Physical Fitness and Body Mass Index Status of Hong Kong Primary Schoolchildren across the COVID-19 Pandemic, before and after School Closure.

OBJECTIVE: To determine whether health-related physical fitness and body mass index (BMI) status differed before and after school closure from the COVID-19 pandemic in a population-based cohort of Hong Kong primary schoolchildren. STUDY DESIGN: We examined the BMI z score, BMI status, and physical fitness z scores including (i) upper limb muscle strength, (ii) 1-minute sit-up test, (iii) sit-and-reach test, and (iv) endurance run tests, among 3 epochs: prepandemic (September 2018-August 2019), before school closure (September 2019-January 2020), and partial school reopening (September 2021-August 2022), using a repeated cross-sectional approach. RESULTS: A total of 137 752 primary schoolchildren aged 6-12 years were recruited over 3 academic years. Obesity increased significantly from 25.9% in 2018/19 to 31.0% in 2021/22, while underweight increased slightly from 6.1% to 6.5%. All tested parameters were adversely affected by the pandemic. The negative trend over time was far more pronounced in all 4 physical fitness scores in the underweight group, although performance in handgrip strength had no significance between 2018/19 and 2021/22. CONCLUSIONS: Schoolchildren who are both underweight and overweight/obese are vulnerable to adverse changes in physical fitness during the COVID-19 pandemic. To eliminate the negative health and fitness outcomes, it is urgent to develop strategies for assisting schoolchildren in achieving a healthy weight, especially in the postpandemic era.

Changes in, and factors associated with family functioning: results of four cross-sectional household surveys from 2011 to 2017 in Hong Kong.

BACKGROUND: Previous research has well-documented that family functioning is an important predictor of individuals' physical and mental health. However, relatively little research has explored family functioning at the family and population levels, such as changes in family functioning across years and whether predictors of family functioning differ across different family structures. Understanding of the changes in family functioning across years and factors promoting family functioning will inform the development of preventive measures to enhance family health and resilience. Objectives of the study were: (1) to examine the changes in family functioning across a 6-year study period and (2) to study protective factors associated with family functioning and the extent to which the factors are the same or different across different family structures. METHOD: The study involved secondary data analysis of the biannual Family Survey carried out by the Family Council, an advisory body to the Hong Kong government. A series of ANOVA and regression analyses were conducted using data of four population-based cross-sectional household surveys conducted in Hong Kong in 2011, 2013, 2015, and 2017. RESULTS: There were some fluctuations in overall family functioning scores across the study period, but no significant difference was found between the scores in 2011 and 2017. Different predictors of family functioning were found for different family types, and frequent family communication was a common protective factor for most family types, including never married, married/cohabiting with children, and married/cohabiting with no children. CONCLUSION: The study is among the first to examine changes in family functioning at the population level. Monitoring and addressing family functioning may help tackle various social problems and future public health crises. Interventions to promote family functioning should address both common and different protective factors of different family types.

Effect of a Mobile Game-Based Intervention to Enhance Child Safety: Randomized Controlled Trial.

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.

Building a baby-friendly community: Development, strategy, implementation and evaluation of a BFCI program.

AIM: The aim of the study was to investigate the impact of the use of baby-friendly community initiative (BFCI) model on various stakeholders in the community. DESIGN: Quasi-experimental research design. METHOD: The study was conducted in public premises and online workshops from April 2019 to September 2022. Participants were followed up for a period of 1 month, except for those employed at public premises. The program involved training based on an accredited BFCI framework to cultivate a breastfeeding-friendly attitude and knowledge. A paired sample t-test was used to examine breastfeeding attitude and knowledge scores before and after BFCI training among staff employed from public premises. An analysis of variance was conducted to examine the breastfeeding self-efficacy and attitude scores, measured repeatedly at different timepoints over 1-month timepoint (T0, T1 and T2) among pregnant and postpartum women. RESULTS: A total of 2340 perinatal women and 1339 staff from public premises were recruited. For staff, there was an increase in the mean score of breastfeeding knowledge and attitude by 5.8 and 6.1, respectively, at T1. Similarly, for perinatal women, there was an increase in the mean score of breastfeeding self-efficacy and attitude by 6.6 and 3.3, respectively, at T1. CONCLUSION: In summary, a BFCI model, with active community participation, accreditation and an award system, has been effective in promoting breastfeeding. Adapting the baby-friendly hospital initiative to local contexts and employing a social theory model can enhance breastfeeding promotion and improve infant health outcomes. Prioritizing culturally sensitive breastfeeding education is crucial for successful BFCI implementation. IMPLICATIONS FOR THE PROFESSION AND/OR PATIENT CARE: Healthcare professionals should consider clients' culture and socio-economic backgrounds when providing breastfeeding education to maximize effectiveness. The target audience for breastfeeding education should be expanded to include various community stakeholders beyond families. IMPACT: What problem did the study address? This study addressed the problem of knowledge gaps among stakeholders in building a breastfeeding-friendly community, particularly in implementing a baby-friendly community initiative (BFCI) as part of a baby-friendly hospital initiative (BFHI). The research filled a service gap by providing effective interventions targeting community stakeholders and assessing the impact of a BFCI program on their knowledge and attitudes towards breastfeeding. What were the main findings? The findings highlighted the effectiveness of a BFCI program in enhancing breastfeeding knowledge and attitudes among frontline staff and increasing breastfeeding confidence among mothers. These findings contribute to the understanding of the program's impact on different stakeholders in the community. Where and on whom will the research have an impact? It impacts on global policymakers by providing insights for developing comprehensive guidelines for future BFCI implementations. It also contributes to the creation of a more baby-friendly community, benefiting breastfeeding families and their infants by promoting and supporting breastfeeding families. REPORTING METHOD: This study has adhered to relevant EQUATOR guidelines using the TREND reporting guideline. PATIENT OR PUBLIC CONTRIBUTION: No patient or public contribution. WHAT DOES THIS PAPER CONTRIBUTE TO THE WIDER GLOBAL CLINICAL COMMUNITY?: This study provides an overview of the establishment of a localized BFCI program. It also opens up a new direction for the community to investigate BFCI strategies for community stakeholders. It also provides evidence to support other countries in following a similar process, as each country approaches becoming breastfeeding-friendly in its own unique way. TRIAL AND PROTOCOL REGISTRATION: No protocol.

Early-life family and school impacts on adolescent conduct problems: A path analysis.

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.

Natural history of infants with vitamin D deficiency in Hong Kong.

BACKGROUND AND OBJECTIVES: The usual recommended intake of vitamin D for healthy infants is 400 international unit (IU) daily. However, a high dose of vitamin D at 2000-3000 IU daily is needed for those with vitamin D deficiency (VDD). This study aimed to assess the natural history of a group of healthy infants with VDD and the associated factors for persistent VDD. METHODS AND STUDY DESIGN: Healthy infants detected to have VDD (25OHD <25 nmol/L) in a population study were followed, and their demographics and clinical data were collected. RESULTS: One hundred and thirty-one subjects (boys = 66%) were included. Their first serum 25OHD was taken at a median age of 87.5 days. None were treated with high-dose vitamin D supplements, but some have been given vitamin D at 400 IU daily. They were assessed again at the median age of 252.5 days when 15 remained to have VDD and 26 were in the insufficient range (25 - 49.9nmol/L). All persistent VDD children were on exclusive breastfeeding. Exclusive breastfeeding and no vitamin D supplementation were significant risk factors for persistent vitamin D insufficiency (<50nmol/L). CONCLUSIONS: Persistent VDD is common among infants exclusively breastfeeding and those who did not receive vitamin D supplementation.

Intimate Partner Violence Against Women Before, During, and After Pregnancy: A Meta-Analysis.

Intimate partner violence (IPV) against pregnant women negatively impacts women's and infants' health. Yet inconsistent results have been found regarding whether pregnancy increases or decreases the risk of IPV. To answer this question, we systematically searched for studies that provided data on IPV against women before pregnancy, during pregnancy, and after childbirth. Nineteen studies met our selection criteria. We meta-analyzed the nineteen studies for the pooled prevalence of IPV across the three periods and examined study characteristics that moderate the prevalence. Results showed the pooled prevalence estimates of IPV were 21.2% before pregnancy, 12.8% during pregnancy and 14.7% after childbirth. Although these findings suggest a reduction in IPV during pregnancy, our closer evaluation of the prevalence of IPV after childbirth revealed that the reduction does not appear to persist. The prevalence of IPV increased from 12.8% within the first year after childbirth to 24.0% beyond the first year. Taken together, we should not assume pregnancy protects women from IPV, as IPV tends to persist across a longer-term period. Future studies are needed to investigate if IPV transits into other less obvious types of violence during pregnancy. Moderator analyses showed the prevalence estimates significantly varied across countries by income levels and regions.

Longitudinal associations between child discipline methods and physical growth patterns across preschool years.

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.

The Knowledge, Attitudes, and Practices of Healthy Eating Questionnaire: a pilot validation study in Chinese families.

Introduction: Identifying the knowledge, attitudes, and practices (KAP) gaps of healthy eating can inform the design of effective interventions. This study aimed to test the validity and psychometric properties of a KAP of Healthy Eating Questionnaire (KAP-HEQ) tailored to the Chinese culture. Methods: The dimensions and potential items of each KAP scale were identified from published KAP and health literacy questionnaires, which were supplemented by the findings of a previous qualitative healthy eating study. Content validity of the KAP-HEQ was evaluated by eight experts and eight Chinese parent-adolescent dyads in Hong Kong through content validity ratio (CVR), content validity index (CVI), and qualitative feedback. The feasibility, construct validity, reliability, and sensitivity of the KAP-HEQ were evaluated in this pilot study among 60 adolescent-parent dyads (120 persons) through an online survey. The first 30 dyads who completed the KAP-HEQ were invited to repeat the KAP-HEQ 2 weeks later to assess the test-retest reliability. Results: The final 44-item KAP-HEQ was completed in 10-15 min by both adolescents and their adult parents. The CVR ranged from -0.38 to 1, and the CVI ranged from 0.56 to 1. Over 80% of the items achieved convergent validity (a significantly positive correlation with its hypothesized scale) and discriminant validity (a higher correlation with its hypothesized scale than with the other two scales). Cronbach's alpha for the internal consistency of the Overall, Attitude, and Practice scales was >0.7, while that of the Knowledge scale was 0.54. The intraclass correlation coefficient (ICC) on test-retest reliability of the Overall and individual scales were all >0.75 except that of the Knowledge scale (ICC = 0.58). The significant differences in KAP scale scores with small to large effect sizes were found between known groups as hypothesized, except the Attitude score between groups by household income, which supported the sensitivity of the KAP-HEQ. Conclusion: The KAP-HEQ has shown good validity, reliability, and sensitivity among Chinese adolescents and adults, which can be applied to evaluate KAP status and gaps to inform the design and assess the effectiveness of healthy eating interventions.

The central role of natural killer cells in mediating acute myocarditis after mRNA COVID-19 vaccination.

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-1ß (IL-1ß), 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).

Effectiveness of a 5-year health empowerment programme on promoting cardiovascular health for adults from low-income families in Hong Kong.

OBJECTIVE: This study aimed to evaluate the effectiveness of a health empowerment programme (HEP) to enhance cardiovascular health for adults from low-income families. METHODS: A prospective cohort study (N = 219, Intervention group: n = 103, comparison group: n = 116) was conducted with participants recruited from January 2013 to November 2015 and followed up until January 2022. Throughout the study duration, intervention group were invited to participate in the HEP. The cardiovascular health status of both groups at baseline and follow-up were assessed using the adapted Ideal Cardiovascular Health Index (ICHI) defined by the American Heart Association. After inverse propensity score weighting, multiple linear regression and Poisson regression were employed to examine the effects of the HEP. RESULTS: The HEP was associated with a greater increase in ICHI total score (B = 0.33, p < 0.001), and the increase of proportion of people achieving a normal blood pressure (Incidence rate ratio: 3.39, p < 0.05). CONCLUSION: HEP can be an effective and sustainable strategy to reduce social disparities in cardiovascular health of adults from low-income families, as indicated by improvement in the ICHI total score and blood pressure status. PRACTICAL IMPLICATIONS: The sustainable HEP in the community setting has potential for generalizability and scalability to other financially challenged families.

A systematic review on the applicability of cell-free DNA level as an obesity biomarker.

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.

Genome-wide association study of BNT162b2 vaccine-related myocarditis identifies potential predisposing functional areas in Hong Kong adolescents.

Vaccine-related myocarditis associated with the BNT162b2 vaccine is a rare complication, with a higher risk observed in male adolescents. However, the contribution of genetic factors to this condition remains uncertain. In this study, we conducted a comprehensive genetic association analysis in a cohort of 43 Hong Kong Chinese adolescents who were diagnosed with myocarditis shortly after receiving the BNT162b2 mRNA COVID-19 vaccine. A comparison of whole-genome sequencing data was performed between the confirmed myocarditis cases and a control group of 481 healthy individuals. To narrow down potential genomic regions of interest, we employed a novel clustering approach called ClusterAnalyzer, which prioritised 2,182 genomic regions overlapping with 1,499 genes for further investigation. Our pathway analysis revealed significant enrichment of these genes in functions related to cardiac conduction, ion channel activity, plasma membrane adhesion, and axonogenesis. These findings suggest a potential genetic predisposition in these specific functional areas that may contribute to the observed side effect of the vaccine. Nevertheless, further validation through larger-scale studies is imperative to confirm these findings. Given the increasing prominence of mRNA vaccines as a promising strategy for disease prevention and treatment, understanding the genetic factors associated with vaccine-related myocarditis assumes paramount importance. Our study provides valuable insights that significantly advance our understanding in this regard and serve as a valuable foundation for future research endeavours in this field.

Insufficient Sleep is Associated With Increasing Trends in Adolescent Suicidal Behaviors.

PURPOSE: Youth suicide has been increasing and became a public health concern worldwide. Identifying insufficient sleep as the potential risk factor is critical to reducing suicide risk and increasing trends. This study aimed to determine whether insufficient sleep is associated with increasing trends in suicidal behaviors and disparities by sex, age, and race/ethnicity among school adolescents. METHODS: The present study used biennial data from the US nationally representative Youth Risk Behavior Survey from 2007 to 2019. Joinpoint regression models were used to estimate biennial percent changes (BPCs) and average BPCs (ABPCs) of suicidal behaviors by sleep duration. Logistic regression models were used to examine the association between insufficient sleep and suicidal behaviors. RESULTS: Of 73,356 adolescent students included (mean [standard deviation] age, 16.11 [1.23] years), 50.03% were female. Suicidal ideation and suicide plan among insufficient sleep group increased from 2007 to 2019 (BPC = 2.88% [95% confidence interval {CI}: 1.65%, 4.13%]; BPC = 3.42% [95% CI: 2.09%, 4.77%]), but were nonsignificant among sufficient sleep group. Trends in suicidal ideation (ABPC = 3.03% [95% CI: 1.35%, 4.73%]) and suicide plan (ABPC = 4.03% [95% CI: 2.47%, 5.62%]) among female adolescents with insufficient sleep increased, but nonsignificant among male adolescents with insufficient sleep. Suicidal ideation (ABPC = 1.73% [95% CI: 0.51%, 2.97%]) and suicide plan (ABPC = 2.31% [95% CI: 0.70%, 3.95%]) increased among younger adolescents only with insufficient sleep, whereas suicide trends by sleep duration were similar among older adolescents. Suicide plan among insufficient sleep group increased across the four racial groups, with BPC highest for the White (BPC = 3.48% [95% CI: 1.31%, 5.69%]), and lowest for the Hispanic/Latino (BPC = 1.18% [95% CI: 0.15%, 2.23%]), but were nonsignificant among sufficient sleep group except for the White (BPC = 2.83% [95% CI: 0.62%, 5.09%]). DISCUSSION: Insufficient sleep was disproportionately associated with increasing trends in suicidal behaviors among female, younger, and non-White adolescent students. Ensuring sufficient sleep can potentially reduce suicide among school adolescents.

Normative values of motor performance and their relationship with BMI status in Hong Kong preschoolers.

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 P50 and P95 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.

Latent Heterogeneity of Online Sexual Experiences and Associations With Sexual Risk Behaviors and Behavioral Health Outcomes in Chinese Young Adults: Cross-Sectional Study.

BACKGROUND: Online sexual experiences (OSEs) are becoming increasingly common in young adults, but existing papers have reported only on specific types of OSEs and have not shown the heterogeneous nature of the repertoire of OSEs. The use patterns of OSEs remain unclear, and the relationships of OSEs with sexual risk behaviors and behavioral health outcomes have not been evaluated. OBJECTIVE: This study aimed to examine the latent heterogeneity of OSEs in young adults and the associations with sexual risk behaviors and behavioral health outcomes. METHODS: The 2021 Youth Sexuality Study of the Hong Kong Family Planning Association phone interviewed a random sample of 1205 young adults in Hong Kong in 2022 (male sex: 613/1205, 50.9%; mean age 23.0 years, SD 2.86 years) on lifetime OSEs, demographic and family characteristics, Patient Health Questionnaire-4 (PHQ-4) scores, sex-related factors (sexual orientation, sex knowledge, and sexual risk behaviors), and behavioral health outcomes (sexually transmitted infections [STIs], drug use, and suicidal ideation) in the past year. Sample heterogeneity of OSEs was analyzed via latent class analysis with substantive checking of the class profiles. Structural equation modeling was used to examine the direct and indirect associations between the OSE class and behavioral health outcomes via sexual risk behaviors and PHQ-4 scores. RESULTS: The data supported 3 latent classes of OSEs with measurement invariance by sex. In this study, 33.1% (398/1205), 56.0% (675/1205), and 10.9% (132/1205) of the sample were in the abstinent class (minimal OSEs), normative class (occasional OSEs), and active class (substantive OSEs), respectively. Male participants showed a lower prevalence of the abstinent class (131/613, 21.4% versus 263/592, 44.4%) and a higher prevalence of the active class (104/613, 17.0% versus 28/592, 4.7%) than female participants. The normative class showed significantly higher sex knowledge than the other 2 classes. The active class was associated with male sex, nonheterosexual status, higher sex desire and PHQ-4 scores, and more sexual risk behaviors than the other 2 classes. Compared with the nonactive (abstinent and normative) classes, the active class was indirectly associated with higher rates of STIs (absolute difference in percentage points [Δ]=4.8%; P=.03) and drug use (Δ=7.6%; P=.001) via sexual risk behaviors, and with higher rates of suicidal ideation (Δ=2.5%; P=.007) via PHQ-4 scores. CONCLUSIONS: This study provided the first results on the 3 (abstinent, normative, and active) latent classes of OSEs with distinct profiles in OSEs, demographic and family characteristics, PHQ-4 scores, sex-related factors, and behavioral health outcomes. The active class showed indirect associations with higher rates of STIs and drug use via sexual risk behaviors and higher rates of suicidal ideation via PHQ-4 scores than the other 2 classes. These results have implications for the formulation and evaluation of targeted interventions to help young adults.

Association of vitamin D-binding protein polymorphisms and serum 25(OH)D concentration varies among Chinese healthy infants of different VDR-FokI genotypes: A multi-centre cross-sectional study.

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.

Effect of wearable activity trackers on physical activity in children and adolescents: a systematic review and meta-analysis.

BACKGROUND: Physical inactivity in children and adolescents has become a pressing public health concern. Wearable activity trackers can allow self-monitoring of physical activity behaviour and promote autonomous motivation for exercise. However, the effects of wearable trackers on physical activity in young populations remain uncertain. METHODS: In this systematic review and meta-analysis, we searched PubMed, Embase, SPORTDiscus, and Web of Science for publications from database inception up to Aug 30, 2023, without restrictions on language. Studies were eligible if they were randomised controlled trials or clustered randomised controlled trials that examined the use of wearable activity trackers to promote physical activity, reduce sedentary behaviours, or promote overall health in participants with a mean age of 19 years or younger, with no restrictions on health condition or study settings. Studies were excluded if children or adolescents were not the primary intervention cohort, or wearable activity trackers were not worn on users' bodies to objectively track users' physical activity levels. Two independent reviewers (WWA and FR) assessed eligibility of studies and contacted authors of studies if more information was needed to assess eligibility. We also searched reference lists from relevant systematic reviews and meta-analyses. Systematic review software Covidence was used for study screening and data extraction. Study characteristics including study setting, participant characteristics, intervention characteristics, comparator, and outcome measurements were extracted from eligible studies. The two primary outcomes were objectively measured daily steps and moderate-to-vigorous physical activity. We used a random-effects model with Hartung-Knapp adjustments to calculate standardised mean differences. Between-study heterogeneity was examined using Higgins I2 and Cochran Q statistic. Publication bias was assessed using Egger's regression test. This systematic review was registered with PROSPERO, CRD42023397248. FINDINGS: We identified 9619 studies from our database research and 174 studies from searching relevant systematic reviews and meta-analyses, of which 105 were subjected to full text screening. We included 21 eligible studies, involving 3676 children and adolescents (1618 [44%] were female and 2058 [56%] were male, mean age was 13·7 years [SD 2·7]) in our systematic review and meta-analysis. Ten studies were included in the estimation of the effect of wearable activity trackers on objectively measured daily steps and 11 were included for objectively measured moderate-to-vigorous physical activity. Compared with controls, we found a significant increase in objectively measured daily steps (standardised mean difference 0·37 [95% CI 0·09 to 0·65; p=0·013]; Q 47·60 [p<0·0001]; I2 72·7% [95% CI 53·4 to 84·0]), but not for moderate-to-vigorous physical activity (-0·08 [-0·18 to 0·02; p=0·11]; Q 10·26 [p=0·74]; I2 0·0% [0·0 to 53·6]). INTERPRETATION: Wearable activity trackers might increase daily steps in young cohorts of various health statuses, but not moderate-to-vigorous physical activity, highlighting the potential of wearable trackers for motivating physical activity in children and adolescents. More rigorously designed trials that minimise missing data are warranted to validate our positive findings on steps and to explore possible long-term effects. FUNDING: The Hong Kong University Grants Committee and Seed Fund for Basic Research of the University of Hong Kong.

Light exposure therapy for myopia control: a systematic review and Bayesian network meta-analysis.

AIMS: To compare and rank the myopia control effects of different light wavelengths in children using a systematic review and Bayesian network meta-analysis (Bayesian NMA). METHODS: The review protocol was registered with PROSPERO. We searched PubMed, EMBASE and MEDLINE for relevant clinical and animal studies published as of 2 February 2023. We included studies comparing red, violet or full-spectrum light with controls. Data extracted included descriptive statistics and study outcomes (axial length (AL) elongation and progression of spherical equivalent (SE) refraction). After quality assessment, estimates of treatment effect outcomes (mean differences (MDs) and 95% CIs) were first pooled for the animal and clinical studies in a traditional meta-analysis. To compare and rank the different light wavelengths, the Bayesian NMA was then conducted for all the included clinical studies (12 studies) and separately for only randomised controlled trials (8 studies). MDs, 95% credible intervals (CrIs) and ranks of the various light wavelengths were estimated in the Bayesian NMA. RESULTS: When all clinical studies were included in the Bayesian NMA (12 studies), only red-light significantly slowed AL elongation, MD (95% CrI), -0.38 mm (-0.59 mm to -0.16 mm)/year and SE refraction progression, 0.72D (0.35D to 1.10D)/year compared with controls. It remained the only significant intervention when effect sizes from only RCTs (eight studies) were separately combined, (-0.28 mm (-0.40 mm to -0.15 mm)/year and 0.57D (0.22D to 0.92D)/year, for AL and SE refraction, respectively). CONCLUSION: Myopia control efficacy varied among different wavelengths of light, with red light ranked as the most effective. PROSPERO REGISTRATION NUMBER: Clinical studies: CRD42022368998; animal studies: CRD42022368671.