Search

Abstract Background Inadequate and excessive gestational weight gain (GWG) defined by the Institute of Medicine (IOM) has been associated with preterm birth. However, studies demonstrate inconsistent associations. Objectives We examined the associations between categorical and continuous total GWG and moderate to late preterm birth (32- 200% of the recommendations, which is well above the IOM recommended upper limit. Conclusions Excessive GWG was associated with an increased risk of moderate to late preterm birth, with variation in the association by pre-pregnancy BMI. Current definitions of excessive GWG may not adequately reflect increased risk of preterm birth among those with overweight or obesity.

Abstract We hypothesize that children characterized by deprived factors have poorer health outcomes. We aim to identify clustering of determinants and estimate risk of early childhood diseases. This 1993–2019 longitudinal cohort study combines three Canadian pediatric cohorts and their families. Mothers and children are clustered using latent class analysis (LCA) by 16 indicators in three domains (maternal and newborn; socioeconomic status [SES] and neighbourhood; environmental exposures). Hazard ratios (HR) of childhood asthma, allergic rhinitis (AR), and eczema are quantified with Cox proportional hazard (PH) regression. Rate ratios (RR) of children’s health services use (HSU) are estimated with Poisson regression. Here we report the inclusion of 15,724 mother–child pairs; our LCA identifies four mother-clusters. Classes 1 and 2 mothers are older (30–40 s), non-immigrants with university education, living in high SES neighbourhoods; Class 2 mothers have poorer air quality and less greenspace. Classes 3 and 4 mothers are younger (20–30 s), likely an immigrant/refugee, with high school-to-college education, living in lower SES neighborhoods with poorer air quality and less greenspace. Children’s outcomes differ by Class, in comparison to Class 1. Classes 3 and 4 children have higher risks of asthma (HR 1.24, 95% CI 1.11–1.37 and HR 1.39, 95% CI 1.22–1.59, respectively), and similar higher risks of AR and eczema. Children with AR in Class 3 have 20% higher all-cause physician visits (RR = 1.20, 95% CI 1.10–1.30) and those with eczema have 18% higher all-cause emergency department visits (RR = 1.18, 95% CI 1.09–1.28) and 14% higher all-cause physician visits (RR = 1.14, 95% CI 1.09–1.19). Multifactorial-LCA mother-clusters may characterize associations of children’s health outcomes and care, adjusting for interrelationships.

Objectives Parents’ decisions to vaccinate their children against COVID-19 are complex and often informed by discussions with primary care physicians. However, little is known about physicians’ perspectives on COVID-19 vaccinations for children or their experiences counselling parents in their decision-making. We explored physicians’ experiences providing COVID-19 vaccination recommendations to parents and their reflections on the contextual factors that shaped these experiences.Design We conducted an interpretive qualitative study using in-depth interviews. We analyzed the data using reflexive thematic analysis and a socioecological framework.Setting This study involved primary care practices associated with The Applied Research Group for Kids (TARGet Kids!) primary care research network in the Greater Toronto Area, Ontario, Canada.Participants Participants were 10 primary care physicians, including family physicians, paediatricians and paediatric subspecialists.Results Participants discussed elements at the individual level (their identity, role, and knowledge), the interpersonal level (their relationships with families, responsiveness to parents’ concerns, and efforts to build trust) and structural level (contextual factors related to the evolving COVID-19 climate, health system pandemic response, and constraints on care delivery) that influenced their experiences providing recommendations to parents. Our findings illustrated that physicians’ interactions with families were shaped by a confluence of their own perspectives, their responses to parents’ perspectives, and the evolving landscape of the broader pandemic.Conclusions Our study underscores the social and relational nature of vaccination decision-making and highlights the multiple influences on primary care physicians’ experiences providing COVID-19 vaccination recommendations to parents. Our findings offer suggestions for future COVID-19 vaccination programmes for children. Delivery of new COVID-19 vaccinations for children may be well suited within primary care offices, where trusting relationships are established, but physicians need support in staying knowledgeable about emerging information, communicating available evidence to parents to inform their decision-making and dedicating time for vaccination counselling.

Abstract Background Children and their families often face obstacles in accessing mental health (MH) services. The purpose of this study was to develop and pilot test an electronic matching process to match children with virtual MH resources and increase access to treatment for children and their families during COVID-19. Methods Within a large observational child cohort, a random sample of 292 families with children ages 6–12 years were invited to participate. Latent profile analysis indicated five MH profiles using parent-reported symptom scores from validated depression, anxiety, hyperactivity, and inattention measures: (1) Average Symptoms, (2) Low Symptoms, (3) High Symptoms, (4) Internalizing, and (5) Externalizing. Children were matched with virtual MH resources according to their profile; parents received surveys at Time 1 (matching process explanation), Time 2 (match delivery) and Time 3 (resource uptake). Data on demographics, parent MH history, and process interest were collected. Results 128/292 families (44%) completed surveys at Time 1, 80/128 families (63%) at Time 2, and a final 67/80 families (84%) at Time 3, yielding an overall uptake of 67/292 (23%). Families of European-descent and those with children assigned to the Low Symptoms profile were most likely to express interest in the process. No other factors were associated with continued interest or uptake of the electronic matching process. Most participating parents were satisfied with the process. Conclusions The electronic matching process delivered virtual MH resources to families in a time-efficient manner. Further research examining the effectiveness of electronically matched resources in improving children’s MH symptoms is needed.

Abstract Background Growth studies rely on longitudinal measurements, typically represented as trajectories. However, anthropometry is prone to errors that can generate outliers. While various methods are available for detecting outlier measurements, a gold standard has yet to be identified, and there is no established method for outlying trajectories. Thus, outlier types and their effects on growth pattern detection still need to be investigated. This work aimed to assess the performance of six methods at detecting different types of outliers, propose two novel methods for outlier trajectory detection and evaluate how outliers affect growth pattern detection. Methods We included 393 healthy infants from The Applied Research Group for Kids (TARGet Kids!) cohort and 1651 children with severe malnutrition from the co-trimoxazole prophylaxis clinical trial. We injected outliers of three types and six intensities and applied four outlier detection methods for measurements (model-based and World Health Organization cut-offs-based) and two for trajectories. We also assessed growth pattern detection before and after outlier injection using time series clustering and latent class mixed models. Error type, intensity, and population affected method performance. Results Model-based outlier detection methods performed best for measurements with precision between 5.72-99.89%, especially for low and moderate error intensities. The clustering-based outlier trajectory method had high precision of 14.93-99.12%. Combining methods improved the detection rate to 21.82% in outlier measurements. Finally, when comparing growth groups with and without outliers, the outliers were shown to alter group membership by 57.9 -79.04%. Conclusions World Health Organization cut-off-based techniques were shown to perform well in few very particular cases (extreme errors of high intensity), while model-based techniques performed well, especially for moderate errors of low intensity. Clustering-based outlier trajectory detection performed exceptionally well across all types and intensities of errors, indicating a potential strategic change in how outliers in growth data are viewed. Finally, the importance of detecting outliers was shown, given its impact on children growth studies, as demonstrated by comparing results of growth group detection.

Abstract Background The timing of introduction to solid food has been associated with eczema and wheezing in childhood. Our aim was to determine whether differences persist within the recommended 4 to 6 month age range. Methods A longitudinal cohort study with repeated measures was conducted among children from birth to 10 years of age who were participating in the TARGet Kids! practice based research network in Toronto, Canada. The primary exposure was the timing of introduction to infant cereal as the first solid food. The primary outcome was eczema and the secondary outcome was wheezing collected by parent report using the validated International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire. Multinomial generalized estimating equations were used and effect modification by family history of asthma and breastfeeding duration were explored. Results Of the 7843 children included, the mean (standard deviation) age of introduction to infant cereal was 5.7 (1.9) months. There was evidence for family history of asthma and breastfeeding duration to be effect modifiers in the eczema (P = 0.04) and wheezing (P = 0.05) models. Introduction to infant cereal at 4 vs. 6 months of age was associated with higher odds of eczema (OR 1.62; 95% CI: 1.12, 2.35; P = 0.01) among children without a family history of asthma who were not breastfeeding when solid foods were introduced. Introduction to infant cereal at 4 vs. 6 months of age was associated with a higher odds of wheezing (OR 1.31; 95% CI: 1.13, 1.52; P

Abstract Background Evidence suggests that accelerated postnatal growth in children is detrimental for adult cardiovascular health. It is unclear whether children born late preterm (34–36 weeks) compared to full term (≥ 39 weeks), have different growth trajectories. Our objective was to evaluate the association between gestational age groups and growth trajectories of children born between 2006–2014 and followed to 2021 in Ontario, Canada. Methods We conducted a retrospective cohort study of children from singleton births in TARGet Kids! primary care network with repeated measures of weight and height/length from birth to 14 years, who were linked to health administrative databases. Piecewise linear mixed models were used to model weight (kg/month) and height (cm/month) trajectories with knots at 3, 12, and 84 months. Analyses were conducted based on chronological age. Results There were 4423 children included with a mean of 11 weight and height measures per child. The mean age at the last visit was 5.9 years (Standard Deviation: 3.1). Generally, the more preterm, the lower the mean value of weight and height until early adolescence. Differences in mean weight and height for very/moderate preterm and late preterm compared to full term were evident until 12 months of age. Weight trajectories were similar between children born late preterm and full term with small differences from 84–168 months (mean difference (MD) -0.04 kg/month, 95% CI -0.06, -0.03). Children born late preterm had faster height gain from 0–3 months (MD 0.70 cm/month, 95% CI 0.42, 0.97) and 3–12 months (MD 0.17 cm/month, 95% CI 0.11, 0.22). Conclusions Compared to full term, children born late preterm had lower average weight and height from birth to 14 years, had a slightly slower rate of weight gain after 84 months and a faster rate of height gain from 0–12 months. Follow-up is needed to determine if growth differences are associated with long-term disease risk.

BackgroundAn increase in child screen time has been observed throughout the COVID-19 pandemic. Home environment and parenting practices have been associated with child screen time. The purpose of this study was to examine associations between parental use of routines, limit setting, and child screen time during the (COVID-19) pandemic to inform harm-reducing strategies to limit the potential harms ensued by excessive screen use.MethodsA cohort study was conducted in 700 healthy children (3,628 observations) aged 0–11 years though the TARGet Kids! COVID-19 Study of Children and Families in Toronto, Canada from May 2020-May 2021. The independent variables assessed were parent-reported use of routines and setting limits. Outcomes were parent-reported child daily screen time in minutes and whether the Canadian 24-Hour screen time guideline was met, defined as 0 for 5 years. Linear and logistic mixed-effects models were fitted using repeated measures of independent variables and outcomes with a priori stratification by developmental stages (

Abstract Background It is well established that breast milk offers numerous health benefits for mother and child. Mothers are recommended to exclusively breastfeed their child until 6 months of age, with continued breastfeeding up to 1–2 years of age or beyond. Yet, these recommendations are met less than half of the time in high-income countries. Lactation consultants specialize in supporting mothers with breastfeeding and are a promising approach to improving breastfeeding rates. For lactation consultant interventions to be implemented widely as part of public health policy, a better understanding of their effect on breastfeeding rates and important health outcomes is needed. Methods The overall aim of this systematic review is to evaluate the effect of lactation consultant interventions provided to women, compared to usual care, on breastfeeding rates (primary outcome), maternal breastfeeding self-efficacy, and infant growth. A search strategy has been developed to identify randomized controlled trials published in any language between 1985 and April 2023 in CENTRAL, MEDLINE, EMBASE, CINAHL, Scopus, and Web of Science. We will also perform a search of the grey literature and reference lists of relevant studies and reviews. Two reviewers will independently extract data on study design, baseline characteristics, details of the interventions employed, and primary and secondary outcomes using a pre-piloted standardized data extraction form. Risk of bias and quality of evidence assessment will be done independently and in duplicate using the Cochrane Risk of Bias tool and GRADE approach, respectively. Where possible, meta-analysis using random-effects models will be performed, otherwise a qualitative summary will be provided. We will adhere to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Discussion This review will fill an important gap in the lactation support literature. The findings will be of importance to policymakers who seek to implement interventions to improve breastfeeding rates. Trial registration This review has been registered in the PROSPERO database (ID: CRD42022326597).

Abstract Background Heterogeneous mental health outcomes during the COVID-19 pandemic are documented in the general population. Such heterogeneity has not been systematically assessed in youth with autism spectrum disorder (ASD) and related neurodevelopmental disorders (NDD). To identify distinct patterns of the pandemic impact and their predictors in ASD/NDD youth, we focused on pandemic-related changes in symptoms and access to services. Methods Using a naturalistic observational design, we assessed parent responses on the Coronavirus Health and Impact Survey Initiative (CRISIS) Adapted For Autism and Related neurodevelopmental conditions (AFAR). Cross-sectional AFAR data were aggregated across 14 European and North American sites yielding a clinically well-characterized sample of N = 1275 individuals with ASD/NDD (age = 11.0 ± 3.6 years; n females = 277). To identify subgroups with differential outcomes, we applied hierarchical clustering across eleven variables measuring changes in symptoms and access to services. Then, random forest classification assessed the importance of socio-demographics, pre-pandemic service rates, clinical severity of ASD-associated symptoms, and COVID-19 pandemic experiences/environments in predicting the outcome subgroups. Results Clustering revealed four subgroups. One subgroup—broad symptom worsening only (20%)—included youth with worsening across a range of symptoms but with service disruptions similar to the average of the aggregate sample. The other three subgroups were, relatively, clinically stable but differed in service access: primarily modified services (23%), primarily lost services (6%), and average services/symptom changes (53%). Distinct combinations of a set of pre-pandemic services, pandemic environment (e.g., COVID-19 new cases, restrictions), experiences (e.g., COVID-19 Worries), and age predicted each outcome subgroup. Limitations Notable limitations of the study are its cross-sectional nature and focus on the first six months of the pandemic. Conclusions Concomitantly assessing variation in changes of symptoms and service access during the first phase of the pandemic revealed differential outcome profiles in ASD/NDD youth. Subgroups were characterized by distinct prediction patterns across a set of pre- and pandemic-related experiences/contexts. Results may inform recovery efforts and preparedness in future crises; they also underscore the critical value of international data-sharing and collaborations to address the needs of those most vulnerable in times of crisis.

Background Parent and child mental health has suffered during the pandemic and transition phase. Structured and shared parenting may be intervention targets beneficial to families who are struggling with parent or child mental health challenges. Aims First, we investigated associations between structured and shared parenting and parent depression symptoms. Second, we investigated associations between structured and shared parenting and depression, hyperactivity/inattention and irritability symptoms in children. Method A total of 1027 parents in two-parent households (4797 observations total; 85.1% mothers) completed online surveys about themselves and their children (aged 2–18 years) from April 2020 to July 2022. Structured parenting and shared parenting responsibilities were assessed from April 2020 to November 2021. Symptoms of parent depression, child depression, child hyperactivity and inattention, child irritability, and child emotional and conduct problems were assessed repeatedly (one to 14 times; median of four times) from April 2020 to July 2022. Results Parents who reported higher levels of shared parenting responsibilities had lower depression symptoms (β = −0.09 to −0.32, all P < 0.01) longitudinally. Parents who reported higher levels of shared parenting responsibilities had children with fewer emotional problems (ages 2–5 years; β = −0.07, P < 0.05), fewer conduct problems (ages 2–5 years; β = −0.09, P < 0.01) and less irritability (ages 13–18 years; β = −0.27, P < 0.001) longitudinally. Structured parenting was associated with fewer conduct problems (ages 2–5 years; β = −0.05, P < 0.05). Conclusions Shared parenting is beneficial for parent and child mental health, even under chaotic or inflexible life conditions. Structured parenting is beneficial for younger children.

Introduction There has been considerable debate about whether plant milks can support the nutritional requirements of growing children. The proposed systematic review aims to assess the evidence on the relationship between plant milk consumption and growth and nutritional status in childhood.Methods and analysis Ovid MEDLINE ALL (1946–present), Ovid EMBASE Classic (1947–present), CINAHL Complete (Cumulative Index to Nursing and Allied Health Literature), Scopus, the Cochrane Library and grey literature will be searched comprehensively (from 2000 to present; English language) to find studies that describe the association between plant milk consumption and growth or nutrition in children 1–18 years of age. Two reviewers will identify eligible articles, extract data and assess the risk of bias in individual studies. If a meta-analyses is not conducted, the evidence will be synthesised narratively and the overall certainty of evidence will be rated using the Grading of Recommendations Assessment, Development and Evaluation approach.Ethics and dissemination Ethical approval is not required for this study since no data will be collected. Results of the systematic review will be published in a peer-reviewed journal. Findings from this study may be useful in informing future evidence-based recommendations about plant milk consumption in children.PROSPERO registration number CRD42022367269.

Does the timing of when children, youth and adults participate in physical activity, sedentary behaviour (e.g. screen time) and sleep matter when it comes to their overall health? This special issue of Health Promotion and Chronic Disease Prevention in Canada includes four papers that present evidence and recommendations on the timing of movement behaviours: three separate systematic reviews exploring the associations between health indicators and the timing of physical activity, sedentary behaviour and sleep; and a commentary that discusses the importance of this evidence in terms of practice, policy and research. This editorial sets the stage for this special issue, reflecting on the challenges posed by COVID-19-related public health restrictions on healthy movement. Perhaps now is the optimal time to reimagine how and when we engage in physical activity, sedentary behaviour and sleep to support our health.

Est-ce que l’horaire auquel les enfants, les adolescents et les adultes sont actifs, demeurent sédentaires (par exemple devant un écran) et dorment ont une influence sur leur état de santé général? Ce numéro spécial de Promotion de la santé et prévention des maladies chroniques au Canada rassemble quatre articles qui présentent des données probantes et des recommandations concernant l’horaire des comportements en matière de mouvement : trois revues systématiques portant sur les associations entre les indicateurs de l’état de santé et les horaires d’activité physique, de sédentarité et de sommeil et un commentaire sur l’importance de ces données probantes pour les pratiques, les politiques et la recherche. Cet éditorial prépare le terrain pour ce numéro spécial en décrivant les effets des restrictions de santé publique liées à la COVID-19 sur un rythme favorable à la santé. Maintenant semble un moment idéal pour réévaluer de quelle manière et selon quel horaire nous devrions être physiquement actifs, demeurer sédentaires et dormir pour favoriser notre santé.

Abstract Background The primary aim of this study was to determine if screen use in early childhood is associated with overall vulnerability in school readiness at ages 4 to 6 years, as measured by the Early Development Instrument (EDI). Secondary aims were to: (1) determine if screen use was associated with individual EDI domains scores, and (2) examine the association between screen use and EDI domains scores among a subgroup of high screen users. Methods This prospective cohort study was carried out using data from young children participating in a large primary care practice-based research network in Canada. Logistic regression analyses were run to investigate the association between screen use and overall vulnerability in school readiness. Separate linear regression models examined the relationships between children’s daily screen use and each separate continuous EDI domain. Results A total of 876 Canadian participants participated in this study. Adjusted logistic regression revealed an association between increased screen use and increased vulnerability in school readiness (p = 0.05). Results from adjusted linear regression demonstrated an association between higher screen use and reduced language and cognitive development domain scores (p = 0.004). Among high screen users, adjusted linear regression models revealed associations between increased screen use and reduced language and cognitive development (p = 0.004) and communication skills and general knowledge domain scores (p = 0.042). Conclusions Screen use in early childhood is associated with increased vulnerability in developmental readiness for school, with increased risk for poorer language and cognitive development in kindergarten, especially among high users.

Background All longitudinal cohort studies strive for high participant retention, although attrition is common. Understanding determinants of attrition is important to inform and develop targeted strategies to improve study participation. We aimed to identify factors associated with research participation in a large children’s primary care cohort study. Methods In this longitudinal cohort study between 2008 and 2020, all children who participated in the Applied Research Group for Kids (TARGet Kids!) were included. TARGet Kids! is a large primary care practice-based pediatric research network in Canada with ongoing data collection at well-child visits. Several sociodemographic, health, and study design factors were examined for their associations with research participation. The primary outcome was attendance of eligible research follow-up visits. The secondary outcome was time to withdrawal from the TARGet Kids! study. Generalized linear mixed effects models and Cox proportional hazard models were fitted. We have engaged parent partners in all stages of this study. Results A total 10,412 children with 62,655 total eligible research follow-up visits were included. Mean age at enrolment was 22 months, 52% were male, and 52% had mothers of European ethnicity. 68.4% of the participants attended at least 1 research follow-up visit. Since 2008, 6.4% of the participants have submitted a withdrawal request. Key factors associated with research participation included child age, ethnicity, maternal age, maternal education level, family income, parental employment, child diagnosis of chronic health conditions, certain study sites, and missingness in questionnaire data. Conclusions Socioeconomic status, demographic factors, chronic conditions, and missingness in questionnaire data were associated with research participation in this large primary care practice-based cohort study of children. Results from this analysis and input from our parent partners suggested that retention strategies could include continued parent engagement, creating brand identity and communication tools, using multiple languages and avoiding redundancy in the questionnaires.

Abstract Background Robust measurement of dietary intake in population studies of children is critical to better understand the diet–health nexus. It is unknown whether parent proxy-report of children’s dietary intake through online 24-h recalls is feasible in large cohort studies. Objectives The primary objective of this study was to describe the feasibility of the Automated Self-Administered 24-h Dietary Assessment Tool (ASA24) to measure parent proxy-reported child dietary intake. A secondary objective was to compare intake estimates with those from national surveillance. Methods Parents of children aged 4–15 years participating in the TARGet Kids! research network in Toronto, Canada were invited by email to complete an online ASA24-Canada-2016 recall for their child, with a subsample prompted to complete a second recall about 2 weeks later. Descriptive statistics were reported for ASA24 completion characteristics and intake of several nutrients. Comparisons were made to the 2015 Canadian Community Health Survey (CCHS) 24-h recall data. Results A total of 163 parents completed the first recall, and 46 completed the second, reflecting response rates of 35% and 59%, respectively. Seven (4%) first recalls and one (2%) second recall were excluded for ineligibility, missing data, or inadvertent parental self-report. The median number of foods reported on the first recall was 18.0 (interquartile range (IQR) 6.0) and median time to complete was 29.5 min (IQR 17.0). Nutrient intakes for energy, total fat, protein, carbohydrates, fiber, sodium, total sugars, and added sugars were similar across the two recalls and the CCHS. Conclusions The ASA24 was found to be feasible for parent proxy-reporting of children’s intake and to yield intake estimates comparable to those from national surveillance, but strategies are needed to increase response rate and support completion to enhance generalizability.

Plain English Summary Including parents as partners in child health research can lead to choosing relevant research questions, recruiting children to participate who represent the general population, and sharing study results with communities. The structure of primary care offered to children presents an opportunity for building trusting relationships between families and clinicians, which may encourage parents and health care providers to participate in child health research. We provide an example of an ongoing study called TARGet Kids!, which includes children from birth to adolescence who attend regular health care visits. Researchers and clinicians have partnered with parents of children participating in TARGet Kids! to ensure child health research is centered on family values and preferences. A Parent And Clinician Team (PACT) was formed to set research priorities, design research studies together, troubleshoot issues, and communicate research findings back to health care providers, families, and policy makers. This partnership will lay a foundation for child health research which is practical, relevant to families and inclusive for improving children’s health care and public health policy.

Abstract Evidence generated from partnering with parents to design and conduct research together may be used to refine, adjust, and modify future research approaches. This study aimed to describe the initial approaches to parent engagement in the design of the PARENT trial as well as understand parent perspectives on the acceptability and relevance of the PARENT trial and potential barriers and facilitators to participation. Parents participating in the TARGet Kids! cohort were invited to participate in a focus group, called the PARENT panel, to co-design the PARENT trial. This focus group was conducted to capture diverse individual and collective parents’ experiences. Overall methodological approaches for the PARENT panel were informed by the CIHR Strategy for Patient Oriented Research (SPOR) guiding principles (mutual respect, co-building, inclusiveness, and support) for patient engagement in research, and facilitated through the Knowledge Translation Program in the Li Ka Shing Knowledge Institute at Unity Health Toronto. Using a Nominal Group Technique, the PARENT panel provided feedback on the feasibility, relevance, and acceptability of the proposed intervention. Findings from this work will be used to further refine, adjust, and modify the next iteration of the PARENT trial, which will also serve as an opportunity to discuss the efforts made by researchers to incorporate parent suggestions and what additional steps are required for improved patient engagement.

Abstract Objective To establish reference intervals for hemoglobin and mean corpuscular volume (MCV) in an ethnically diverse community sample of Canadian children 36 months and younger. Methods We collected blood samples from young children at scheduled primary care health supervision visits at 2 weeks, 2, 4, 6, 9, 12, 15, 18, 24, and 36 months of age. Samples were analyzed on the Sysmex XN-9000 Hematology Analyzer. We followed the Clinical and Laboratory Standards Institute guidelines in our analysis. Data were partitioned by sex and also combined. We considered large age partitions (3 and 6 months) as well as monthly partitions. Reference intervals (lower and upper limits) and 90% confidence intervals were calculated. Results Data from 2106 children were included. The age range was 2 weeks to 36 months, 46% were female, 48% were European and 23% were of mixed ethnicity. For hemoglobin, from 2 to 36 months of age, we found a wide reference interval and the 90% confidence intervals indicated little difference across age groups or according to sex. For MCV, from 2 to 7 months of age there was considerable decrease in the reference interval, which was lowest during the second year of life, followed by a slight increase in the last months of the third year of life. Conclusion These findings suggest adoption of a single hemoglobin reference interval for children 2–36 months of age. Further studies in children under 4 months of age are needed. Trial registration TARGet Kids! cohort is registered at ClinicalTrials.gov. www.clinicaltrials.gov . Identifier: NCT01869530 .

Abstract Background Household food insecurity (FI), even at marginal levels, is associated with poor child health outcomes. The Nutrition Screening Tool for Every Preschooler (NutriSTEP®) is a valid and reliable 17-item parent-completed measure of nutrition risk and includes a single item addressing FI which may be a useful child-specific screening tool. We evaluated the diagnostic test properties of the single NutriSTEP® FI question using the 2-item Hunger Vital Sign™ as the criterion measure in a primary care population of healthy children ages 18 months to 5 years. Results The sample included 1174 families, 53 (4.5%) of which were marginally food secure. An affirmative response to the single NutriSTEP® question “I have difficulty buying food I want to feed my child because food is expensive” had a sensitivity of 85% and specificity of 91% and demonstrated good construct validity when compared with the Hunger Vital Sign™. Conclusion The single NutriSTEP® question may be an effective screening tool in clinical practice to identify marginal food security in families with young children and to link families with community-based services or financial assistance programs including tax benefits. Trial registration TARGet Kids! practice-based research network (Registered June 5, 2013 at www.clinicaltrials.gov ; NCT01869530); www.targetkids.ca

In Ontario, Canada, school extracurricular activities and sports were modified or canceled for a prolonged period due to public health restrictions resulting from the COVID-19 pandemic. The present study aims to examine the association of changes to extracurricular and sport participation and child and youth mental health. Data were collected on child and youth mental health symptoms (n = 908) and participation in extracurricular activities and sports in the 2019–2020 and 2020–2021 academic years. Results indicated that pre-COVID (2019–2020) participation in either extracurricular activities or sports was associated with reduced anxiety, inattention, and hyperactivity during the pandemic (β range −0.08 to −0.11, p < 0.05). Participation in either extracurricular activities or sports during-COVID (2020–2021) was associated with lower depressive symptoms (β range −0.09 to −0.10, p < 0.05). Findings suggest that participation in extracurricular activities and/or school sports both before or during the COVID-19 pandemic were associated with better mental health outcomes in children and youth. Implications of this work consider future situations where restrictions on extracurricular and sport participation are reinstated and the impact of child and youth mental health.

Abstract Background Although research on the relationship between parent and child mental health is growing, the impact of early parenting stress on preschool-aged children’s mental health remains unclear. The objective was to evaluate the association between parenting stress during infancy and mental health problems in 3-year-old children. Methods A prospective cohort study of healthy preschool-aged children recruited from 9 primary care practices in Toronto, Canada was conducted through the TARGet Kids! primary care practice-based research network. Parenting stress was measured when children were between 0 to 16 months of age, using the Parent Stress Index Short Form, PSI-SF. Parent-reported child mental health problems were measured at 36 to 47 months using the preschool Strengths and Difficulties Questionnaire, total difficulties score (TDS). Hierarchical linear regression analysis was used to investigate the association between standardized PSI-SF and TDS, adjusted for child age, sex, temperament, sleep duration and household income. To strengthen clinical interpretation, analysis was repeated using adjusted multivariable logistic regression (TDS dichotomized at top 20%). Results A total of 148 children (mean ± SD age, 37.2 ± 1.7 months, 49% male) were included in the analysis. Parenting stress during infancy (11.4 ± 3.1 months of age) was significantly associated with mental health problems in 3-year-old children (β = 0.35; 95% CI = 0.20–0.49, p

Summary Objective Identifying how obesity‐related characteristics cluster in populations is important to understand disease risk. Objectives of this study were to identify classes of children based on obesity‐related variables and to evaluate the associations between the identified classes and overweight and obesity. Methods A cross‐sectional study was conducted among children 3–11 years of age (n = 5185) from the TARGet Kids! network (2008–2018). Latent class analysis was used to identify distinct classes of children based on 15 family, metabolic, health behaviours and school‐related variables. Associations between the identified latent classes and overweight and obesity were estimated using multinomial logistic regression. Results Six classes were identified: Class 1: ‘Family and health risk behaviours’ (20%), Class 2: ‘Metabolic risk’ (7%), Class 3: ‘High risk’ (6%), Class 4: ‘High triglycerides’ (21%), Class 5: ‘Health risk behaviours and developmental concern’ (22%), and Class 6: ‘Healthy’ (24%). Children in Classes 1–5 had increased odds of both overweight and obesity compared with ‘Healthy’ class. Class 3 'High risk' was most strongly associated with child overweight (odds ratio [OR] 1.9, 95% confidence interval [CI] 1.2, 3.2) and obesity (OR 3.3, 95% CI 1.7, 6.7). Conclusions Distinct classes of children identified based on obesity‐related characteristics were all associated with increased obesity; however, the magnitude of risk varied depending on number of at‐risk characteristics. Understanding the clustering of obesity characteristics in children may inform precision public health and population prevention interventions.

Abstract Background Children and youth who meet the physical activity, sedentary, and sleep behaviour recommendations in the Canadian 24-Hour Movement Guidelines are more likely to have desirable physical and psychosocial health outcomes. Yet, few children and youth actually meet the recommendations. The family is a key source of influence that can affect lifestyle behaviours. The purpose of this paper is to describe the process used to develop the Consensus Statement on the Role of the Family in the Physical Activity, Sedentary, and Sleep Behaviours of Children and Youth (0–17 years) and present, explain, substantiate, and discuss the final Consensus Statement. Methods The development of the Consensus Statement included the establishment of a multidisciplinary Expert Panel, completion of six reviews (three literature, two scoping, one systematic review of reviews), custom data analyses of Statistics Canada’s Canadian Health Measures Survey, integration of related research identified by Expert Panel members, a stakeholder consultation, establishment of consensus, and the development of a media, public relations, communications and launch plan. Results Evidence from the literature reviews provided substantial support for the importance of family on children’s movement behaviours and highlighted the importance of inclusion of the entire family system as a source of influence and promotion of healthy child and youth movement behaviours. The Expert Panel incorporated the collective evidence from all reviews, the custom analyses, other related research identified, and stakeholder survey feedback, to develop a conceptual model and arrive at the Consensus Statement: Families can support children and youth in achieving healthy physical activity, sedentary and sleep behaviours by encouraging, facilitating, modelling, setting expectations and engaging in healthy movement behaviours with them. Other sources of influence are important (e.g., child care, school, health care, community, governments) and can support families in this pursuit. Conclusion Family is important for the support and promotion of healthy movement behaviours of children and youth. This Consensus Statement serves as a comprehensive, credible, and current synopsis of related evidence, recommendations, and resources for multiple stakeholders.

Abstract Background Observational longitudinal data often feature irregular, informative visit times. We propose descriptive measures to quantify the extent of irregularity to select an appropriate analytic outcome approach. Methods We divided the study period into bins and calculated the mean proportions of individuals with 0, 1, and > 1 visits per bin. Perfect repeated measures features everyone with 1 visit per bin. Missingness leads to individuals with 0 visits per bin while irregularity leads to individuals with > 1 visit per bin. We applied these methods to: 1) the TARGet Kids! study, which invites participation at ages 2, 4, 6, 9, 12, 15, 18, 24 months, and 2) the childhood-onset Systemic Lupus Erythematosus (cSLE) study which recommended at least 1 visit every 6 months. Results The mean proportions of 0 and > 1 visits per bin were above 0.67 and below 0.03 respectively in the TARGet Kids! study, suggesting repeated measures with missingness. For the cSLE study, bin widths of 6 months yielded mean proportions of 1 and > 1 visits per bin of 0.39, suggesting irregular visits. Conclusions Our methods describe the extent of irregularity and help distinguish between protocol-driven visits and irregular visits. This is an important step in choosing an analytic strategy for the outcome.

Abstract Objectives While studies exist on the association between screen time and cardiometabolic risk among adolescents, research examining the effect of screen time on cardiometabolic risk in young children is lacking. The primary objective of this study was to examine the association between daily screen time and cardiometabolic risk (CMR) [sum of age- and sex-standardized z-scores of systolic blood pressure (SBP), glucose, log-triglycerides, waist circumference (WC), and negative high-density lipoprotein (HDL) cholesterol divided by the square root of five] in young children. Secondary objectives included examining individual CMR risk factors, including waist-to-height ratio and non high-density lipoprotein (non-HDL) cholesterol, as well as the individual cut-offs of these risk factors. Additional analyses include examining the association between screen time and CMR by handheld/non-handheld devices. Methods A study was conducted among young children 3 to 6 years from the TARGet Kids! practice-based research network in Toronto and Montreal, Canada. Children with one or more measures of screen time and CMR were included in this study. Generalized estimating equation (GEE) multivariable linear regressions and multivariable logistic regressions, using published cut-offs, were conducted to evaluate these associations. Results Data from 1317 children [mean age 52 months (SD = 13.36), 44.34% female] were included for analyses. There was no evidence of associations between screen time and total CMR score or individual risk factors (p > 0.05) after adjusting for confounders. A statistically significant, but small association between daily screen time and non-HDL cholesterol was found (B = 0.046; CI = [0.017 to 0.075]; p = 0.002. Conclusions Though no relationship was reported between daily screen time and the majority of CMR factors in early childhood, there was an association between daily screen time and non-HDL cholesterol. As the relationship between daily screen time and CMR factors may not be apparent in early childhood, studies to evaluate longer-term cardiometabolic effects of screen time are needed. Although there is an evidence-based rationale to reduce screen time in early childhood, prevention of cardiometabolic risk may not be the primary driver.

Introduction The COVID-19 pandemic has impacted the mental health (MH) of children, adolescents and parents. Whereas youth with MH disorders and neurodevelopmental disorders (NDD) may be at higher risk for exacerbations in emotional and behavioural distress, children and adolescents without pre-existing MH disorders or NDD may also experience MH deterioration due to increases in stress, changes in health behaviours, loss of activities/school closures or loss of resources. Little is known about the impact of the COVID-19 emergency measures (EMs) on children’s MH over the course of the pandemic.Methods and analysis Longitudinal study of four well-established, pre-existing cohorts in Ontario (two recruited in clinical settings, two recruited in community settings). Primary outcomes include the impact of EMs on six MH domains: depression, anxiety, irritability, inattention, hyperactivity and obsessive–compulsive behaviours. Risk and protective factors related to youth MH profiles and trajectories will be identified. In addition, the effects of school mitigation strategies, changes in MH services and family factors (ie, parental MH, economic deprivation and family functioning) on children’s MH will be examined. Data will be collected via repeated online survey measures selected to ensure reliability and validity for the proposed populations and distributed through the pandemic periods.Ethics and dissemination The study was approved by institutional research ethics boards at participating research sites. Results will be disseminated through a robust knowledge translation partnership with key knowledge users. Materials to inform public awareness will be co-developed with educators, public health, and MH and health service providers. Connections with professional associations and MH advocacy groups will be leveraged to support youth MH policy in relation to EMs. Findings will further be shared through conference presentations, peer-reviewed journals and open-access publications.

ObjectivesTo establish the factorial structure and internal consistency of the Internet Addiction Test (IAT) in parents, the level and correlates of problematic internet use, and patterns and types of screen use.Study designData were collected through an online questionnaire about preconception health among Canadian women and men with ≥1 child. The questionnaire included the IAT and questions about time spent on screens by device type, use of screens during meals and in the bedroom, and perceptions of overuse. Factor analysis was completed to determine the factorial structure of the IAT, with multivariable linear regression used to determine correlates of the IAT.ResultsThe sample included 1,156 respondents (mean age: 34.3 years; 83.1% female). The IAT had two factors: "impairment in time management" and "impairment in socio-emotional functioning" of which respondents had more impairment in time management than socio-emotional functioning. Based on the original IAT, 19.4% of respondents would be classified as having a mild internet use problem with 3.0% having a moderate or severe issue. In the multivariable model, perceived stress (b = .28, SE = .05, p < .001) and depressive symptoms (b = .24, SE = .10, p = .017) were associated with higher IAT scores. Handheld mobile devices were the most common type of screen used (mean = 3 hours/day) followed by watching television (mean = 2 hours/day).ConclusionParents spent a significant portion of their time each day using screens, particularly handheld mobile devices. The disruption caused by mobile devices may hinder opportunities for positive parent-child interactions, demonstrating the need for resources to support parents ever-growing use of technologies.

Abstract Background The COVID-19 pandemic has uniquely affected children and families by disrupting routines, changing relationships and roles, and altering usual child care, school and recreational activities. Understanding the way families experience these changes from parents’ perspectives may help to guide research on the effects of COVID-19 among children. Main body As a multidisciplinary team of child health researchers, we assembled a group of nine parents to identify concerns, raise questions, and voice perspectives to inform COVID-19 research for children and families. Parents provided a range of insightful perspectives, ideas for research questions, and reflections on their experiences during the pandemic. Conclusion Including parents as partners in early stages of COVID-19 research helped determine priorities, led to more feasible data collection methods, and hopefully has improved the relevance, applicability and value of research findings to parents and children.

Abstract Background Measuring body mass index (BMI) has been proposed as a method of screening for preventive primary care and population surveillance of childhood obesity. However, the accuracy of routinely collected measurements has been questioned. The purpose of this study was to assess the reliability of height, length and weight measurements collected during well-child visits in primary care relative to trained research personnel. Methods A cross-sectional study of measurement reliability was conducted in community pediatric and family medicine primary care practices. Each participating child, ages 0 to 18 years, was measured four consecutive times; twice by a primary care team member (e.g. nurses, practice personnel) and twice by a trained research assistant. Inter- and intra-observer reliability was calculated using the technical error of measurement (TEM), relative TEM (%TEM), and a coefficient of reliability (R). Results Six trained research assistants and 16 primary care team members performed measurements in three practices. All %TEM values for intra-observer reliability of length, height, and weight were classified as ‘acceptable’ ( 99% for both intra- and inter-observer reliability. Length measurements in children

Aim: To examine CVD risk factors among children and adolescents with Major Depressive Disorder (MDD).Methods: A cross-sectional study of 77 children and adolescents (mean age 14.1 years, 74% female) referred to a pediatric depression program. MDD was assessed using a semi-structured diagnostic interview. Cardiovascular assessments included family cardiovascular disease (CVD) history, cigarette smoking, body mass index (BMI), blood pressure, lipid and glucose concentrations. CVD risk factors among healthy weight and overweight/obese participants were compared.Results: Forty-six percent of participants had a family history of early CVD. On examination, 25% of participants had a BMI in overweight/obese range, and 25% of children had pre-hypertension (14%) or hypertension (11%). Total cholesterol levels were elevated among 28% of participants. Overweight/obese participants had increased non-HDL cholesterol concentrations compared with healthy-weight participants (36 vs. 10%, p = 0.01). There were no significant differences between healthy and overweight/obese groups for other CVD risk factors, including HDL cholesterol concentration, plasma glucose concentration, hypertension, cigarette smoking, and family history of early CVD. More than half (52%) of participants had at least two CVD risk factors.Conclusion: CVD risk factors are prevalent among children and adolescents with MDD. Routine CVD risk factor screening may be warranted among MDD youth, regardless of BMI, and may provide a valuable opportunity for prevention of future CVD.

Introduction School readiness is a multidimensional construct that includes cognitive, behavioural and emotional aspects of a child’s development. School readiness is strongly associated with a child’s future school success and well-being. The Early Development Instrument (EDI) is a reliable and valid teacher-completed tool for assessing school readiness in children at kindergarten age. A substantial knowledge gap exists in understanding how early child growth, health behaviours, nutrition, cardiometabolic risk and development impact school readiness. The primary objective was to determine if growth patterns, measured by body mass index trajectories in healthy children aged 0–5 years, are associated with school readiness at ages 4–6 years (kindergarten age). Secondary objectives were to determine if other health trajectories, including health behaviours, nutrition, cardiometabolic risk and development, are associated with school readiness at ages 4–6 years. This paper presents the Fit for School Study protocol.Methods and analysis This is an ongoing prospective cohort study. Parents of children enrolled in the The Applied Health Research Group for Kids (TARGet Kids!) practice-based research network are invited to participate in the Fit for School Study. Child growth, health behaviours, nutrition, cardiometabolic risk and development data are collected annually at health supervision visits and linked to EDI data collected by schools. The primary and secondary analyses will use a two-stage process: (1) latent class growth models will be used to first determine trajectory groups, and (2) generalised linear mixed models will be used to examine the relationship between exposures and EDI results.Ethics and dissemination The research ethics boards at The Hospital for Sick Children, Unity Health Toronto and McMaster University approved this study, and research ethics approval was obtained from each school board with a student participating in the study. The findings will be presented locally, nationally and internationally and will be published in peer-reviewed journals.Trial registration number NCT01869530.

Screen use has become a pervasive behaviour among children and has been linked to adverse health outcomes. The objective of this study was to examine the association between screen time and a comprehensive total cardiometabolic risk (CMR) score in school-aged children (7–12-years), as well as individual CMR factors. In this longitudinal study, screen time was measured over time (average duration of follow-up was 17.4 months) via parent-report. Anthropometric measurements, blood pressure, and biospecimens were collected over time and used to calculate CMR score [sum of age and sex standardized z-scores of systolic blood pressure (SBP), glucose, log-triglycerides, waist circumference (WC), and negative high-density lipoprotein cholesterol (HDL-c)/square-root of 5]. Generalized estimating equations (GEE) were used to examine the association between screen time and total CMR score as well as individual CMR factors. A total of 567 children with repeated measures were included. There was no evidence of an association between parent-reported child screen time and total CMR score (adjusted β = −0.01, 95% CI [−0.03, 0.005], 0.16). Screen time was inversely associated HDL-c (adjusted β = −0.008, 95% CI [−0.011, −0.005], p = 0.016), but there was no evidence that the other CMR components were associated with screen time. Among children 7–12 years, there was no evidence of an association between parent-reported child screen time and total CMR, but increased screen time was associated with slightly lower HDL-c. Research is needed to understand screen-related contextual factors which may be related to CMR factors.

Objective: Sugar-containing beverages (SCBs) including 100% fruit juice, fruit drinks and soda substantially contribute to total caloric intake in young children. The objective of this study was to examine whether consumption of SCB is associated with cardiometabolic risk (CMR) in preschool children, along with whether 100% fruit juice and sugar sweetened beverage (SSB) is associated with CMR. Study Design: We used a repeated measures study design examining SCB consumption and CMR outcomes measured concurrently in children 3–6 years of age participating in TARGet Kids!, a primary-care, practice-based research network in Canada (2008–2017). To account for within-person variability, multivariable linear regression models using generalized estimating equation was used to examine the association between SCB consumption and CMR score and the individual CMR score components including systolic blood pressure, waist circumference, high-density lipoprotein cholesterol (HDL-c), triglycerides, and glucose. Results: After adjusting for sociodemographic, familial and child-related covariates, higher SCB consumption was associated with elevated CMR score [0.05 (95% CI −0.0001 to 0.09), p = 0.05], including lower HDL-c [−0.02 mmol/L (95% CI −0.03 to −0.01), p = 0.01] and higher triglycerides [0.02 mmol/L (95% CI 0.004 to 0.04), p = 0.02]. When examined separately, higher 100% fruit juice [−0.02 mmol/L (95% CI −0.03 to −0.003), p = 0.02] and SSB[-0.03 mmol/L (95% CI −0.06 to −0.001), p = 0.04] consumption were each associated with lower HDL-c. Conclusion: Higher SCB consumption was associated with small elevations of CMR in preschool children. Our findings support recommendations to limit overall intake of SCBs in early childhood, in effort to reduce the potential long-term burden of CMR. Keywords: Sugar-sweetened beverages, 100% fruit juice, HDL-cholesterol, Triglycerides

Abstract Background Iron deficiency in early childhood has been associated with poor developmental outcomes. Little is known about the nutritional health of young children receiving care at Canadian Community Health Centres (CHCs). Our objectives were to describe iron deficiency among toddlers at an Ontario CHC, to compare young children attending CHCs and non-CHCs, and assess the feasibility of conducting research on children in CHC settings. Methods One CHC, Kingston Community Health Centres (CHC) with two clinical sites and one community programming site was added to the nine non-CHC pediatric and primary care clinics in the existing TARGet Kids! research network. A cross-sectional feasibilitystudy was conducted.and. Healthy children, ages 12–36 months were Enrolled. iron deficiency without inflammation (ferritin

Abstract Background The objective of this systematic review was to examine for the first time the associations between sleep duration and a broad range of health indicators in children aged 0 to 4 years. Methods Electronic databases were searched with no limits on date or study design. Included studies (published in English or French) were peer-reviewed and met the a priori determined population (apparently healthy children aged 1 month to 4.99 years), intervention/exposure/comparator (various sleep durations), and outcome criteria (adiposity, emotional regulation, cognitive development, motor development, growth, cardiometabolic health, sedentary behaviour, physical activity, quality of life/well-being, and risks/injuries). The quality of evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) framework. Due to high levels of heterogeneity across studies, narrative syntheses were employed. Results A total of 69 articles/studies (62 unique samples) met inclusion criteria. Data across studies included 148,524 unique participants from 23 countries. The study designs were randomized trials (n = 3), non-randomized interventions (n = 1), longitudinal studies (n = 16), cross-sectional studies (n = 42), or longitudinal studies that also reported cross-sectional analyses (n = 7). Sleep duration was assessed by parental report in 70% of studies (n = 48) and was measured objectively (or both objectively and subjectively) in 30% of studies (n = 21). Overall, shorter sleep duration was associated with higher adiposity (20/31 studies), poorer emotional regulation (13/25 studies), impaired growth (2/2 studies), more screen time (5/5 studies), and higher risk of injuries (2/3 studies). The evidence related to cognitive development, motor development, physical activity, and quality of life/well-being was less clear, with no indicator showing consistent associations. No studies examined the association between sleep duration and cardiometabolic biomarkers in children aged 0 to 4 years. The quality of evidence ranged from “very low” to “high” across study designs and health indicators. Conclusions Despite important limitations in the available evidence, longer sleep duration was generally associated with better body composition, emotional regulation, and growth in children aged 0 to 4 years. Shorter sleep duration was also associated with longer screen time use and more injuries. Better-quality studies with stronger research designs that can provide information on dose-response relationships are needed to inform contemporary sleep duration recommendations.

Abstract Objective To evaluate the misclassification resulting from the use of body mass index (BMI) cut-points defined by rounded percentiles instead of Z-scores in early childhood. Using data from the TARGet Kids primary care network we conducted a cross-sectional study among 5836 children 1.0, > 2.0, > 3.0 are recommended to define wasted, at risk of overweight, overweight and obese. However, rounded percentiles of the 3rd, 85th, 97th, and 99.9th are commonly used. Misclassification was calculated comparing the frequency distributions for BMI categories defined by rounded percentiles and Z-score cut-points. Results Using rounded percentiles, the proportion of children who were wasted, at risk of overweight, overweight, and obese was 4.2, 12.5, 4.3 and 0.8%, whereas the distribution using Z-scores was: 3.6, 13.8, 3.4 and 1.0%, respectively. Overall, 117 (2%) children were misclassified when using percentiles instead of Z-scores; however, 13% (33/245) of children who were wasted and 14% (8/57) of children who were obese were misclassified. Misclassification of child growth results from the use of cut-points defined by rounded percentiles instead of Z-scores and limits comparability between studies. Trial registration Clinicaltrials.gov NCT01869530 June 5, 2013