiPAP is discussed. BiPAP may be more effective than continuous positive airway pressure in managing respiratory insufficiency, especially in infants with the more severe phenotype of CDM.

Socio-economic costs of rare diseases and the risk of financial hardship: a cross-sectional study.

Background: To achieve universal healthcare coverage (UHC), the rare disease (RD) population must also receive quality healthcare without financial hardship. This study evaluates the impact of RDs in Hong Kong (HK) by estimating cost from a societal perspective and investigating related risk of financial hardship. Methods: A total of 284 RD patients and caregivers covering 106 RDs were recruited through HK's largest RD patient group, Rare Disease Hong Kong, in 2020. Resource use data were collected using the Client Service Receipt Inventory for Rare disease population (CSRI-Ra). Costs were estimated using a prevalence-based, bottom-up approach. Risk of financial hardship was estimated using catastrophic health expenditure (CHE) and impoverishing health expenditure (IHE) indicators. Multivariate regression was performed to identify potential determinants. Findings: Annual total RD costs in HK were estimated at HK$484,256/patient (United States (US) $62,084). Direct non-healthcare cost (HK$193,555/US$24,814) was the highest cost type, followed by direct healthcare (HK$187,166/US$23,995), and indirect (HK$103,535/US$13,273) costs. CHE at the 10% threshold was estimated at 36.3% and IHE at the $3.1 poverty line was 8.8%, both significantly higher than global estimates. Pediatric patients reported higher costs than adult patients (p < 0.001). Longer years since genetic diagnosis was the only factor significantly associated with both total costs (p = 0.026) and CHE (p = 0.003). Interpretation: This study serves as the first in the Asia Pacific region to simultaneously assess the societal costs and financial hardship related to RDs and highlights the importance of an early genetic diagnosis. These results contribute to existing evidence on the globally ubiquitous high costs of RDs, warranting collaboration between different stakeholders to include RD population in UHC planning. Funding: Health and Medical Research Fund, and the Society for the Relief of Disabled Children.

Influenza Vaccine Effectiveness Against Influenza-Associated Hospitalization in Hong Kong Children Aged 9 Months to 17 Years, March-June 2023.

In March-June 2023, we conducted a test-negative study in 1671 children who were hospitalized with acute respiratory illness in Hong Kong. Two hundred and eighty-six children (17.2%) were tested positive for influenza virus including 188 with A(H1N1). We estimated influenza vaccine effectiveness against influenza-associated hospitalization as 69.6% (95% confidence interval: 49.3%, 81.7%).

Mental Health of Children With Special Educational Needs and the Return to In-Person Learning After the COVID-19 Pandemic.

Importance: There is limited evidence on whether the quality of life and behavior of children with special educational needs (SEN) have improved or worsened since schools reopened after COVID-19-related school closures. Objective: To describe the changes in the mental well-being of children and adolescents with SEN during the initial 6 months of resuming in-person learning after COVID-19-related school closures. Design, Setting, and Participants: This repeated cross-sectional study reported data from surveys completed by parents and caregivers of children and adolescents aged 3 to 18 years with SEN studying at special schools in Hong Kong. The first cohort was obtained during COVID-19-related school closure in April 2020 (wave 1) and the second cohort was obtained 6 months after school resumption with data collection between July and October 2021 (wave 2). Data analysis occurred from January to June 2022. Exposure: Diagnosis of a disability or disorder that required school-based special educational programming. Main Outcomes and Measures: Children's emotional and behavioral difficulties (measured with the Strengths and Difficulties Questionnaire [SDQ]), quality of life (measured with the Pediatric Quality of Life Inventory [PedsQL]), lifestyle habits, parental stress, and parental well-being (measured with the PedsQL Family Impact Module) were assessed. Cross-sectional comparisons of well-being between the 2 waves were conducted using analysis of covariance, and multiple regression analysis was performed to identify factors associated with mental health outcomes in wave 2. Results: In wave 1, a total of 456 parents and caregivers of children with SEN (mean [SD] age, 7.44 [3.98] years; 315 boys [69.1%]; 141 girls [30.9%]) responded to the surveys. In wave 2, 519 parents and caregivers of children with SEN (mean [SD] age, 8.16 [4.47] years; 365 boys [70.3%]; 154 girls [29.7%]) responded. After school resumption, preschoolers aged 3 to 5 years with SEN had significantly fewer emotional difficulties (mean [SD] SDQ score, 3.26 [2.39] vs 2.68 [2.03]; standardized mean difference [SMD] = 0.26; 95% CI, 0.07-0.46; Bonferroni-corrected P = .04) and conduct difficulties (mean [SD] SDQ score, 2.88 [1.89] vs 2.41 [1.91]; SMD = 0.25; 95% CI, 0.05-0.44; Bonferroni-corrected P = .01), whereas adolescents had more conduct difficulties (mean [SD] SDQ score, 1.62 [1.50] vs 2.37 [3.02]; SMD = 0.41; 95% CI, 0.13-0.70; Bonferroni-corrected P = .049). The overall quality of life of school-aged children with SEN aged 6 to 11 years worsened after school resumption (mean [SD] PedsQL score, 67.52 [17.45] vs 60.57 [16.52]; SMD = 0.41; 95% CI, 0.19-0.62; Bonferroni-corrected P = .002). Conclusions and Relevance: The findings of this repeated cross-sectional study suggest that preschoolers with SEN had improved emotional and behavioral functioning when school resumed after COVID-19-related closures. School-aged children with SEN, adolescents with SEN, and children with intellectual disabilities were at risk of reduced quality of life, indicating that additional support should be offered to vulnerable groups as they return to schools.