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Aims: The association between a pregnant mother's vitamin D status and depressive symptoms has yielded inconsistent results. It is possible that other factors play a role in this association, as depression can have multiple causes. Recognizing the significance of the husband's participation in antenatal care, this study aimed to examine whether the husband's involvement moderates the link between the mother's vitamin D status and depressive symptoms during pregnancy., Methods: A total of 2983 Chinese married pregnant women, in their 25-35 weeks of pregnancy, completed questionnaires to assess their levels of depressive symptoms and the involvement of their husbands in their antenatal care appointments. Additionally, their serum levels of vitamin D were measured., Results: After adjusting for maternal age, parity, and socio-economic status, the husband's involvement in antenatal care moderated the association between maternal vitamin D status and depressive symptoms during pregnancy (β = 2.03, p  = 0.035). Specifically, when their husbands were not regularly present for antenatal care appointments, mothers with suboptimal vitamin D levels experienced more depressive symptoms than those with optimal levels. However, there were no noticeable differences in depressive symptoms between vitamin D groups for mothers whose husbands attended all antenatal care appointments., Conclusions: Pregnant women who have suboptimal vitamin D levels and lack support from their spouses are most vulnerable to experiencing depression. It is crucial to holistically assess the social and physiological needs of expectant mothers to reduce their risk of antenatal depression.

Limited research has been conducted to examine the factors during early childhood that may contribute to conduct problems in later stages of life. This study aimed to investigate the relationship between family and school environments during early childhood and conduct problems in adolescence. In Wave 1 (W1), the study recruited 502 participants, aged 5-6 years, from Hong Kong local kindergartens, with 51.4% boys. One of their parents provided information about family socioeconomic status (SES), parent-child recreational activities, and child screen time, whereas the class teacher rated their school readiness using the Chinese version of the Early Development Instrument. Data on the number of special facilities were obtained from the kindergartens. In Wave 2 (W2), the same parents of 395 participants were asked about their involvement in their children's education. Finally, in Wave 3 (W3), the parents of 206 participants completed the Conduct Problem scale of the Strength and Difficulties Questionnaire to evaluate the level of conduct problems in the participants. The results of the path analysis revealed that higher W1 family SES was associated with fewer W3 conduct problems through an increase in W1 and W2 parental involvement in children's learning and play activities. Findings have implications for understanding the impact of early-life family and school environments on adolescent conduct problems. Early childhood interventions that promote family resources and positive parent-child interactions have the potential to reduce adolescent conduct problems., (© 2024 The Author(s). Family Process published by Wiley Periodicals LLC on behalf of Family Process Institute.)

Background: Growing evidence indicates an association between disordered eating and a range of mental health problems, including anxiety, depression and emotional dysregulation., Aims: This study aimed to explore whether reducing risk factors for eating disorders, such as body dissatisfaction and low self-esteem, through school-based programmes can enhance adolescent mental health., Method: We searched PubMed, PsycINFO, EMBASE and Web of Science from the date of inception to 15 October 2023. Data were synthesised by using a systematic narrative synthesis framework, and formal assessments were conducted to assess the quality of the included studies., Results: After title/abstract screening and full-text assessment, 13 articles met the pre-specified inclusion criteria, comprising a total of 14 studies ( n = 5853). Notably, three studies encompassed multiple programmes, leading to the identification of 17 eating disorder prevention programmes. Among these programmes, seven (41%) employed dissonance-based approaches. Topics covered in the programmes included psychoeducation, body acceptance, sociocultural issues, nutrition and physical activities, self-esteem and stress coping. Ten (59%) of the programmes were effective in improving adolescent mental health. Six of the 14 studies (43%) did not specify follow-up time, and quality assessments found the majority to be of either high (five studies, 36%) or fair (eight studies, 57%) quality., Conclusions: The findings from the ten effective programmes consistently support the use of body acceptance strategies in improving the mental health of adolescent students. Brief interventions delivered by trained, non-licensed facilitators appear good for the sustainable implementation of in-school psychological services to support well-being among adolescents.

Objective: Not all women experience the same changes in depression from pregnancy through the years following childbirth, but the patterns of prenatal and postnatal depression are underexplored. This study investigated the trajectories and associated predictors of depressive symptoms in women from pregnancy through the first 3 years postpartum., Method: We followed 340 pregnant women from an antenatal clinic in Hong Kong, first at 20-24 weeks of gestation, then at 4 weeks after childbirth, and again at 3 years after childbirth. Pregnant women reported their depressive symptoms whether they had intimate partner violence, health conditions, adverse childhood experiences, family support, and perceived partner involvement. Latent class growth analysis was applied to identify distinct trajectories of depression, and binary logistic regressions were performed to analyze predictors of trajectories., Results: We found that 26.5% of women showed clinical depressive symptoms at 20-24 weeks of gestation, 9.7% at 4 weeks after childbirth, and 12.6% at 3 years after childbirth. Two classes were identified: a low-stable group (86.2%) and a relapsing/remitting group (13.8%). Women with a history of trauma (i.e., intimate partner violence and adverse childhood experiences) and mental health difficulties were more likely to be classified in the relapsing/remitting group than in the low-stable group. Family support and partner emotional involvement appeared to protect the women from suffering relapsing/remitting depression., Conclusions: The findings highlight the importance of screening for depression throughout pregnancy and extending several years postpartum. Distinguishing the different trajectories of depression and identifying its associated factors are critical to providing targeted interventions to the most vulnerable women (i.e., a relapsing/remitting group in the present study). (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Background: Reticulocyte haemoglobin equivalent (RET-He) is a useful tool for evaluating recent iron usage irrespective of inflammatory status. This study aims to establish a reference for RET-He among Hong Kong healthy children under the age of 5 years and to investigate the association between RET-He and various blood parameters., Methods: A total of 946 children aged 2-48 months from July 2019 to December 2022 were recruited in this cross-sectional study. The RET-He and other haematological parameters were measured by the haematology analyser from Sysmex XN-9100/XN-1500. The ferritin test was performed with the electrochemiluminescence immunoassay. Interval 2.5th percentile to 97.5th percentile represented the normal RET-He ranges. Linear multiple regression analysis was performed to examine the relation between RET-He and various blood parameters. Receiver-operating characteristic curve analysis revealed the sensitivity and specificity of RET-He in identifying iron deficiency., Results: The RET-He in the study population was approximately normally distributed. The age-specific lower limit of RET-He ranges from 25.81 pg (25-36 months) to 27.15 pg (13-24 months). RET-He was found to be lower in the age group 2-6 months (mean=29.47 pg) and 7-12 months (mean=29.41 pg). Changes in RET-He and haemoglobin in relation to age were observed in both sexes (both p<0.001). RET-He was influenced by age, some red blood cell parameters and reticulocyte concentrations (all p<0.05). A cut-off value of RET-He ≤27.8 pg was determined for identifying iron deficiency., Conclusions: RET-He levels varied with age, with a relatively lower level in infants than in other age groups. The value below the age-specific lower limit of the reference range of RET-He can be used as a limit for preliminary iron-deficiency screening., Competing Interests: Competing interests: none., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Obesity has become a global health concern in recent decades. Utilizing biomarkers presents a promising approach to comprehensively monitor the progress of obesity and its associated health conditions. This review aims to synthesize the available evidence on the correlation between cfDNA level and obesity and to provide insights into the applicability of using cfDNA level as a tool for monitoring progression of obesity. Searches were performed in PubMed and Embase on April 1, 2022. Data and other relevant information were extracted and compiled into a structured table for further analysis. Among 1170 articles screened, 11 articles were included in this review and assessed qualitatively. The results demonstrated that existing evidence mainly focused on three populations, including healthy individuals, cancer patients and pregnant women. Majority of the studies on healthy individuals identified a significant association between cfDNA level and body weight status but not among cancer patients. Varying results were observed among pregnant women at different gestational trimesters. Our review summarized some preliminary evidence on the association between cfDNA level and obesity. More cohort studies in larger scale with comprehensive assessment have to be conducted to examine the applicability of cfDNA as a biomarker for severity and disease progression of obesity., (© 2024 The Authors. Obesity Reviews published by John Wiley & Sons Ltd on behalf of World Obesity Federation.)

Background: Vaccine-related acute myocarditis is recognized as a rare and specific vaccine complication following mRNA-based COVID-19 vaccinations. The precise mechanisms remain unclear. We hypothesized that natural killer (NK) cells play a central role in its pathogenesis., Methods: Samples from 60 adolescents with vaccine-related myocarditis were analyzed, including pro-inflammatory cytokines, cardiac troponin T, genotyping, and immunophenotyping of the corresponding activation subsets of NK cells, monocytes, and T cells. Results were compared with samples from 10 vaccinated individuals without myocarditis and 10 healthy controls., Findings: Phenotypically, high levels of serum cytokines pivotal for NK cells, including interleukin-1β (IL-1β), interferon α2 (IFN-α2), IL-12, and IFN-γ, were observed in post-vaccination patients with myocarditis, who also had high percentage of CD57 + NK cells in blood, which in turn correlated positively with elevated levels of cardiac troponin T. Abundance of the CD57 + NK subset was particularly prominent in males and in those after the second dose of vaccination. Genotypically, killer cell immunoglobulin-like receptor (KIR) KIR2DL5B(-)/KIR2DS3(+)/KIR2DS5(-)/KIR2DS4del(+) was a risk haplotype, in addition to single-nucleotide polymorphisms related to the NK cell-specific expression quantitative trait loci DNAM-1 and FuT11, which also correlated with cardiac troponin T levels in post-vaccination patients with myocarditis., Conclusion: Collectively, these data suggest that NK cell activation by mRNA COVID-19 vaccine contributed to the pathogenesis of acute myocarditis in genetically and epidemiologically vulnerable subjects., Funding: This work was funded by the Hong Kong Collaborative Research Fund (CRF) 2020/21 and the CRF Coronavirus and Novel Infectious Diseases Research Exercises (reference no. C7149-20G)., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Objective: Research has documented the associations of child maltreatment with a range of physical health problems, but little is known about the physical growth patterns of children who experience maltreatment in early childhood. This study aimed to examine the association between various discipline approaches and physical growth in preschool-aged children., Methods: In the first year of preschool, parents of 661 Chinese preschool-aged children completed a questionnaire with items pertaining to the frequency of using physical maltreatment, psychological aggression, neglect, and nonviolent discipline toward the child. Children's weight and height were assessed annually using direct assessment in the first and two subsequent years. Longitudinal analyses were performed using multiple regression models., Results: More frequent neglect and psychological aggression during the first year of preschool were associated with a higher likelihood of a decreased BMI z score in subsequent years. Conversely, increased experience of physical maltreatment in the first year was associated with an increased likelihood of having overweight or obesity in the third year., Conclusions: Results indicate that early maltreatment experience can impact physical growth. This highlights the importance of preventing abusive parenting and encouraging healthy habits in young children who have experienced maltreatment to decrease their future risk for weight problems., (© 2024 The Authors. Obesity published by Wiley Periodicals LLC on behalf of The Obesity Society.)

This study aimed to establish sex- and age-specific reference values for motor performance (MP) in Hong Kong preschoolers aged 3-5 years old and examine the relationship between MP and BMI status. A cross-sectional study was conducted among 5579 preschoolers in Hong Kong. Three MP tests were administered, and height and weight information were collected. GAMLSS was used to compute the normative values of the motor tests. Boys outperformed girls in activities requiring muscle strength and power, while girls outperformed boys in activities requiring balance and coordination. The MP scores increased with age for both overarm beanbag throw and standing long jump for both sexes, while the one-leg balance scores showed larger differences between P 50 and P 95 in older preschoolers. Children with excessive weight performed worse in standing long jump and one-leg balance compared to their healthy weight peers. This study provides valuable information on the MP of preschoolers in Hong Kong, including sex- and age-specific reference values and the association between BMI status and MP scores. These findings can serve as a reference for future studies and clinical practice and highlight the importance of promoting motor skill development in preschoolers, particularly those who are overweight or obese., (© 2024. The Author(s).)

Hypovitaminosis D during infancy is associated with the development of chronic diseases and poor health later in life. While the effect of environmental factors on vitamin D concentration has been extensively explored, this study aimed to explore the effect of genetic factors on vitamin D concentration among Chinese infants. We conducted a multi-centre cross-sectional study in Hong Kong from July 2019 to May 2021. A candidate genetic approach was adopted to study four selected genetic variants of the vitamin D-binding protein (DBP) and vitamin D receptor (VDR) (rs4588, rs7041, rs2282679 and rs2228570) to examine their associations with measured serum 25(OH)D concentration. A total of 378 Chinese infants aged 2-12 months were recruited in this study. Peripheral blood samples were collected from the infants to measure serum 25(OH)D concentration and extract DNA. Results showed that rs7041T and rs2282679C were significantly associated with lower serum 25(OH)D concentration. Further analysis of the DBP variants revealed that the GC1F allele was significantly associated with lower 25(OH)D concentration and identified as the risk DBP isoform in infants. While our results revealed that there is no direct association between VDR-FokI genotype and serum 25(OH)D concentration, a VDR-FokI genotype-specific pattern was observed in the association between DBP isoforms and serum 25(OH)D concentration. Specifically, significant associations were observed in the DBP genotypes GC1F/F, GC1F/2 and GC1S/2 among VDR-FokI TT/TC carriers, but not in VDR-FokI CC carriers. Our findings lay down the basis for the potential of genetic screening to identify high risk of hypovitaminosis D in Chinese infants., (© 2023 The Authors. Nutrition Bulletin published by John Wiley & Sons Ltd on behalf of British Nutrition Foundation.)

Background: Evidence supports the effectiveness of serious games in health education, but little is known about their effects on the psychosocial well-being of children in the general population., Objective: This study aimed to investigate the potential of a mobile game-based safety education program in improving children's safety and psychosocial outcomes., Methods: Safe City is a mobile roleplaying game specifically designed to educate children in Hong Kong about safety. This randomized controlled trial included 340 children in grades 4 through 6. Intervention arm participants (n=170) were instructed to play the Safe City mobile game for 4 weeks, whereas control arm participants (n=170) received a safety booklet. All participants completed a survey on safety knowledge and behaviors and psychosocial problems at baseline (T1), 1 month postintervention (T2), and 3 months postintervention (T3). Cumulative game scores and mini-game performance were analyzed as a proxy for the extent of exposure to the game. Outcome data were analyzed using 2-sample 2-tailed t tests to compare mean change from T1 to T2 and to T3 for intervention versus control arm participants. The association of game use with outcome changes postintervention was analyzed using generalized additive models., Results: No significant differences were found in mean changes between the intervention and control arms. However, use analyses showed that higher game scores were associated with improvements in safe behavior (P=.03) and internalizing problems (P=.01) at T3. Matching and Spot the Danger mini-game performance significantly predicted improvements in safety knowledge at T2 and T3., Conclusions: Analysis of use has shown that playing the Safe City mobile game can result in significant improvements in safety knowledge and reductions in unsafe behavior and internalizing problems. These findings provide evidence for the positive impact of serious games on psychological and social well-being, highlighting the potential of technology-driven interventions to assist children in learning about safety and preventing injuries., Trial Registration: ClinicalTrials.org NCT04096196; https://clinicaltrials.gov/show/NCT04096196., International Registered Report Identifier (irrid): RR2-10.2196/17756., (©Rosa S Wong, Keith T S Tung, Frederick K W Ho, Wilfred H S Wong, Chun Bong Chow, Ko Ling Chan, King Wa Fu, Patrick Ip. Originally published in the Journal of Medical Internet Research (https://www.jmir.org), 14.02.2024.)

Objective: This study is to evaluate if there is any difference in the balance between incidence of and remission from overweight/obesity in Hong Kong school-age children before and during the COVID-19 pandemic over three years., Methods: This is a retrospective longitudinal study that involved children aged 6-16 years from a database of the School Physical Fitness Award Scheme., Results: 2765 students were longitudinally followed up for two years. The prevalence of childhood overweight/obesity was increased between the 2019 and 2021 academic years (P < 0.001). During the COVID-19 pandemic, the rate of obesity remission significantly reduced by 7.9 % (P = 0.003), at a background of a plateau of obesity among children and adolescents., Conclusions: Our study provides evidence on the impact of school closure and home confinement as a standard infection control measure for the prevention of COVID-19, which are likely to break the balance between incidence of and remission from childhood obesity., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Purpose of Review: Pregnant women are vulnerable to mental health problems. Increasing evidence shows that omega-3 polyunsaturated fatty acid (n-3 PUFA) intake during pregnancy is beneficial to maternal perinatal mental health. A systematic review is needed to examine the associations reported in recent studies. The objective of this review was to provide an updated review on the association of antenatal n-3 PUFA intake via different sources (seafood, fish, overall diet, and supplementation) with perinatal mental health problems including depression, anxiety, and psychological distress., Recent Findings: Searches were performed in Web of Science, Embase, PubMed, and APA PsycInfo databases on 21 June 2021. A total of 2133 records were screened. Data including the name of the first author, publication year, study design, sample characteristics, dietary assessment time and tools, mental health outcome measures, and other relevant information were extracted. In total, 13 articles were included in this review and assessed qualitatively. The results demonstrated that dietary intake of n-3 PUFA during pregnancy was associated with perinatal mental health, but the effect of n-3 PUFA supplementation was influenced by pre-existing medical conditions, socio-demographic characteristics, and dietary and lifestyle patterns during pregnancy. Our review found that sources of n-3 PUFA may have differential effects on woman's mental health during and after pregnancy. Further research using large-size cohort or well-controlled trial protocol is needed to determine the effect of n-3 PUFA supplementation during pregnancy on perinatal mental health., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: Sex differences in the pathogenesis of hypertension exist. While gut microbiota (GM) has been associated with hypertension, it is unclear whether there are sex-linked differences in the association between GM and hypertension., Methods: We conducted a cross-sectional study to investigate the sex differences in associations between GM characterized by shotgun sequencing, GM-derived short-chain fatty acids, and 24-hour ambulatory blood pressure in 241 Hong Kong Chinese (113 men and 128 women; mean age, 54±6 years)., Results: The hypertensive group was associated with GM alterations; however, significant differences in β-diversity and GM composition in hypertensive versus normotensive groups were only observed in women and not in men under various statistical models adjusting for the following covariates: age, sex, body mass index, sodium intake estimated by spot urine analysis, blood glucose, triglycerides, low- and high-density lipoprotein cholesterol, smoking, menopause, and fatty liver status. Specifically, Ruminococcus gnavus , Clostridium bolteae , and Bacteroides ovatus were significantly more abundant in the hypertensive women, whereas Dorea formicigenerans was more abundant in the normotensive women. No bacterial species were found to be significantly associated with hypertension in men. Furthermore, total plasma short-chain fatty acids and propionic acid were independent predictors of systolic and diastolic blood pressure in women but not men., Conclusions: GM dysregulation was strongly associated with 24-hour ambulatory blood pressure in women but not men, which may be mediated through propionic acid. Our work suggests that sex differences may be an important consideration while assessing the role of GM in the development and treatment of hypertension., Competing Interests: Disclosures K.K. Lau received grants from Research Fund Secretariat of the Food and Health Bureau, Innovation and Technology Bureau, Research Grants Council, Amgen, Boehringer Ingelheim, Eisai, and Pfizer and consultation fees from Amgen, Boehringer Ingelheim, Daiichi Sankyo, and Sanofi, all outside the submitted work. S.Y. Leung has received research sponsorship from Pfizer, Merck, Servier, and Curegenix. S.K. Chung received a faculty research grant (FRG-22-024-FMD) and Dr Neher’s Biophysics Laboratory for Innovative Drug Discovery from the Macao Science and Technology Development Fund (FDCT project code: 001/2020/ALC), all outside of the submitted work. The other authors report no conflicts.

Background: The prevalence and consequences of child maltreatment are alarming, but evidence from studies with long follow-up intervals are limited. This study examined the long-term consequences of child maltreatment in relation to age of onset and follow-up interval., Methods: The exposed group comprised 63 individuals (aged 13-34 years) with a first-time diagnosis of child maltreatment between 2001 and 2010, whereas the unexposed group comprised 63 individuals who were matched upon gender, age of onset, follow-up period, and poverty status at the index hospital admission but had no medical records of maltreatment in Hong Kong. The participants completed a set of questionnaires on executive functions and mental health and provided blood samples for measurement of IL-6 and IL-10 levels during a health assessment session., Results: Compared with the unexposed group, the exposed group reported poorer maternal care during childhood (β = -4.64, p < 0.001) and had lower family support (β = -2.97, p = 0.010) and higher inflammatory responses (IL-6: β = 0.15, p = 0.001; IL-10: β = 0.11, p = 0.011) at follow-up. Additionally, the associations of childhood maltreatment exposure with family support and maternal care differed by age of onset and the length of time since exposure., Conclusions: This matched cohort study highlights childhood maltreatment as a risk factor for systemic inflammation and an indicator of suboptimal social environment, both of which could persist over a long period of time., (© 2022. The Author(s).)

There is lacking a population-based study on the fitness level of Hong Kong schoolchildren, and it seems that increasing childhood obesity prevalence has shifted the classification of healthy fitness, with 'underfit' as normal. This cross-sectional territory study aimed to develop an age- and sex-specific physical fitness reference using a representative sample of children aged 6-17 and to determine the associations with body mass index in schoolchildren. The study analyzed Hong Kong School Physical Fitness Award Scheme data covering grade 1 to grade 12 students' physical fitness and anthropometric measurements from 2017 to 2018. This reference was established without the impact due to COVID-19. Four aspects of physical fitness tests were measured using a standardized protocol, including (i) upper limb muscle strength, (ii) one-minute sit-up, (iii) sit-and-reach, and (iv) endurance run tests. The generalized additive model for location, scale, and shape was used to construct the reference charts. A Mann-Whitney U test was used to compare the mean differences in age, weight, and height, and a Pearson's chi-square test was used to examine the distributions of sex groups. A Kruskal-Wallis test was used to compare the group differences in BMI status, followed by the Dunn test for pairwise comparisons. A 5% level of significance was regarded as statistically significant. Data of 119,693 students before the COVID-19 pandemic were included in the analysis. The association between physical fitness level and BMI status varied depending on the test used, and there were significant differences in fitness test scores among BMI groups. The mean test scores of the obese group were lower in most of the tests for both boys and girls, except for handgrip strength. The underweight group outperformed the obese group in push-ups, one-minute sit-ups, and endurance run tests, but not in handgrip strength. In conclusion, a sex- and age-specific physical fitness reference value for Hong Kong Chinese children aged 6 to 17 years old is established, and this study demonstrated a nonlinear relationship between BMI status and physical fitness. The reference will help to identify children with poor physical fitness to offer support and guidance on exercise training. It also serves as a baseline for assessing the impact of the COVID-19 pandemic on Hong Kong students' physical fitness.

Context: Effect size estimates for the association between vitamin D concentrations in maternal blood during pregnancy and in cord blood vary widely across studies, but no meta-analysis has been conducted to ascertain this association., Objective: The aim of this systematic review was to estimate the pooled effect size for the association between circulating 25-hydroxyvitamin D (25[OH]D) concentrations, a marker of vitamin D status, in maternal blood during pregnancy and in cord blood., Data Sources: The PubMed, Embase, and Web of Science databases were searched from their inception to February 2021., Data Extraction: Following the application of prespecified inclusion and exclusion criteria, 94 articles were eligible for full-text review, which was conducted by 2 authors independently. A third author was consulted when necessary and consensus reached. In total, 26 articles, which comprised 30 studies and 6212 mother-infant dyads, were included. Methodological quality was assessed using a modified version of the Joanna Briggs Institute's Critical Appraisal Checklist for Studies Reporting Prevalence Data. Correlation coefficient (r) values for the association between maternal serum 25(OH)D concentrations during pregnancy and in cord blood were extracted., Data Analysis: The r values were pooled using random-effects meta-analyses. Sensitivity and subgroup analyses were performed to investigate sources of heterogeneity. The pooled r for all studies was 0.72 (95%CI, 0.64-0.79), indicating high heterogeneity (I2 = 95%, P < 0.01). After influential and outlier studies were removed, the pooled r for 9 studies was 0.70 (95%CI, 0.66-0.74), which resulted in a substantial reduction in heterogeneity (I2 = 41%, P=0.10)., Conclusion: The findings support a positive and large correlation between maternal vitamin D concentrations during pregnancy and vitamin D concentrations in cord blood., Systematic Review Registration: PROSPERO registration number CRD42021273348., (© The Author(s) 2022. Published by Oxford University Press on behalf of the International Life Sciences Institute. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Despite concerns about the negative effects of social distancing and prolonged school closures on children's lifestyle and physical activity (PA) during the COVID-19 pandemic, robust evidence is lacking on the impact of the pandemic-related school closures and social distancing on children's wellbeing and daily life. This study aimed to examine changes in the PA levels, sleep patterns, and screen time of school-aged children during the different phases of the COVID-19 outbreak in Hong Kong using a repeated cross-sectional design. School students (grades 1 to 12) were asked to report their daily electronic device usage and to fill in a sleep diary, recording their daily sleep onset and wake-up time. They were equipped with a PA monitor, Actigraph wGT3X-BT, to obtain objective data on their PA levels and sleep patterns. Students were recruited before the pandemic (September 2019-January 2020; n = 577), during school closures (March 2020-April 2020; n = 146), and after schools partially reopened (October 2020-July 2021; n = 227). Our results indicated lower PA levels, longer sleep duration, and longer screen time among participants recruited during school closures than those recruited before the COVID-19 outbreak. Primary school students were found to sleep on average for an extra hour during school closures. The later sleep onset and increased screen time documented during school closures persisted when schools partially reopened. Our findings illustrate the significant impact of social distancing policies during the COVID-19 pandemic on the sleep pattern, screen time, and PA level in school-aged children in Hong Kong. Professionals should urgently reinforce the importance of improving physically activity, good sleep hygiene, and regulated use of electronic devices for parents and school-aged children during this unprecedented time.

Background: Injury is an increasingly pressing global health issue. An effective surveillance system is required to monitor the trends and burden of injuries., Objective: This study aimed to identify a set of valid and context-specific injury indicators to facilitate the establishment of an injury surveillance program in Hong Kong., Methods: This development of indicators adopted a multiphased modified Delphi research design. A literature search was conducted on academic databases using injury-related search terms in various combinations. A list of potential indicators was sent to a panel of experts from various backgrounds to rate the validity and context-specificity of these indicators. Local hospital data on the selected core indicators were used to examine their applicability in the context of Hong Kong., Results: We reviewed 142 articles and identified 55 indicators, which were classified into 4 domains. On the basis of the ratings by the expert panel, 13 indicators were selected as core indicators because of their good validity and high relevance to the local context. Among these indicators, 10 were from the construct of health care service use, and 3 were from the construct of postdischarge outcomes. Regression analyses of local hospitalization data showed that the Hong Kong Safe Community certification status had no association with 5 core indicators (admission to intensive care unit, mortality rate, length of intensive care unit stay, need for a rehabilitation facility, and long-term behavioral and emotional outcomes), negative associations with 4 core indicators (operative intervention, infection rate, length of hospitalization, and disability-adjusted life years), and positive associations with the remaining 4 core indicators (attendance to accident and emergency department, discharge rate, suicide rate, and hospitalization rate after attending the accident and emergency department). These results confirmed the validity of the selected core indicators for the quantification of injury burden and evaluation of injury-related services, although some indicators may better measure the consequences of severe injuries., Conclusions: This study developed a set of injury outcome indicators that would be useful for monitoring injury trends and burdens in Hong Kong., (©Keith T S Tung, Rosa S Wong, Frederick K Ho, Ko Ling Chan, Wilfred H S Wong, Hugo Leung, Ming Leung, Gilberto K K Leung, Chun Bong Chow, Patrick Ip. Originally published in JMIR Public Health and Surveillance (https://publichealth.jmir.org), 18.08.2022.)

Background: Children with special educational needs (SEN) are more vulnerable during the COVID-19 pandemic with risk of poor mental wellbeing and child maltreatment., Objective: To examine the impact of COVID-19 on the mental health of children with SEN and their maltreatment risk., Participants and Setting: 417 children with SEN studying at special schools and 25,427 children with typical development (TD) studying at mainstream schools completed an online survey in April 2020 in Hong Kong during school closures due to COVID-19., Method: Emotional/behavioural difficulties, quality of life and parental stress of children with SEN were compared with typically developed children using mixed effect model. Linear regression analyses were performed to explore factors associated with child emotional/behavioural difficulties and parental stress during the pandemic. Chi-square test was performed to detect the differences in maltreatment risk before and during COVID-19., Results: Children with SEN had significantly poorer overall quality of life (68.05 vs 80.65, p < 0.01). 23.5% of children had at least one episode of severe physical assault and 1.9% experienced very severe physical assault during COVID-19. Rates of physical assault increased significantly (59.8% vs. 71.2% p < 0.001) while children with mental disorders had increased risk of severe physical assault comparing to those without mental disorders (RR = 1.58, ꭓ 2  = 5.19 p = 0.023)., Conclusion: Children with SEN had poorer mental health than typically developed children during the COVID-19 pandemic. Maltreatment risk for children with SEN is higher in comparison to pre-COVID-19 era. Surveillance of child maltreatment, continuity of medical and rehabilitation care to support children with SEN are essential during a disease pandemic., (Copyright © 2021. Published by Elsevier Ltd.)

Vitamin D is essential for human health. However, it is not clear if vitamin D supplementation is necessary for all pregnant women. This study examines the relative importance of dietary patterns and vitamin D supplementation frequency in determining serum 25-hydroxyvitamin D (25(OH)D) and ferritin concentrations among pregnant women in Hong Kong, China. A total of 572 healthy women were recruited from antenatal clinics at 25-35 weeks pregnant. Participants completed an electronic version of the food frequency questionnaire and a web questionnaire on supplement use. Their blood samples were tested for serum 25(OH)D and ferritin. The associations of dietary patterns and vitamin D supplementation frequency with serum 25(OH)D and ferritin concentrations were analyzed using moderated hierarchical regression. Two dietary patterns were identified. The adequate dietary intake was characterized by the high probability of meeting recommended daily food group servings, whereas the inadequate dietary intake was characterized by inadequate consumption of vegetables, fruits, meat, fish, and eggs, or alternatives. The association between adequate dietary intake and serum ferritin concentrations was independent of vitamin D supplementation frequency (β = 0.05, p = 0.035), but dietary patterns interacted with vitamin D supplementation frequency to determine serum 25(OH)D concentrations (β = -13.22, p = 0.014). The current study presents evidence on the relative importance of dietary patterns and vitamin D supplementation in maintaining sufficient vitamin D and iron in pregnancy. Antenatal nutrition counselling services should be provided to pregnant women who show signs of inadequate dietary intake.

Rising income inequality is strongly linked to health disparities, particularly in regions where uneven distribution of wealth and income has long been a concern. Despite emerging evidence of COVID-19-related health inequalities for adults, limited evidence is available for children and their parents. This study aimed to explore subtypes of families of preschoolers living in the disadvantaged neighborhoods of Hong Kong based on patterns of family hardship and to compare their patterns of parenting behavior, lifestyle practices, and wellbeing during the COVID-19 pandemic. Data were collected from 1338 preschoolers and their parents during March to June 2020. Latent class analysis was performed based on 11 socioeconomic and disease indicators. Multivariate logistic regressions were used to examine associations between identified classes and variables of interest during the COVID-19 pandemic. Four classes of family hardship were identified. Class 1 (45.7%) had the lowest disease and financial burden. Class 2 (14.0%) had the highest financial burden. Class 3 (5.9%) had the highest disease burden. Class 4 (34.5%) had low family income but did not receive government welfare assistance. Class 1 (low hardship) had lower risks of child maltreatment and adjustment problems than Class 2 (poverty) and Class 3 (poor health). However, children in Class 1 (low hardship) had higher odds of suffering psychological aggression and poorer physical wellbeing than those in Class 4 (low income), even after adjusting for child age and gender. The findings emphasize the need to adopt flexible intervention strategies in the time of large disease outbreak to address diverse problems and concerns among socially disadvantaged families.

There has been a lack of high-quality evidence concerning the association between childhood maltreatment and psychiatric diagnoses particularly for Axis II disorders. This study aimed to examine the association between childhood maltreatment exposure and Axis I and Axis II psychiatry disorders using electronic health records. In this study, the exposed group (n = 7473) comprised patients aged 0 to 19 years with a first-time record of maltreatment episode between January 1, 2001 and December 31, 2010, whereas the unexposed group (n = 26,834) comprised individuals of the same gender and age who were admitted into the same hospital in the same calendar year and month but had no records of maltreatment in the Hong Kong Clinical Data Analysis and Reporting System (CDARS). Data on their psychiatric diagnoses recorded from the date of admission to January 31, 2019 were extracted. A Cox proportional hazard regression model was fitted to estimate the hazard ratio (HR, plus 95% CIs) between childhood maltreatment exposure and psychiatric diagnoses, adjusting for age at index visit, sex, and government welfare recipient status. Results showed that childhood maltreatment exposure was significantly associated with subsequent diagnosis of conduct disorder/ oppositional defiant disorder (adjusted HR, 10.99 [95% CI 6.36, 19.01]), attention deficit hyperactivity disorder (ADHD) (7.28 [5.49, 9.65]), and personality disorders (5.36 [3.78, 7.59]). The risk of psychiatric disorders following childhood maltreatment did not vary by history of childhood sexual abuse, age at maltreatment exposure, and gender. Individuals with a history of childhood maltreatment are vulnerable to psychiatric disorders. Findings support the provision of integrated care within the primary health care setting to address the long-term medical and psychosocial needs of individuals with a history of childhood maltreatment., (© 2022. The Author(s).)

Much research on children in high-risk environments has focused on the biological consequences of maltreatment, adversity, and trauma. Whether other early-life stress sources such as family financial hardship are implicated in the cellular mechanism of disease development remains unclear. This study investigated the long-term effect of childhood exposure to family financial pressure on telomere length. It involved two waves of data collection occurring when participants reached Grade 3 (W1) and 7 (W2), respectively. In W1, parents reported family demographics and perceived financial stressors and pressure. In W2, participants provided buccal swab samples for measurement of their telomere length. Data from 92 participants (M age in W2 = 13.2 years; 56.5% male) were analyzed. The main type of stressors reported by parents who perceived high family financial pressure in W1 were child-level stressors including affordability of their medical and educational expenses. Participants exposed to high parent-perceived family financial pressure in W1 had shorter telomeres in W2 when compared to those exposed to low parent-perceived family financial pressure (β = -0.61, p = 0.042). Subgroup analyses revealed stronger associations in girls than boys. These findings reveal an important spillover effect between parental financial perceptions and stress and children's health at the cellular level.

Background: Antimicrobial resistance is an increasingly important issue in public health as antibiotics are overused. Resistance to antimicrobial agents can pose significant challenges to infection treatment., Objectives: To evaluate risk factors associated with carriage of antimicrobial-resistant (AMR) bacteria in children in the Asia-Pacific region to consolidate evidence for future implementation of antibiotic prescribing practice., Methods: Three electronic databases-PubMed, EMBASE and Cochrane Library-were searched. Observational studies that investigated the risk factors for carriage of MRSA, penicillin-resistant Streptococcus pneumoniae , ESBL-producing Escherichia coli and Klebsiella pneumoniae among the paediatric population in community settings in the Asia-Pacific region were considered eligible. Summary statistics from the identified studies were pooled using meta-analyses., Results: From the 4145 search results, 25 papers were included in this review. Sixteen papers were included in the meta-analysis based on reported risk factors. Young age of 2-6 months compared with children aged 7-60 months (OR 2.74, 95% CI: 1.75-4.29), antibiotic use within the past 3 months (OR 2.65, 95% CI: 1.70-4.12), daycare attendance (OR 1.49, 95% CI: 1.17-1.91) and hospital admission within the past 3 months (OR 3.43, 95% CI: 2.13-5.51) were found to be significant risk factors for AMR bacterial carriage, whilst breastfeeding (OR 0.69, 95% CI: 0.60-0.81) and concurrent colonization of S. pneumoniae (OR 0.59, 95% CI: 0.38-0.91) are protective factors., Conclusions: The findings support that there are a number of significant risk factors associated with carriage of AMR bacteria in the Asia-Pacific paediatric population. To combat antimicrobial resistance in the future, these risk factors should be considered, and measures taken to mitigate associated carriage., (© The Author(s) 2022. Published by Oxford University Press on behalf of British Society for Antimicrobial Chemotherapy.)

The evidence as to whether caffeine consumption is beneficial or harmful to human health has been mixed. This study aimed to examine the effect of 25-hydroxyvitamin D (25(OH)D) concentration on the association between caffeine consumption and mineral metabolism in pregnant women. This is a cross-sectional study involving pregnant women at their 25th to 35th gestational week recruited at antenatal clinics in the period of July 2019 to December 2020. Peripheral blood samples were collected to determine their total 25(OH)D, albumin, alkaline phosphatase (ALP), calcium, phosphate, and ferritin level in serum. Questionnaires on demographics and dietary intake were also administered. Among 181 pregnant women recruited (Average age = 32.9 years), 50 (27.6%) of them were found to be vitamin D insufficient (25(OH)D concentration < 75 nmol/L), and 131 (72.4%) were vitamin D sufficient (25(OH)D concentration ≥ 75 nmol/L). Adjusted regression models identified an association between higher caffeine intake and lower ALP level only among vitamin D-sufficient pregnant women (β = −0.24, p = 0.006), but not in those with insufficient vitamin D (β = −0.02, p = 0.912). The findings provide new insights into 25(OH)D concentration as a potential modifier of the health effects of caffeine consumption during pregnancy.

During the COVID-19 lockdown, with social distancing measures in place and a decrease in social activities, emotional states are more likely to be transferred between family members via increased interactions and communication. However, longitudinal evidence, particularly for early adolescents, is lacking. This study investigated family pre-pandemic influences on parental stress and adolescent psychosocial wellbeing during the COVID-19 pandemic. Data were collected from 233 adolescents and their parents before and during the initial phase of the pandemic. Parents reported their own stress level and perception of adolescent adjustment problems, whereas adolescents reported their own psychological distress level. In addition, adolescents also reported their satisfaction with family life in the pre-pandemic survey. Cross-lagged path models indicated reciprocal associations between parental stress and perception of adolescent adjustment problems. Compared to adolescents low in pre-pandemic family life satisfaction, those adolescents with higher levels of family life satisfaction before the pandemic reported lower levels of anxiety and stress only when parental stress showed no increase during the pandemic. Findings provide support for the mutual influences between parental stress and perceived adolescent adjustment problems during the pandemic. Special attention should be paid to those adolescents who undergo significant family life changes during the pandemic., Competing Interests: Conflict of interestAll authors have indicated they have no potential conflicts of interest to disclose., (© The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2022.)

The graded association between family socioeconomic status (SES) and physical fitness is evident, but little is known about the mechanism underlying this association. This study investigated the role of early-life activities as mediators of the longitudinal relationship between early-life SES and health-related physical fitness in 168 adolescents (51.2% boys; final mean age: 12.4 years old). In Wave 1 (2011-12), their parents completed questionnaires about family socioeconomic status (SES), parent-child activities, and child screen time. In Wave 2 (2014-15), participants' physical activity levels were assessed through parent proxy-reports. In Wave 3 (2018-19), a direct assessment of handgrip strength, standing long-jump, and 6-min walk test (6MWT) performance was conducted. After controlling for demographic factors, results of mediation analyses revealed that (a) Wave 1 SES predicted Wave 3 long-jump and 6MWT performance; (b) child physical activity level in Wave 2 mediated the relation between Wave 1 SES and standing long-jump performance in Wave 3; and (c) recreational parent-child activities and child screen time in wave 1 mediated the relation between Wave 1 SES and 6MWT performance in Wave 3. Our findings suggest that the type and frequency of early-life activities play a role in the graded association between childhood SES and physical fitness in adolescence., (© 2022. The Author(s).)

A growing body of research suggests an association between attention deficit hyperactivity disorder (ADHD) and allergic disorders, but little work has been done to explore the role of external factors such as parental smoking at home in the development of comorbid ADHD and allergic disorders. This study aimed to examine the association between allergic diseases and ADHD adjusted for exposure to parental smoking at home in early adolescents. We recruited 250 male (41.7%) and 350 female (58.3%) adolescents (mean [SD] age, 13.29 [0.52] years) via chain-referral sampling. Their ADHD symptoms were assessed by the parent proxy-report version of the Chinese Strengths and Weaknesses of Attention-Deficit/Hyperactivity-symptoms and Normal-behaviours (SWAN) rating scale. Data on the participants' history of clinician-diagnosed allergic diseases, family socio-demographics, and parental smoking habit were collected using a parent-completed questionnaire. Regression analyses were performed to examine the associations of interest. The levels of ADHD symptoms were comparable between allergic and non-allergic participants after controlling for child and family demographics and parental smoking at home. Notably, the risk of probable ADHD was particularly high in participants with food allergies (odd ratio = 4.51, p = 0.011) but not in those with allergic rhinitis after adjusting for parental smoking at home. Our findings suggest that second-hand smoke exposure at home is a potential risk factor underlying the link between ADHD and allergic diseases. Current management guidelines should emphasize the importance of early identification and cessation of tobacco smoke exposure for prevention of comorbidity of ADHD and allergic disorders. Clinical Trial Registration (if any): NA., Competing Interests: Conflict of InterestAll authors have indicated they have no potential conflicts of interest to disclose., (© The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2022.)

Background: The coronavirus disease 2019 (COVID-19) pandemic is having a profound impact on the health and development of children worldwide. There is limited evidence on the impact of COVID-19 and its related school closures and disease-containment measures on the psychosocial wellbeing of children; little research has been done on the characteristics of vulnerable groups and factors that promote resilience., Methods: We conducted a large-scale cross-sectional population study of Hong Kong families with children aged 2-12 years. Parents completed an online survey on family demographics, child psychosocial wellbeing, functioning and lifestyle habits, parent-child interactions, and parental stress during school closures due to COVID-19. We used simple and multiple linear regression analyses to explore factors associated with child psychosocial problems and parental stress during the pandemic., Results: The study included 29,202 individual families; of which 12,163 had children aged 2-5 years and 17,029 had children aged 6-12 years. The risk of child psychosocial problems was higher in children with special educational needs, and/or acute or chronic disease, mothers with mental illness, single-parent families, and low-income families. Delayed bedtime and/or inadequate sleep or exercise duration, extended use of electronic devices were associated with significantly higher parental stress and more psychosocial problems among pre-schoolers., Conclusions: This study identifies vulnerable groups of children and highlights the importance of strengthening family coherence, adequate sleep and exercise, and responsible use of electronic devices in promoting psychosocial wellbeing during the COVID-19 pandemic., (© 2020. Springer-Verlag GmbH Germany, part of Springer Nature.)

Background and Objectives: Interventions on adolescent drinking have yielded mixed results. We assessed the effectiveness of an Internet quiz game intervention compared to conventional health education., Methods: In this cluster randomized controlled trial with parallel group design, we randomly allocated 30 participating schools to the Internet quiz game intervention or the conventional health education (comparison) group, with 1:1 ratio. Students of Hong Kong secondary schools (aged 12-15 years) were recruited. The intervention was a 4-week Web-based quiz game competition in which participating students answered 1000 alcohol-related multiple-choice quiz questions. The comparison group received a printed promotional leaflet and hyperlinks to alcohol-related information., Results: Of 30 eligible schools, 15 (4294 students) were randomly assigned to the Internet quiz game intervention group and 15 (3498 students) to the comparison group. Average age of participants was 13.30 years. No significant between-group differences were identified at baseline. Overall retention rate for students was 86.0%. At 1-month follow-up, fewer students in the intervention group reported drinking (9.8% vs 12.1%, risk ratio 0.79, 95% confidence interval [CI] 0.68 to 0.92; P = .003), and those who drank reported drinking less alcohol (standardized difference β -0.06, 95% CI -0.11 to -0.01; P = .02). Between-group differences remained statistically significant at 3-month follow-up (10.4% vs 11.6%, risk ratio 0.86, 95% CI 0.74 to 0.999; P = .048; β -0.06, 95% CI -0.11 to -0.01; P = .02)., Conclusions: The Internet quiz game intervention reduced underage drinking by 21% at 1-month and 14% at 3-month follow-up compared with conventional health education., Competing Interests: POTENTIAL CONFLICT OF INTEREST: The authors have indicated they have no potential conflicts of interest to disclose., (Copyright © 2021 by the American Academy of Pediatrics.)

Rapid repeat pregnancy (RRP) often occurs in teenage and young mothers. Mothers with a history of RRP are more likely to experience high stress increasing their risk of child maltreatment. Despite these challenges, some mothers can continue to cope adaptively. Social support may play a role in empowering these mothers to overcome the childbearing difficulties. Although the protective effects of social support are well recognized, there has been little evidence on the relative importance of sources of support. For example, whether support from family and friends is equally important in relieving parenting stress remains unanswered. RRP, a social phenomenon encompassing various adverse living and parenting issues, provides an ideal research context to investigate the role of family and friends in preventing child maltreatment. This study examined whether family cohesion and friends' support moderated the association between RRP and child maltreatment in young mothers. We recruited 392 Chinese teenage and young mothers from a population-based integrated young mothers supporting program in Hong Kong. Questionnaires on pregnancy history, family cohesion, social support, and risk of child maltreatment were administered. Moderation analysis was conducted to examine the effect of RRP on child maltreatment as a function of family cohesion or friend support. Results showed that RRP was associated with a higher risk of child neglect (adjusted odds ratio [aOR] = 1.72, p < .05) and physical maltreatment (aOR = 1.91, p < .01), and that family cohesion was more important than friend support in mitigating the risk of child maltreatment for mothers with a history of RRP. Our findings suggest that interventions for young mothers, particularly those with a history of RRP, should be family-based so the whole family can be empowered to tackle the childrearing burden.

Importance: Stunting was used as a proxy for underdevelopment in early childhood in previous studies, but the associations between child development and other growth and body composition parameters were rarely studied., Objective: To estimate the association between malnutrition and early child development (ECD) at an individual level., Design, Setting, and Participants: This population-based, cross-sectional study used data from the East Asia Pacific Early Child Development Scales, a population-representative survey of children aged 3 to 5 years old, conducted in 2012 to 2014 in communities in Cambodia, China, Mongolia, Papua New Guinea, and Vanuatu. Data analysis was performed from November 2019 to April 2021., Exposures: Stunting (height-for-age [HFA] z score less than -2), wasting (weight-for-height z score less than -2), overweight (weight-for-height z score greater than 2), body mass index (BMI)-for-age z score, and body fat proportion based on existing growth standard and formula., Main Outcomes and Measures: ECD directly assessed using the validated East Asia-Pacific ECD Scales., Results: A total of 7108 children (3547 girls; mean [SD], age 4.48 [0.84] years) were included in this study. The prevalence of stunting was 27.1% (range across countries, 1.2%-55.0%), that of wasting was 13.7% (range, 5.4%-35.9%), and that of overweight was 15.9% (range, 2.2%-53.7%). Adjusted for country variations, age, sex, urbanicity, family socioeconomic status, and body fat proportion, ECD was linearly associated with HFA (β, 1.57; 95% CI, 1.35-1.80) and BMI-for-age (β, 0.64; 95% CI, 0.45-0.82). After adjustment for BMI and height, better ECD was associated with low body fat proportion (β, 0.93; 95% CI, 0.45-1.42). The association of HFA was more pronounced in Southeast Asia and the Pacific region than in East Asia, and the association of fat proportion was specific to children living in urban environments., Conclusions and Relevance: HFA, BMI-for-age, and body fat proportion were independently associated with ECD, and these findings suggest that future studies should consider using these parameters to estimate the prevalence of child underdevelopment; nutritional trials should examine to what extent the associations are causal.

Background: Exposure to suboptimal intrauterine environment might induce structural and functional changes that can affect neonatal health. Telomere length as an important indicator of cellular health has been associated with increased risk for disease development., Objectives: This study was aimed to examine the independent and combined effects of maternal, obstetric, and foetal factors on cord blood telomere length (TL)., Methods: Pregnant women at the gestational age of 20 th to 24 th week who attended the antenatal clinic of a major local hospital in Hong Kong were recruited. Participants were asked to complete a questionnaire on demographics, health-related quality of life, and history of risk behaviors. Medical history including pregnancy complications and neonatal outcomes was obtained from electronic medical records of both mother and neonate. Umbilical cord blood was collected at delivery for TL determination., Results: A total of 753 pregnant women (average age: 32.18 ± 4.51 years) were recruited. The prevalence of maternal infection, anaemia, and hypertension during pregnancy was 30.8%, 30.0%, and 6.0%, respectively. The adjusted regression model displayed that maternal infection was negatively associated with cord blood TL ( β = -0.18, p = 0.026). This association became even stronger in the presence of antenatal anaemia, hypertension, delivery complications, or neonatal jaundice ( β = -0.25 to -0.45)., Conclusions: This study consolidates evidence on the impact of adverse intrauterine environment at the cellular level. Maternal infection was significantly associated with shorter cord blood TL in a unique manner such that its presence may critically determine the susceptibility of telomere to other factors., Competing Interests: The authors have no conflicts of interest relevant to this article to disclose., (Copyright © 2021 Keith T. S. Tung et al.)

There is inconsistent evidence on the association between prenatal substance exposure and child behavioral problems. Children affected by maternal substance misuse are vulnerable to physical abuse and neglect. Few studies have examined factors contributing to internalizing and externalizing problems in these children. This study, with a focus on children with prenatal substance exposure, investigated whether family characteristics (the duration of maternal substance misuse postpartum or the existence of a sibling) moderated the association between adverse exposure (physical abuse or neglect) and behavior (internalizing or externalizing problems). We recruited 54 Hong Kong Chinese mothers with registered records of substance misuse during pregnancy and their children (2-9 years). Mothers completed questionnaires on drug use patterns during pregnancy and postpartum, abusive and neglectful parenting behaviors in the preceding year, and children's current behavioral problems. Moderated regression analyses tested whether abusive and neglectful parenting behavior interacted with family characteristics to affect child behavioral problems. The existence of a sibling moderated the relationship between neglect experience and internalizing problems, with a positive relationship observed only among single children (adjusted B [95% confidence interval] = 3.70 [0.98, 6.41], p = .012). The duration of maternal substance misuse postpartum moderated the relationship between physical abuse experience and externalizing problems, with a positive relationship observed only among children of mothers abusing substances beyond the child's infancy period (adjusted B [95% confidence interval] = 6.86 [2.34, 11.38], p = .008). The results show that the impact of physical abuse and neglect experiences depend on the type of behavior assessed and family and child characteristics. Positive sibling relationship and early detoxification in the mother can foster healthy behavioral development for children exposed prenatally to maternal substance misuse.

Family meals are beneficial for adolescent development, but evidence from Chinese populations has been limited. This study aimed to examine the associations between family meal frequency and adolescent perception of family relationship and compliance with parental guidance in Hong Kong. During the period from October to December 2016, a stratified random sample of 3359 students were recruited from 25 secondary schools in Hong Kong. Students completed questionnaires about family characteristics, relationship quality, and meal frequency by paper-and-pencil in class. Multiple regression analyses were conducted to examine the associations between family meal frequency and perceived family relationship and compliance with parental guidance overall and by subgroups. After adjusting for sociodemographic and school confounders, family breakfast and dinner frequency were significantly associated with adolescent compliance (breakfast: B = 0.07, p < 0.001; dinner: B 0.07, p < 0.001) and perception of family relationship (breakfast: B = 0.10, p < 0.001; dinner: B = 0.25, p < 0.001). Risk factors for infrequent family meals included older age, not born in Hong Kong, less educated fathers, and unmarried parents. Our findings support the associations of regular family meals with adolescent perception of high family bond and compliance with parental guidance. Interventions are needed to enhance quality family meal interactions in disadvantaged families.

Atopic diseases can impose a significant burden on children and adolescents. Telomere length is a cellular marker of aging reflecting the impact of cumulative stress exposure on individual health. Since elevated oxidative stress and inflammation burden induced by chronic atopy and snoring may impact telomere length, this study aimed to investigate whether snoring would moderate the relationship between atopic diseases and telomere length in early adolescence. We surveyed 354 adolescents and their parents. Parents reported the adolescents' history of atopic diseases, recent snoring history as well as other family sociodemographic characteristics. Buccal swab samples were also collected from the adolescents for telomere length determination. Independent and combined effects of atopic diseases and snoring on telomere length were examined. Among the surveyed adolescents, 174 were reported by parents to have atopic diseases (20 had asthma, 145 had allergic rhinitis, 53 had eczema, and 25 had food allergy). Shorter TL was found in participants with a history of snoring and atopic diseases (β = -0.34, p = 0.002) particularly for asthma (β = -0.21, p = 0.007) and allergic rhinitis (β = -0.22, p = 0.023). Our findings suggest that snoring in atopic patients has important implications for accelerated telomere shortening. Proper management of atopic symptoms at an early age is important for the alleviation of long-term health consequences at the cellular level.

Background: Although an increasing body of research shows that excessive screen time could impair brain development, whereas non-screen recreational activities can promote the development of adaptive emotion regulation and social skills, there is a lack of comparative research on this topic. Hence, this study examined whether and to what extent the frequency of early-life activities predicted later externalizing and internalizing problems., Methods: In 2012/13, we recruited Kindergarten 3 (K3) students from randomly selected kindergartens in two districts of Hong Kong and collected parent-report data on children's screen activities and parent-child activities. In 2018/19, we re-surveyed the parents of 323 students (aged 11 to 13 years) with question items regarding their children's externalizing and internalizing symptoms in early adolescence. Linear regression analyses were conducted to examine the associations between childhood activities and psychosocial problems in early adolescence., Results: Early-life parent-child activities (β = -0.14, p = 0.012) and child-alone screen use duration (β = 0.15, p = 0.007) independently predicted externalizing problems in early adolescence. Their associations with video game exposure (β = 0.19, p = 0.004) and non-screen recreational parent-child activities (β = -0.14, p = 0.004) were particularly strong., Conclusions: Parent-child play time is important for healthy psychosocial development. More efforts should be directed to urge parents and caregivers to replace child-alone screen time with parent-child play time.

Background: Existing studies on health-related quality of life (HRQoL) mainly covered single growth stages of childhood or adolescence and did not report on the trends in the relationships of HRQoL with sleep duration, physical activity, and screen time. This study aimed to establish the population norm of HRQoL in children and adolescents aged 6-17 years and examine the associations of screen time, sleep duration, and physical activity with HRQoL in this population., Methods: We conducted a large-scale cross-sectional population-based survey study of Hong Kong children and adolescents aged 6 to 17 years. A representative sample of students were interviewed to assess their HRQoL using PedsQL and EQ-5D-Y-5L. Multivariable homoscedastic Tobit regression with linear form or restricted cubic spline of predictors was used to analyze the associations between screen time, sleep duration, and HRQoL. Multiple imputation by chained equations was performed to deal with missing data., Results: A total of 7555 respondents (mean age 11.5, SD 3.2; 55.1% female) were sampled. Their EQ VAS scores, PedsQL physical summary scores, and psychosocial summary scores were positively correlated with sleep duration and moderate/vigorous activity but was negatively correlated with screen time., Conclusions: Children and adolescents who had longer exposure to screen, shorter sleep duration, and lower physical activity levels appeared to have poorer HRQoL as assessed by PedsQL and EQ-5D-Y-5L. Advice and guidance on screen time allocation for children and adolescents should be provided at the levels of school, community, and family.

Importance: Schools were closed intermittently across Hong Kong to control the COVID-19 outbreak, which led to significant physical and psychosocial problems among children and youths., Objective: To compare the clinical characteristics and sources of infection among children and youths with COVID-19 during the 3 waves of outbreaks in Hong Kong in 2020., Design, Setting, and Participants: This cross-sectional study involved children and youths aged 18 years or younger with COVID-19 in the 3 waves of outbreaks from January 23 through December 2, 2020. Data were analyzed from December 2020 through January 2021., Main Outcomes and Measures: Demographic characteristics, travel and contact histories, lengths of hospital stay, and symptoms were captured through the central electronic database. Individuals who were infected without recent international travel were defined as having domestic infections., Results: Among 397 children and youths confirmed with COVID-19 infections, the mean (SD) age was 9.95 (5.34) years, 220 individuals (55.4%) were male, and 154 individuals (38.8%) were asymptomatic. There were significantly more individuals who were infected without symptoms in the second wave (59 of 118 individuals [50.0%]) and third wave (94 of 265 individuals [35.5%]) than in the first wave (1 of 14 individuals [7.1%]) (P = .001). Significantly fewer individuals who were infected in the second and third waves, compared with the first wave, had fever (first wave: 10 individuals [71.4%]; second wave: 22 individuals [18.5%]; third wave: 98 individuals [37.0%]; P < .001) or cough (first wave: 6 individuals [42.9%]; second wave: 15 individuals [12.7%]; third wave: 52 individuals [19.6%]; P = .02). Among all individuals, 394 individuals (99.2%) had mild illness. One patient developed chilblains (ie, COVID toes), 1 patient developed multisystem inflammatory syndrome in children, and 1 patient developed post-COVID-19 autoimmune hemolytic anemia. In all 3 waves, 204 patients with COVID-19 (51.4%) had domestic infections. Among these individuals, 186 (91.2%) reported having a contact history with another individual with COVID-19, of which most (183 individuals [90.0%]) were family members. In the third wave, 18 individuals with domestic infections had unknown contact histories. Three schoolmates were confirmed with COVID-19 on the same day and were reported to be close contacts., Conclusions and Relevance: This cross-sectional study found that nearly all children and youths with COVID-19 in Hong Kong had mild illness. These findings suggest that household transmission was the main source of infection for children and youths with domestic infections and that the risk of being infected at school was small.

Background : During the coronavirus disease 2019 (COVID-19) pandemic, the implementation of social distancing and home confinement measures may elevate the risk of vitamin D deficiency particularly for infants. This study aimed to quantify changes in vitamin D level among infants and toddlers in Hong Kong after the COVID-19 outbreak. Methods: We recruited 303 infants and toddlers aged 2-24 months by stratified random sampling from 1 June 2019 to November 30, 2020. Regression models were used to estimate the effect of time on infants' serum 25-hydroxyvitamin D (25(OH)D) level overall and by age groups before and after the outbreak. Interrupted time series (ITS) analysis was performed to examine the sustained effect of COVID-19 on their serum 25(OH)D level. Results: The ITS results showed no immediate reduction in serum 25(OH)D level among infants, but a decreasing trend was observed in the subsequent months post-outbreak at a monthly decline rate of -6.32 nmol/L. When analyzed by age group, the magnitude of post-outbreak reduction in 25(OH)D was stronger among younger infants (aged 2-6 months). Conclusion: Guidelines and recommendations should be given to pregnant women and mothers to ensure sufficient vitamin D level in their infants during the COVID-19 period.

Recent evidence suggests that breastfeeding may increase the risk of vitamin D deficiency in offspring. However, it is unclear whether increased risk results from breastfeeding alone, or whether it is associated together with other risk factors. This study surveyed 208 infant-mother dyads recruited by stratified random sampling in different districts of Hong Kong. Mothers were asked to complete a questionnaire on their demographics, history of risk behavior, and feeding practices. Peripheral blood samples were collected from infants to determine their vitamin D status. Among all infant participants, 70 were vitamin D insufficient or deficient. Being breastfed, being a girl, having a multiparous mother, and the use of sun cream were found to be the strongest risk factors for vitamin D insufficiency during infancy (all p < 0.05), after mutual adjustment. The cumulative risk model displayed a dose-response pattern between the number of risk factors and the risk of vitamin D insufficiency during this period. Our findings indicate the risk profile of infants with insufficient vitamin D. Guidelines and recommendations on healthy diet and lifestyle should be provided to mothers during the early stage of pregnancy to increase the likelihood of adequate levels of vitamin D in their offspring.

Objectives: This study aimed to identify key factors affecting Healthcare workers (HCWs) perceived stress and risk of contracting COVID-19 among themselves and their family members during the pandemic. Methods: A cross-sectional online questionnaire study was conducted between 19 March and April 5, 2020 in Hong Kong. HCWs from public hospitals and private dentists, and their family members participated. Results: A total of 747 HCWs and 245 family members participated. Higher perceived stress in HCWs was associated with more negative changes in family relationship ( p = 0.025). The HCWs' perceived stress, however, was positively associated with family cohesion ( p = 0.033) and stress levels of family members ( p < 0.001). The level of HCWs' satisfaction toward the hospital policies in response to the COVID-19 outbreak was associated with lower levels of perceived stress and risk of themselves or their family members contracting COVID-19. HCWs' previous frontline experience of SARS was significantly associated with less perceived risk of themselves or their family members contracting COVID-19. Conclusion: Hospital policies addressing HCWs' needs, frontline experience of SARS, and family relationship influenced psychological wellbeing of HCWs during the COVID-19 outbreak., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Chua, Tung, Kwan, Wong, Chui, Li, Wong, Tso, Fu, Chan, Wing, Chen, Chun Lee, Rao, Chan, Hon, Hung, Lau, Ho, Wong, Xiong, Chi, Tang, Tam, Wong and Ip.)

Growing evidence has shown that exposure to harsh parenting and child maltreatment elevate the risk of Internet addiction in adolescence. Yet, limited research has examined the mechanisms underlying this association. The present study was a cross-sectional school survey of 1204 adolescents (52.2 % male and 47.8 % female; mean age, 13.36 years) in Hong Kong. The adolescents completed a self-reported questionnaire about their exposure to bullying victimization, bullying perpetration, child maltreatment, Internet addiction, and social support. The findings showed that harsh parenting and maltreatment was significantly associated with Internet addiction. After controlling for a number of confounding factors, the results of the mediation analyses showed that family support and bullying perpetration, and family support and bullying victimization accounted for 36 % and 25 % of the effect of harsh discipline and maltreatment on Internet addiction, respectively. Effective prevention and intervention strategies for Internet addiction should target family and social vulnerabilities in adolescents., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Quantification of injury burden is vital for injury prevention, as it provides a guide for setting policies and priorities. This study generated a set of Hong Kong specific disability weights (DWs) derived from patient experiences and hospital records. Patients were recruited from the Accident and Emergency Department (AED) of three major trauma centers in Hong Kong between September 2014 and December 2015 and subsequently interviewed with a focus on health-related quality of life at most three times over a 12-month period. These patient-reported data were then used for estimation of DWs. The burden of injury was determined using the mortality and inpatient data from 2001 to 2012 and then compared with those reported in the UK Burden of Injury (UKBOI) and global burden of diseases (GBD) studies. There were 22,856 mortality cases and 817,953 morbidity cases caused by injuries, in total contributing to 1,027,641 disability-adjusted life years (DALYs) in the 12-year study timeframe. Estimates for DALYs per 100,000 in Hong Kong amounted to 1192, compared with 2924 in UKBOI and 3459 in GBD. Our findings support the use of multiple data sources including patient-reported data and hospital records for estimation of injury burden.

Objective: To disentangle the pathways of parent technology use, parent-child interactions, child screen time, and child psychosocial difficulties among disadvantaged families in Hong Kong., Study Design: Parents of 1254 3-year-old children from the KeySteps@JC project reported on the number of hours their children used electronic devices every day and evaluated their children's psychosocial behaviors using the Strengths and Difficulties Questionnaire. These parents also reported on their own digital device usage patterns and the frequency of parent-child interactions and provided sociodemographic data. Structural models were tested with parent technology use (independent variable), parent technological distractions and parent-child interactions and child screen time (mediators), child psychosocial problems (dependent variable), and children's age and sex and family socioeconomic status index (confounding variables)., Results: Parent distraction with technology during parent-child interactions completely mediated the overall association between parent problematic digital technology use and child screen use duration. Parent problematic digital technology use was positively and directly associated with child psychosocial difficulties. In addition, it was indirectly related to child psychosocial difficulties through technological distractions and reductions in parent-child interactions and increased media use by children., Conclusion: Higher parent digital technology usage was associated with reduced parent-child interactions and increased child screen time and psychosocial difficulties in disadvantaged families. These results suggest that limiting parents' use of electronic devices in front of their young children could be beneficial for childhood psychosocial development., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Introduction: Body mass index (BMI) categories and physical fitness are associated but the reciprocal relationship between BMI categories and physical fitness has not been investigated. This study aims to investigate the longitudinal reciprocal relationship between BMI categories and physical fitness., Methods: This is a population-based 4-year cohort study in 48 elementary schools. Children aged 6 to 9 years at recruitment were included. BMI categories and physical fitness including handgrip strength, core muscle endurance, flexibility, and cardiorespiratory fitness were measured using standard equipment and protocol., Results: Among 26 392 eligible participants, 19 504 (73.9%) were successfully followed for 3 years. Baseline obesity prevalence was 5.9%. After 3 years, those who were unfit at baseline had an increased risk of obesity (risk ratio [RR] 1.41, 95% CI 1.16-1.71, P < .001) and those who were fit at baseline had a decreased risk of obesity (RR 0.69, 95% CI 0.60-0.80, P < .001) compared with moderately fit children. Furthermore, improvement of fitness predicted decreased risk of obesity. Similarly, normal body weight also predicted better physical fitness. The path analysis confirmed a strong reciprocal relationship between physical fitness and obesity., Conclusions: Better physical fitness was prospectively associated with normal weight and vice versa. Physically fit children were more likely to maintain a healthy weight and those with a healthy weight were more likely to be physically fit, which is important for healthy development., (© 2020 World Obesity Federation.)

Objectives: To compare the clinical and laboratory features of severe acute respiratory syndrome 2003 (SARS) and coronavirus disease 2019 (COVID-19) in 2 Chinese pediatric cohorts, given that the causative pathogens and are biologically similar., Study Design: This is a cross-sectional study reviewing pediatric patients with SARS (n = 43) and COVID-19 (n = 244) who were admitted to the Princess Margaret Hospital in Hong Kong and Wuhan Children's Hospital in Wuhan, respectively. Demographics, hospital length of stay, and clinical and laboratory features were compared., Results: Overall, 97.7% of patients with SARS and 85.2% of patients with COVID-19 had epidemiologic associations with known cases. Significantly more patients with SARS developed fever, chills, myalgia, malaise, coryza, sore throat, sputum production, nausea, headache, and dizziness than patients with COVID-19. No patients with SARS were asymptomatic at the time of admission, whereas 29.1% and 20.9% of patients with COVID-19 were asymptomatic on admission and throughout their hospital stay, respectively. More patients with SARS required oxygen supplementation than patients with COVID-19 (18.6 vs 4.7%; P = .004). Only 1.6% of patients with COVID-19 and 2.3% of patients with SARS required mechanical ventilation. Leukopenia (37.2% vs 18.6%; P = .008), lymphopenia (95.4% vs 32.6%; P < .01), and thrombocytopenia (41.9% vs 3.8%; P < .001) were significantly more common in patients with SARS than in patients with COVID-19. The duration between positive and negative nasopharyngeal aspirate and the length in hospital stay were similar in patients with COVID-19, regardless of whether they were asymptomatic or symptomatic, suggesting a similar duration of viral shedding., Conclusions: Children with COVID-19 were less symptomatic and had more favorable hematologic findings than children with SARS., (Copyright © 2020 Elsevier Inc. All rights reserved.)