Underweight in the first 2 years of life and nutrition risk in later childhood: a prospective cohort study

BACKGROUND

Children with underweight in the first 2 years have lower body mass index z-score (zBMI) and height-for-age z-score (HAZ) in later childhood. It is not known if underweight in the first 2 years is associated with nutrition risk in later childhood.

OBJECTIVE

(1) Determine the relationship between underweight (zBMI < -2) in the first 2 years and nutrition risk measured by the Nutrition Screening for Toddlers and Preschoolers (NutriSTEP) score from 18 months to 5 years. (2) Explore the relationship between underweight in the first 2 years and the NutriSTEP subscores for eating behaviours and dietary intake from 18 months to 5 years.

METHODS

This was a prospective study, including healthy full-term children in Canada aged 0-5 years. zBMI was calculated using measured heights and weights and the WHO growth standards. NutriSTEP score was measured using a parent-completed survey and ranged from 0 to 68. Nutrition risk was defined as a score ≥21. Linear mixed effects models were used.

RESULTS

Four thousand nine hundred twenty-nine children were included in this study. At enrolment, 51.9% of participants were male. The prevalence of underweight children was 8.8%. Underweight in the first 2 years was associated with higher NutriSTEP (0.79, 95% CI: 0.29,1.29), higher eating behaviour subscore (0.24, 95% CI: 0.03, 0.46) at 3 years and higher odds of nutrition risk (OR: 1.39, 95% CI: 1.07,1.82) at 5 years.

CONCLUSIONS

Children with underweight in the first 2 years had higher nutrition risk in later childhood. Further research is needed to understand the factors which influence these relationships.

Haemoglobin thresholds to define anaemia from age 6 months to 65 years: estimates from international data sources

BACKGROUND

Detection of anaemia is crucial for clinical medicine and public health. Current WHO anaemia definitions are based on statistical thresholds (fifth centiles) set more than 50 years ago. We sought to establish evidence for the statistical haemoglobin thresholds for anaemia that can be applied globally and inform WHO and clinical guidelines.

METHODS

In this analysis we identified international data sources from populations in the USA, England, Australia, China, the Netherlands, Canada, Ecuador, and Bangladesh with sufficient clinical and laboratory information collected between 1998 and 2020 to obtain a healthy reference sample. Individuals with clinical or biochemical evidence of a condition that could reduce haemoglobin concentrations were excluded. We estimated haemoglobin thresholds (ie, 5th centiles) for children aged 6-23 months, 24-59 months, 5-11 years, and 12-17 years, and adults aged 18-65 years (including during pregnancy) for individual datasets and pooled across data sources. We also collated findings from three large-scale genetic studies to summarise genetic variants affecting haemoglobin concentrations in different ancestral populations.

FINDINGS

We identified eight data sources comprising 18 individual datasets that were eligible for inclusion in the analysis. In pooled analyses, the haemoglobin fifth centile was 104·4 g/L (90% CI 103·5-105·3) in 924 children aged 6-23 months, 110·2 g/L (109·5-110·9) in 1874 children aged 24-59 months, and 114·4 g/L (113·6-115·2) in 1839 children aged 5-11 years. Values diverged by sex in adolescents and adults. In pooled analyses, the fifth centile was 122·2 g/L (90% CI 121·3-123·1) in 1741 female adolescents aged 12-17 years and 128·2 g/L (126·4-130·0) in 1103 male adolescents aged 12-17 years. In pooled analyses of adults aged 18-65 years, the fifth centile was 119·7 g/L (90% CI 119·1-120·3) in 3640 non-pregnant females and 134·9 g/L (134·2-135·6) in 2377 males. Fifth centiles in pregnancy were 110·3 g/L (90% CI 109·5-111·0) in the first trimester (n=772) and 105·9 g/L (104·0-107·7) in the second trimester (n=111), with insufficient data for analysis in the third trimester. There were insufficient data for adults older than 65 years. We did not identify ancestry-specific high prevalence of non-clinically relevant genetic variants that influence haemoglobin concentrations.

INTERPRETATION

Our results enable global harmonisation of clinical and public health haemoglobin thresholds for diagnosis of anaemia. Haemoglobin thresholds are similar between sexes until adolescence, after which males have higher thresholds than females. We did not find any evidence that thresholds should differ between people of differering ancestries.

FUNDING

World Health Organization and the Bill & Melinda Gates Foundation.

Association of factors with childhood asthma and allergic diseases using latent class analysis

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.

Randomised trials conducted using cohorts: a scoping review

INTRODUCTION

Cohort studies generate and collect longitudinal data for a variety of research purposes. Randomised controlled trials (RCTs) increasingly use cohort studies as data infrastructures to help identify and recruit trial participants and assess outcomes.

OBJECTIVE

To examine the extent, range and nature of research using cohorts for RCTs and describe the varied definitions and conceptual boundaries for RCTs using cohorts.

DESIGN

Scoping review.

DATA SOURCES

Searches were undertaken in January 2021 in MEDLINE (Ovid) and EBM Reviews-Cochrane Methodology Registry (Final issue, third Quarter 2012).

ELIGIBILITY CRITERIA

Reports published between January 2007 and December 2021 of (a) cohorts used or planned to be used, to conduct RCTs, or (b) RCTs which use cohorts to recruit participants and/or collect trial outcomes, or (c) methodological studies discussing the use of cohorts for RCTs.

DATA EXTRACTION AND SYNTHESIS

Data were extracted on the condition being studied, age group, setting, country/continent, intervention(s) and comparators planned or received, unit of randomisation, timing of randomisation, approach to informed consent, study design and terminology.

RESULTS

A total of 175 full-text articles were assessed for eligibility. We identified 61 protocols, 9 descriptions of stand-alone cohorts intended to be used for future RCTs, 39 RCTs using cohorts and 34 methodological papers.The use and scope of this approach is growing. The thematics of study are far-ranging, including population health, oncology, mental and behavioural disorders, and musculoskeletal conditions.Authors reported that this approach can lead to more efficient recruitment, more representative samples, and lessen disappointment bias and crossovers.

CONCLUSION

This review outlines the development of cohorts to conduct RCTs including the range of use and innovative changes and adaptations. Inconsistencies in the use of terminology and concepts are highlighted. Guidance now needs to be developed to support the design and reporting of RCTs conducted using cohorts.

The mediation effect of breastfeeding duration on the relationship between maternal preconception BMI and childhood nutritional risk

BACKGROUND

Higher maternal preconception body mass index (BMI) is associated with lower breastfeeding duration, which may contribute to the development of poor child eating behaviours and dietary intake patterns (components of nutritional risk). A higher maternal preconception BMI has been found to be associated with higher child nutritional risk. This study aimed to determine whether breastfeeding duration mediated the association between maternal preconception BMI and child nutritional risk.

METHODS

In this longitudinal cohort study, children ages 18 months to 5 years were recruited from The Applied Research Group for Kids (TARGet Kids!) in Canada. The primary outcome was child nutritional risk, using The NutriSTEP®, a validated, parent-reported questionnaire. Statistical mediation analysis was performed to assess whether total duration of any breastfeeding mediated the association between maternal preconception BMI and child nutritional risk.

RESULTS

This study included 4733 children with 8611 NutriSTEP® observations. The mean (SD) maternal preconception BMI was 23.6 (4.4) and the mean (SD) breastfeeding duration was 12.4 (8.0) months. Each 1-unit higher maternal preconception BMI was associated with a 0.081 unit higher nutritional risk (95% CI (0.051, 0.112); p < 0.001) (total effect), where 0.011(95% CI (0.006, 0.016); p < 0.001) of that total effect or 13.18% (95% CI: 7.13, 21.25) was mediated through breastfeeding duration.

CONCLUSION

Total breastfeeding duration showed to mediate part of the association between maternal preconception BMI and child nutritional risk. Interventions to support breastfeeding in those with higher maternal preconception BMI should be evaluated for their potential effect in reducing nutritional risk in young children.

Plant-Based Milk Consumption and Growth in Children 1-10 Years of Age

BACKGROUND

The effects of plant-based milk consumption on the growth of children are unclear.

OBJECTIVES

We aimed to evaluate the relationship between plant-based milk consumption and BMI in childhood. Secondary objectives were to examine the association with height and whether these relationships are mediated by dairy milk intake and modified by age or the type of plant-based milk consumed.

METHODS

A prospective cohort study was conducted in healthy children aged 1-10 y through the TARGet Kids! primary care research network in Toronto, Canada. Linear mixed-effect modeling and logistic generalized estimating equations were used to evaluate the association between plant-based milk consumption (number of 250 mL cups/d) and BMI. A mediation analysis was conducted to examine whether dairy milk intake mediated these relationships. Effect modification by age and type of plant-based milk was explored.

RESULTS

Among 7195 children (mean age: 3.1 y; 52.3% male), higher plant-based milk consumption was associated with lower BMI (P = 0.0002) and height (P = 0.005). No association was found with BMI categories. Lower dairy milk intake partially mediated these relationships. A child aged 5 y who consumed 3 cups of plant-based milk compared with 3 cups of dairy milk had a lower weight of 0.5 kg and lower height of 0.8 cm. Associations did not change over time and were similar for children who consumed soy milk compared with other plant-based milks.

CONCLUSIONS

Plant-based milk consumption was associated with lower BMI and height, but both were within the normal range on average. Future longitudinal studies are needed to determine whether these associations persist over time.

Factors associated with COVID-19 vaccination in young children

OBJECTIVE

To examine factors associated with COVID-19 vaccination (time to vaccination and vaccination status) among healthy young children participating in primary healthcare.

METHODS

A cohort study was conducted between November 2021 and September 2022 through the TARGet Kids! primary care research network in Toronto, Canada. Sociodemographic information, child and parent health characteristics, parental vaccine beliefs and child COVID-19 vaccine uptake were collected through parent-reported questionnaires. The primary outcome was time to child COVID-19 vaccination, measured as the time between vaccine availability date and parent-reported child COVID-19 vaccination date. Interval-censored proportional hazard models were used.

RESULTS

A total of 267 children age 0 to 13 years were included. The mean child age was 7.6 years, 52.8% (n = 141) were male, 66.5% (n = 141) had mothers of European ethnicity (with missingness), and 68.2% (n = 182) of the children were vaccinated. All parents of vaccinated children had received the COVID-19 vaccination themselves. The rate of vaccination for children was 2% higher with each one-month increase in child age (adjusted HR = 1.02, 95%CI = 1.01-1.03, p < 0.001). Compared to children whose parents had uncertain beliefs, those whose parents had positive beliefs about the importance and safety of COVID-19 vaccination for their children had higher rates of vaccination (adjusted HR = 8.29, 95%CI = 4.25-16.17, p < 0.001; adjusted HR = 5.09, 95%CI = 3.17-8.17, p < 0.001).

CONCLUSION

Older child age, parental COVID-19 vaccination, and positive parental beliefs about COVID-19 vaccination were statistically significantly associated with COVID-19 vaccination among healthy young children. Our findings may help to inform policies, practices, and research which aim to strengthen parental vaccine confidence and promote child COVID-19 vaccination.

Xylitol for the prevention of acute otitis media episodes in children aged 1-5 years: a randomised controlled trial

OBJECTIVE

To investigate the regular use of xylitol, compared with sorbitol, to prevent acute otitis media (AOM), upper respiratory tract infections (URTIs) and dental caries.

DESIGN

Blinded randomised controlled trial with a 6-month study period.

SETTING

Enrolment took place at 11 primary care practices in Ontario, Canada.

PATIENTS

Children aged 1-5 years who did not use xylitol or sorbitol at enrolment.

INTERVENTIONS

Children were randomly assigned to use a placebo syrup with sorbitol or xylitol syrup two times per day for 6 months.

MAIN OUTCOME MEASURES

Primary outcome was the number of clinician-diagnosed AOM episodes over 6 months. Secondary outcomes were caregiver-reported URTIs and dental caries.

RESULTS

Among the 250 randomised children, the mean (SD) age was 38±14 months and there were 124 girls (50%). There were three clinician-diagnosed AOM episodes in the 125 placebo group participants and six in the 125 xylitol group participants (OR 2.04; 95% CI 0.43, 12.92; p=0.50). There was no difference in number of caregiver-reported URTI episodes (rate ratio (RR) 0.88; 95% CI 0.70, 1.11) between the placebo (4.2 per participant over 6 months; 95% CI 3.6, 5.0) and xylitol (3.7; 95% CI 3.2, 4.4) groups. Dental caries were reported for four participants in the placebo group and two in the xylitol group (OR 0.42; 95% CI 0.04, 3.05; p=0.42). In a post-hoc analysis of URTIs during the COVID-19 pandemic, the rate among the 59 participants receiving placebo was 2.3 per participant over 6 months (95% CI 1.8, 3.0) and for the 55 receiving xylitol, 1.3 over 6 months (95% CI 0.92, 1.82; RR 0.56; 95% CI 0.36, 0.87). The most common adverse event was diarrhoea (28% with placebo; 34% with xylitol).

CONCLUSIONS

Regular use of xylitol did not prevent AOM, URTIs or dental caries in a trial with limited statistical power. A post-hoc analysis indicated that URTIs were less common with xylitol exposure during the COVID-19 pandemic, but this finding could be spurious.

TRIAL REGISTRATION NUMBER

NCT03055091.

Association Between Family Income and Positive Developmental Screening Using the Infant Toddler Checklist at the 18-Month Health Supervision Visit

OBJECTIVE

To examine the associations between several potential predictors (child biologic, social, and family factors) and a positive screen for developmental delay using the Infant Toddler Checklist (ITC) at the 18-month health supervision visit in primary care.

METHODS

This was a cross-sectional study of healthy children attending an 18-month health supervision visit in primary care. Parents completed a standardized questionnaire, addressing child, social, and family characteristics, and the ITC. Logistic regression analyses were used to assess the associations between predictors and a positive ITC.

RESULTS

Among 2188 participants (45.5% female; mean age, 18.2 months), 285 (13%) had a positive ITC and 1903 (87%) had a negative ITC. The aOR for a positive ITC for male compared with female sex was 2.15 (95% CI, 1.63-2.83; P < .001). The aOR for birthweight was 0.65 per 1 kg increase (95% CI, 0.53-0.80; P < .001). The aOR for a family income of <$40,000 compared with ≥$150,000 was 3.50 (95% CI, 2.22-5.53; P < .001), and the aOR for family income between $40,000-$79,999 compared with ≥$150,000 was 1.88 (95% CI, 1.26-2.80; P = .002).

CONCLUSIONS

Screening positive on the ITC may identify children at risk for the double jeopardy of developmental delay and social disadvantage and allow clinicians to intervene through monitoring, referral, and resource navigation for both child development and social needs.

TRIAL REGISTRATION

Clinicaltrials.gov (NCT01869530).

Determinants of Anishinabeck infant and early childhood growth trajectories in Northwestern Ontario, Canada: a cohort study

BACKGROUND

The Developmental Origins of Health and Disease (DOHaD) paradigm emphasizes the significance of early life factors for the prevention of chronic health conditions, like type 2 diabetes (T2DM) and obesity, which disproportionately affect First Nations communities in Canada. Despite increasing DOHaD research related to maternal health during pregnancy, early childhood growth patterns, and infant feeding practices with many populations, data from First Nations communities in Canada are limited. In partnership with Sandy Lake First Nation, the aims of this project were to characterize birthweights and growth patterns of First Nations infants/children over the first 6 years of life and to study the impact of maternal and infant social and behavioral factors on birthweight and growth trajectories.

METHODS

We recruited 194 families through community announcements and clinic visits. Infant/child length/height and weight were measured at 1 and 2 weeks; 1, 2, 6, 12, and 18 months; and 2, 3, 4, 5 and 6 years. Maternal and infant/child questionnaires captured data about health, nutrition, and social support. Weight-for-Age z-score (WAZ), Height-for-Age z-score (HAZ), and BMI-for-Age z-score (BAZ) were calculated using WHO reference standards and trajectories were analyzed using generalized additive models. Generalized estimating equations and logistic regression were used to determine associations between exposures and outcomes.

RESULTS

WAZ and BAZ were above the WHO mean and increased with age until age 6 years. Generalized estimating equations indicated that WAZ was positively associated with age (0.152; 95% CI 0.014, 0.29), HAZ was positively associated with birthweight (0.155; 95% CI 0.035, 0.275), and BAZ was positively associated with caregiver's BMI (0.049; 95% CI 0.004, 0.090). There was an increased odds of rapid weight gain (RWG) with exposure to gestational diabetes (OR: 7.47, 95% CI 1.68, 46.22). Almost 70% of parents initiated breastfeeding, and breastfeeding initiation was modestly associated with lower WAZ (-0.18; 95% CI -0.64, 0.28) and BAZ (-0.23; 95% CI -0.79, 0.34).

CONCLUSIONS

This work highlights early life factors that may contribute to T2DM etiology and can be used to support community and Indigenous-led prevention strategies.

Association of birthweight with diabetes, hypertension, and ischemic heart disease in young adulthood: a retrospective cohort study

Birthweight has been associated with diabetes in a reverse J-shape (highest risk at low birthweight and moderately high risk at high birthweight) and inversely associated with hypertension in adulthood with inconsistent evidence for cardiovascular disease. There is a lack of population-based studies examining the incidence of cardiometabolic outcomes in young adults born with low and high birthweights. To evaluate the association between birthweight and diabetes, hypertension, and ischemic heart disease (IHD) in young adulthood, we conducted a retrospective cohort study of 874,904 singletons born in Ontario, Canada, from 1994 to 2002, identified from population-based health administrative data. Separate Cox regression models examined birthweight in association with diabetes, hypertension, and IHD adjusting for confounders. Among adults 18-26 years, the diabetes incidence rate was 18.15 per 100,000 person-years, hypertension was 15.80 per 100,000 person-years, and IHD was 1.85 per 100,000 person-years. Adjusted hazard ratios (AHR) for the hazard of diabetes with low (<2500g) and high (>4000g), compared with normal (2500-4000g) birthweight, were 1.46 (95% CI 1.28, 1.68) and 1.09 (0.99, 1.21), respectively. AHR for hypertension with low and high birthweight were 1.34 (1.15, 1.56) and 0.86 (0.77, 0.97), respectively. AHR for IHD with low and high birthweight were 1.28 (0.80, 2.05) and 0.97 (0.71, 1.33), respectively. Overall, birthweight was associated with diabetes in young adults in a reverse J-shape and inversely with hypertension. There was insufficient evidence of an association with IHD. Further evidence is needed to understand the causal mechanisms between birthweight and cardiometabolic diseases in young adults.

Validation of Parent-reported Gestational Age Categories for Children Less Than 6 Years of Age

BACKGROUND

Preterm birth is an important outcome or exposure in epidemiologic research. When administrative data on measured gestational age is not available, parent-reported gestational age can be obtained from questionnaires, which is subject to potential bias. To our knowledge, few studies have assessed the validity of parent-reported gestational age categories, including commonly defined categories of preterm birth.

METHODS

We used linked data from primarily healthy children <6 years of age in TARGet Kids! in Toronto, Canada, and ICES administrative healthcare data from April 2011 to March 2020. We assessed the criterion validity of questionnaire-based parent-reported gestational age by calculating sensitivity and specificity for term (≥37 weeks), late preterm (34-36 weeks), and moderately preterm (32-33 weeks) gestational age categories, using administrative healthcare records of gestational age as the criterion standard. We conducted subgroup analyses for various parent and socioeconomic factors that may influence recall.

RESULTS

Of the 4684 participants, 97.3% correctly classified the gestational age category according to administrative healthcare data. Parent-reported gestational age sensitivity ranged from 83.7% to 98.5% and specificity ranged from 88.3% to 99.8%, depending on category. For each subgroup characteristic, sensitivity and specificity were all ≥70%. Lower educational attainment, lower family income, father reporting, ≥1 year since birth, ≥2 children, lower parent age, and reported gestational diabetes and/or hypertension were associated with slightly lower sensitivity and/or specificity.

CONCLUSIONS

In this linked cohort, parent-reported gestational age categories had high accuracy. Criterion validity varied minimally among some parent and socioeconomic factors. Our findings can inform future quantitative bias analyses.

Screening accuracy of the parent-report preschool Strengths and Difficulties Questionnaire in primary care

OBJECTIVE

To evaluate the screening test accuracy and reliability of the parent-report preschool Strengths and Difficulties Questionnaire (P-SDQ) in primary care settings.

METHODS

Children 24-48 months were recruited at scheduled primary care visits in Toronto, Canada. Parents completed the P-SDQ at baseline, 2 and 12 weeks. At 12 weeks, parents were invited to a semi-structured diagnostic phone interview, the Preschool Age Psychiatric Assessment (PAPA). Criterion validity between baseline P-SDQ scores (Total Difficulties Score [TDS], internalizing and externalizing subscale) and DSM-5 diagnoses on PAPA was evaluated using area under the curve (AUC) and calculating screening test properties (sensitivity and specificity). Test-retest reliability at baseline and 2 weeks was evaluated using intraclass correlation coefficient (ICC).

RESULTS

183 children were enrolled, mean age 39.3 (SD 7.4) months, 46.4% male, 120 (66%) completed P-SDQ at 2 weeks, 107 (58%) completed PAPA at 12 weeks. Of those with a PAPA, 26 (24%) had any psychiatric diagnosis, 22 (21%) had internalizing disorders, and 9 (8%) had externalizing disorders. TDS identified any diagnosis with AUC = 0.67 (95% CI: 0.55, 0.79); internalizing subscale identified internalizing disorders with AUC = 0.61 (95% CI: 0.47, 0.74); externalizing subscale identified externalizing disorders with AUC = 0.77 (95% CI: 0.60, 0.94). Sensitivity and specificity, and test-retest reliability, were satisfactory for TDS and externalizing subscale, and less satisfactory for the internalizing subscale.

CONCLUSION

The externalizing subscale has sufficient accuracy and reliability to identify children aged two to four years at risk for attention deficit/hyperactivity disorder and disruptive behavior disorders in primary care.

Timing of introduction to solid food, eczema and wheezing in later childhood: a longitudinal cohort study

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 < .001) among children without a family history of asthma who were breastfeeding when solid foods were introduced. There was little evidence of an association among the remaining strata for either outcome.

CONCLUSION

The findings of this study support recommendations to introduce solid food around 6 months of age.

New approaches and technical considerations in detecting outlier measurements and trajectories in longitudinal children growth data

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.

Late preterm birth and growth trajectories during childhood: a linked retrospective cohort study

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.

Evaluation of ethnic differences in cardiometabolic risk in children

PURPOSE

In adults, cardiometabolic conditions manifest differently by ethnicity with South Asians particularly predisposed. Whether these differences arise in childhood remains narrowly explored. To address this evidence gap, we examined whether children of different ethnicities display differences in cardiometabolic risk (CMR).

METHODS

A cross-sectional analysis was conducted among 5557 children (3-11 years). Multivariable linear regression models adjusted for age, sex, z-body mass index, and demographic factors were used to estimate differences in CMR outcomes between children with parents that self-reported European ancestry (reference group) and one of 13 other ethnicities (African, Arab, East Asian, Latin American, South Asian, Southeast Asian, Mixed Ethnicities, and Other). The primary outcome was a CMR score, calculated as the sum of age- and sex-standardized waist circumference, systolic blood pressure (SBP), glucose, log-triglycerides, and inverse high-density lipoprotein cholesterol (HDL-C), divided by √5.

RESULTS

Lower mean CMR scores were observed among children with African (β = -0.62, 95% CI: -0.92; -0.32) and East Asian (β = -0.41, 95% CI: -0.68, -0.15) ancestry compared to children with European ancestry. Children with South Asian ancestry had higher SBP (β = 2.25, 95% CI: 1.27, 3.22) and non-HDL-C (β = 0.17, 95% CI: 0.07, 0.26) than children with European ancestry.

CONCLUSIONS

Ethnic differences in CMR were observed in early and middle childhood.

A novel systematic pipeline for increased predictability and explainability of growth patterns in children using trajectory features

OBJECTIVE

Longitudinal patterns of growth in early childhood are associated with health conditions throughout life. Knowledge of such patterns and the ability to predict them can lead to better prevention and improved health promotion in adulthood. However, growth analyses are characterized by significant variability, and pattern detection is affected by the method applied. Moreover, pattern labelling is typically performed based on ad hoc methods, such as visualizations or clinical experience. Here, we propose a novel pipeline using features extracted from growth trajectories using mathematical, statistical and machine-learning approaches to predict growth patterns and label them in a systematic and unequivocal manner.

METHODS

We extracted mathematical and clinical features from 9577 children growth trajectories embedded with machine-learning predictions of the growth patterns. We experimented with two sets of features (CAnonical Time-series Characteristics and trajectory features specific to growth), developmental periods and six machine-learning classifiers. Clinical experts provided labels for the detected patterns and decision rules were created to associate the features with the labelled patterns. The predictive capacity of the extracted features was validated on two heterogenous populations (The Applied Research Group for Kids and the 2004 Pelotas Birth Cohort, based in Canada and Brazil, respectively).

RESULTS

Features predictive ability measured by accuracy and F1 score was ≥ 80% and ≥ 0.76 respectively in both cohorts. A small number of features (n = 74) was sufficient to distinguish between growth patterns in both cohorts. Slope, intercept of the trajectory, age at peak value, start value and change of the growth measure were among the top identified features.

CONCLUSION

Growth features can be reliably used as predictors of growth patterns and provide an unbiased understanding of growth patterns. They can be used as tool to reduce the effort to repeat analysis and variability concerning anthropometric measures, time points and analytical methods, in the context of the same or similar populations.

Examining the Double Burden of Underweight, Overweight/Obesity and Iron Deficiency among Young Children in a Canadian Primary Care Setting

There is little evidence on the prevalence of the double burden and association between body mass index (BMI) and iron deficiency among young children living in high-income countries. We conducted a cross-sectional study of healthy children, 12-29 months of age, recruited during health supervision visits in Toronto, Canada, and concurrently measured BMI and serum ferritin. The prevalence of a double burden of underweight (zBMI < -2) and iron deficiency or overweight/obesity (zBMI > 2) and iron deficiency was calculated. Regression models examined BMI and serum ferritin as continuous and categorical variables, adjusted for covariates. We found the following in terms of prevalence among 1953 children (mean age 18.3 months): underweight 2.6%, overweight/obesity 4.9%, iron deficiency 13.8%, iron-deficiency anemia 5.4%, underweight and iron deficiency 0.4%, overweight/obesity and iron deficiency 1.0%. The change in median serum ferritin for each unit of zBMI was -1.31 µg/L (95% CI -1.93, -0.68, p < 0.001). Compared with normal weight, we found no association between underweight and iron deficiency; meanwhile, overweight/obesity was associated with a higher odds of iron deficiency (OR 2.15, 95% CI 1.22, 3.78, p = 0.008). A double burden of overweight/obesity and iron deficiency occurs in about 1.0% of young children in this high-income setting. For risk stratification and targeted screening in young children, overweight/obesity should be added to the list of important risk factors.

Maternal Preconception Body Mass Index and Early Childhood Nutritional Risk

BACKGROUND

Risk factors for problematic child eating behaviors and food preferences are thought to begin during the preconception period. It is unknown if maternal preconception body mass index (BMI) is associated with child nutritional risk factors (eg, poor dietary intake and eating behaviors).

OBJECTIVES

We aimed to determine whether maternal preconception BMI was associated with child nutritional risk.

METHODS

In this longitudinal cohort study, a secondary data analysis of children ages 18 mo to 5 y were recruited from The Applied Research Group for Kids (TARGet Kids!), a primary care practice-based research network in Canada. The primary exposure was maternal preconception BMI. The primary outcome was parent-reported child nutritional risk score, measured using the Nutrition Screening for Every Preschooler/Toddler (NutriSTEP), an age-appropriate validated questionnaire. Fitted linear mixed effects models analyzed associations between maternal preconception BMI and child nutritional risk after adjusting for covariates.

RESULTS

This study included 4733 children with 8611 repeated NutriSTEP observations obtained between ages 18 mo to 5 y. The mean (standard deviation [SD]) maternal preconception BMI was 23.6 (4.4), where 73.1% of mothers had a BMI ≤24.9 kg/m2, and 26.9% had a BMI ≥25 kg/m2. The mean (SD) NutriSTEP total score was 13.5 (6.2), with 86.6% at low risk (score <21) and 13.4% at high risk (score ≥21). Each 1 unit increase in maternal preconception BMI was associated with a 0.09 increase in NutriSTEP total score (95% confidence interval [CI]: 0.05, 0.12; P ≤ 0.001). After stratification, each 1 unit increase in maternal BMI was associated with a 0.06 increase in mean NutriSTEP total score (95% CI: 0.007, 0.11; P = 0.025) in toddlers and 0.11 increase in mean NutriSTEP total score (95% CI: 0.07, 0.15; P < 0.001) in preschoolers.

CONCLUSION

Higher maternal preconception BMI is associated with slightly higher NutriSTEP total scores. This provides evidence that the preconception period may be an important time to focus on for improving childhood nutrition. This study was registered at clinicaltrials.gov as NCT01869530.

Validation of a parent proxy-reported beverage screener compared to a 24-hour dietary recall for the measurement of sugar-containing beverage intake among young children

Measures that can provide reasonably accurate estimates of sugar-containing beverage (SCB) intake among children are needed. The primary objective of this study was to evaluate the relative validity of a short beverage screener (Nutrition and Health Questionnaire, NHQ) compared to a 24-hour recall (Automated Self-Administered 24-h (ASA24) Dietary Assessment Tool-Canada) for assessing parent proxy-reported daily SCB intake among children aged 4-14 years from the TARGet Kids! research network in Toronto, Canada. Children for whom a NHQ completed between March 2018 and June 2019 and an ASA24 completed within one year were included. A total of 471 parents who completed the NHQ beverage screener were also asked to complete the ASA24. One-hundred sixty-three completed the ASA24 and of this group, 109 were analyzed. Estimates of daily intake of 100% juices, sweetened drinks and soda, and total SCBs from the two measures were compared. The mean difference in beverage intake, Spearman correlations, and Bland-Altman plots were estimated for continuous measures. The kappa coefficient, sensitivity, and specificity were calculated for dichotomous measures of any daily intake versus none. The mean difference in total SCB intake between the NHQ and ASA24 was 0.14 cups/day (95% CI 0.01, 0.29) and the correlation was 0.43 (95% CI 0.26, 0.57). Sensitivity and specificity for any daily SCB intake were 0.63 and 0.76, respectively. Overall, parent proxy-reporting of children's total SCB intake from a beverage screener can provide reasonable estimates of SCB intake when detailed dietary assessment is not feasible.

Effect of plant milk consumption on childhood growth: protocol for a systematic review

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.

Priority topics for child and family health research in community-based paediatric health care according to caregivers and health care professionals

Background

Patient-oriented research (POR) aligns research with stakeholders' priorities to improve health services and outcomes. Community-based health care settings offer an opportunity to engage stakeholders to determine the most important research topics to them. Our objectives were to identify unanswered questions that stakeholders had regarding any aspect of child and family health and prioritize their 'top 10' questions.

Methods

We followed the James Lind Alliance (JLA) priority setting methodology in partnership with stakeholders from the Northeast Community Health Centre (NECHC; Edmonton, Canada). We partnered with stakeholders (five caregivers, five health care professionals [HCPs]) to create a steering committee. Stakeholders were surveyed in two rounds (n = 125 per survey) to gather and rank-order unanswered questions regarding child and family health. A final priority setting workshop was held to finalize the 'top 10' list.

Results

Our initial survey generated 1,265 submissions from 100 caregivers and 25 HCPs. Out of scope submissions were removed and similar questions were combined to create a master list of questions (n = 389). Only unanswered questions advanced (n = 108) and were rank-ordered through a second survey by 100 caregivers and 25 HCPs. Stakeholders (n = 12) gathered for the final workshop to discuss and finalize the 'top 10' list. Priority questions included a range of topics, including mental health, screen time, COVID-19, and behaviour.

Conclusion

Our stakeholders prioritized diverse questions within our 'top 10' list; questions regarding mental health were the most common. Future patient-oriented research at this site will be guided by priorities that were most important to caregivers and HCPs.

Statistical haemoglobin thresholds to define anaemia across the lifecycle

Detection of anaemia is critical for clinical medicine and public health. Current WHO values that define anaemia are statistical thresholds (5 ^th centile) set over 50 years ago, and are presently <110g/L in children 6-59 months, <115g/L in children 5-11 years, <110g/L in pregnant women, <120g/L in children 12-14 years of age, <120g/L in non-pregnant women, and <130g/L in men. Haemoglobin is sensitive to iron and other nutrient deficiencies, medical illness and inflammation, and is impacted by genetic conditions; thus, careful exclusion of these conditions is crucial to obtain a healthy reference population. We identified data sources from which sufficient clinical and laboratory information was available to determine an apparently healthy reference sample. Individuals were excluded if they had any clinical or biochemical evidence of a condition that may diminish haemoglobin concentration. Discrete 5 ^th centiles were estimated along with two-sided 90% confidence intervals and estimates combined using a fixed-effect approach. Estimates for the 5 ^th centile of the healthy reference population in children were similar between sexes. Thresholds in children 6-23 months were 104.4g/L [90% CI 103.5, 105.3]; in children 24-59 months were 110.2g/L [109.5, 110.9]; and in children 5-11 years were 114.1g/L [113.2, 115.0]. Thresholds diverged by sex in adolescents and adults. In females and males 12-17 years, thresholds were 122.2g/L [121.3, 123.1] and 128.2 [126.4, 130.0], respectively. In adults 18-65 years, thresholds were 119.7g/L [119.1, 120.3] in non-pregnant females and 134.9g/L [134.2, 135.6] in males. Limited analyses indicated 5 ^th centiles in first-trimester pregnancy of 110.3g/L [109.5, 111.0] and 105.9g/L [104.0, 107.7] in the second trimester. All thresholds were robust to variations in definitions and analysis models. Using multiple datasets comprising Asian, African, and European ancestries, we did not identify novel high prevalence genetic variants that influence haemoglobin concentration, other than variants in genes known to cause important clinical disease, suggesting non-clinical genetic factors do not influence the 5 ^th centile between ancestries. Our results directly inform WHO guideline development and provide a platform for global harmonisation of laboratory, clinical and public health haemoglobin thresholds.

Parent and physician beliefs, perceptions and knowledge of plant milks for children

Background: Parent and physician perceptions of plant milk are unclear. Aim: To explore parent and physician perceptions of plant milk for children and to gain a better understanding of why parents and physicians might choose plant milk for children. Methods: A mixed methods study was conducted using a questionnaire and interviews with parents and physicians participating in the TARGet Kids! cohort study. Questionnaire data were analyzed using descriptive statistics. Interview transcripts were analyzed using thematic analysis. Results: Parents reported a variety of reasons for choosing plant milk for their children including concerns around allergies, the environment, animal welfare, plant-based diet, health benefits, taste and hormones in cow's milk. Parents gave their children various types of plant milks and physicians provided various recommendations to parents of children not consuming cow's milk. Our study identified that 79% of parents and 51% of physicians were unaware that soy milk is the recommended cow's milk substitute for children. Additionally, 26% of parents did not know some plant milks are not fortified and can contain added sugar. Three main themes were identified from interviews about why parents and physicians may choose plant milk for children: (i) healthiness of plant milk; (ii) concerns about hormones; and (iii) environmental impacts. Conclusions: Parents and physicians choose the milk that they believe is healthiest for their child or patient. However, a lack of clarity on the effects of plant milk consumption on children's health resulted in conflicting views on whether plant milk or cow's milk is healthier for children.

Breastfeeding support provided by lactation consultants in high-income countries for improved breastfeeding rates, self-efficacy, and infant growth: a systematic review and meta-analysis protocol

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).

Centre-based childcare in early childhood and growth in later childhood: a prospective cohort study

BACKGROUND

Attending government-regulated centre-based childcare may influence important health behaviours including dietary quality, physical activity and routines related to child growth. However, the relationship between centre-based childcare and childhood obesity remains unclear.

OBJECTIVES

The primary objective was to evaluate the association between centre-based childcare attendance in early childhood and body mass index z-score (zBMI) in later childhood. Secondary objectives included exploring whether family income, child sex, or non-centre-based setting modified these relationships.

METHODS

A prospective cohort study of children aged 1 to 10 years who participated in the TARGet Kids! cohort was conducted. Linear mixed-effect modelling was used to evaluate the relationship between centre-based childcare attendance (in hours/week) compared to non-centre-based childcare between 1-4 years of age and zBMI between 4 and 10 years of age. Generalised estimating equation modelling was used to explore weight status categories. Models were adjusted for confounders and effect modification was explored.

RESULTS

A total of 3503 children were included. Children who attended centre-based childcare full-time (40 h/week) had 0.11 (95% CI: -0.19, -0.03; p = 0.01) lower zBMI at 4 and 7 years of age and lower odds of overweight and obesity at 4 years (OR 0.78; 95% CI: 0.62, 0.97; p = 0.03), but no evidence of an association was found at 10 years of age. Children from families with income < $50,000CDN who attended centre-based childcare full-time had 0.32 (95% CI: -0.50, -0.14; p = 0.001) lower zBMI and lower odds of overweight and obesity (OR 0.52; 95% CI: 0.28, 0.99; p = 0.05) at 10 years of age.

CONCLUSIONS

Attending centre-based childcare in early childhood was associated with a lower zBMI and odds of overweight and obesity in later childhood. These associations were stronger for children from lower income families. Centre-based childcare may be an early intervention for the prevention of childhood obesity.

CLINICAL TRIAL

Clinical Trial Registry Number: NCT01869530 (clinicaltrials.gov).

Maternal BMI in the preconception period, and association with child zBMI growth rates

BACKGROUND

Elevated body mass index (BMI) and rapid growth in early childhood are important predictors of obesity risk. The association between maternal preconception BMI and child growth rates is unclear.

OBJECTIVES

To assess the association between measured maternal preconception BMI and child age- and sex- standardized WHO BMI z-score (zBMI) growth rates and mean zBMI, in children aged 0-10 years old.

METHODS

A longitudinal cohort study was conducted with children (n = 499) enrolled in The Applied Research Group for Kids (TARGet Kids!) primary care practice-based research cohort. Maternal BMI was measured during the preconception period, defined as the 2 years prior to pregnancy. Repeated measures of child weight and height were obtained between 0 and 10 years of age. Linear mixed models were used to evaluate the association between maternal BMI and child zBMI growth rates and mean zBMI.

RESULTS

Maternal preconception BMI was associated with child zBMI growth rate during some growth periods, with the strongest association from age 0 to 4 months; a 5 kg/m2 higher maternal BMI was associated with 0.031 zBMI SD unit/mo higher growth rate (p = 0.004), and 0.186 SD unit higher mean child zBMI (p = 0.0002).

CONCLUSIONS

Maternal preconception BMI was associated with growth rate and mean zBMI in early childhood. The preconception period may be an important target for health interventions to promote healthy child growth rate and weight outcomes.

Changes in Pediatric Movement Behaviors During the COVID-19 Pandemic by Stages of Lockdown in Ontario, Canada: A Longitudinal Cohort Study

BACKGROUND

Children's movement behaviors have been affected by the COVID-19 pandemic; however, little is known regarding movement behavior patterns over time by government-issued lockdowns. Our primary objective was to evaluate how children's movement behaviors changed by stages of lockdown/reopening in Ontario, Canada, from 2020 to 2021.

METHODS

A longitudinal cohort study with repeated measures of exposure and outcomes was conducted. The exposure variables were dates from before and during COVID-19 when child movement behavior questionnaires were completed. Lockdown/reopening dates were included as knot locations in the spline model. The outcomes were daily screen, physical activity, outdoor, and sleep time.

RESULTS

A total of 589 children with 4805 observations were included (53.1% boys, 5.9 [2.6] y). On average, screen time increased during the first and second lockdowns and decreased during the second reopening. Physical activity and outdoor time increased during the first lockdown, decreased during the first reopening, and increased during the second reopening. Younger children (<5 y) had greater increases in screen time and lower increases in physical activity and outdoor time than older children (≥5 y).

CONCLUSIONS

Policy makers should consider the impact of lockdowns on child movement behaviors, especially in younger children.

Predictive Validity of the Infant Toddler Checklist in Primary Care at the 18-month Visit and School Readiness at 4 to 6 Years

OBJECTIVE

The American Academy of Pediatrics recommends developmental surveillance and screening in early childhood in primary care. The 18-month visit may be an ideal time for identification of children with delays in language and communication, or symptoms of autism spectrum disorder (ASD). Little is known about the predictive validity of developmental screening tools administered at 18 months. Our objective was to examine the predictive validity of the Infant Toddler Checklist (ITC) at the 18-month health supervision visit, using school readiness at kindergarten age as the criterion measure.

METHODS

We designed a prospective cohort study, recruiting in primary care in Toronto, Canada. Parents completed the ITC at the 18-month visit. Teachers completed the Early Development Instrument (EDI) when the children were in Kindergarten, age 4-6 years. We calculated screening test properties with 95% confidence intervals (CIs). We used multivariable logistic and linear regression analyses adjusted for important covariates.

RESULTS

Of 293 children (mean age 18 months), 30 (10.2%) had a positive ITC including: concern for speech delay (n = 11, 3.8%), concern for other communication delay (n = 13, 4.4%), and concern for both (n = 6, 2.0%). At follow-up (mean age 5 years), 54 (18.4%) had overall EDI vulnerability, 19 (6.5%) had vulnerability on the 2 EDI communication domains. The ITC sensitivity ranged from 11% to 32%, specificity from 91% to 96%, false positive rates from 4% to 9%, PPV from 16% to 35%, NPV from 83% to 95%. A positive ITC screen and ITC concern for speech delay were associated with lower scores in EDI communication skills and general knowledge (β = -1.08; 95% CI: -2.10, -0.17; β = -2.35; 95% CI: -3.63, -1.32) and EDI language and cognitive development (β = -0.62; 95% CI: -1.25, -0.18; β = -1.22; 95% CI: -2.11, -0.58).

CONCLUSIONS

The ITC demonstrated high specificity suggesting that most children with a negative ITC screen will demonstrate school readiness at 4-6 years, and low false positive rates, minimizing over-diagnosis. The ITC had low sensitivity highlighting the importance of ongoing developmental surveillance and screening.

Patterns of parent screen use, child screen time, and child socio-emotional problems at 5 years

Digital media screens have become an essential part of our family life. However, we have insufficient knowledge about parental screen use patterns and how these affect children's socio-emotional development. In total, 867 Canadian parents of 5-year-old children from the TARGet Kids! Cohort (73.1% mothers, mean ± SD age = 38.88 ± 4.45 years) participated in this study from 2014 to the end of 2019. Parents reported parental and child time on television (TV) and handheld devices and completed the Strengths and Difficulties Questionnaire (SDQ). Latent profile analysis identified six latent profiles of parent screen use: low handheld users (P1, reference; n = 323), more TV than handheld (P2; n = 261), equal TV and handheld (P3; n = 177), more handheld than TV (P4; n = 57), high TV and handheld (P5; n = 38), and extremely high TV and handheld (P6; n = 11). Parents that were more likely to belong to P6 were also more likely to be living in single-parent households compared to P1 (estimate = -1.49 ± 0.70), p = .03). High membership probability for P2 (estimate = -0.67 ± 0.32, p = .04) and P4 (estimate = -1.42 ± 0.40, p < 0.001) was associated with lower household income compared to P1. Children of parents with higher P4 (χ²  = 12.32, p < 0.001) or P5 (χ²  = 9.54, p = .002) membership probability had higher total screen time compared to P1. Finally, a higher likelihood to belong to P6 (χ²  = 6.82, p = .009) was associated with a higher SDQ Total Difficulties Score compared to P1. Thus, patterns of parent screen use were associated with child screen use and child socio-emotional problems. The emerging link between parental screen use profiles and child behaviors suggests the need for more research on parent screen time.

Parents' perspectives on SARS-CoV-2 vaccinations for children: a qualitative analysis

BACKGROUND

Uptake of the SARS-CoV-2 vaccine for children aged 5-11 years has been lower than anticipated in Canada. Although research has explored parental intentions toward SARS-CoV-2 vaccination for children, parental decisions regarding vaccinations have not been studied in-depth. We sought to explore reasons why parents chose to vaccinate or not vaccinate their children against SARS-CoV-2 to better understand their decisions.

METHODS

We conducted a qualitative study involving in-depth individual interviews with a purposive sample of parents in the Greater Toronto Area, Ontario, Canada. We conducted interviews via telephone or video call from February to April 2022 and analyzed the data using reflexive thematic analysis.

RESULTS

We interviewed 20 parents. We found that parental attitudes toward SARS-CoV-2 vaccinations for their children represented a complex continuum of concern. We identified 4 cross-cutting themes: the newness of SARS-CoV-2 vaccines and the evidence supporting their use; the perceived politicization of guidance for SARS-CoV-2 vaccination; the social pressure surrounding SARS-CoV-2 vaccinations; and the weighing of individual versus collective benefits of vaccination. Parents found making a decision about vaccinating their child challenging and expressed difficulty sourcing and evaluating evidence, determining the trustworthiness of guidance, and balancing their own conceptions of health care decisions with societal expectations and political messaging.

INTERPRETATION

Parents' experiences making decisions regarding SARS-CoV-2 vaccination for their children were complex, even for those who were supportive of SARS-CoV-2 vaccinations. These findings provide some explanation for the current patterns of uptake of SARS-CoV-2 vaccination among children in Canada; health care providers and public health authorities can consider these insights when planning future vaccine rollouts.

Factors associated with research participation in a large primary care practice-based pediatric cohort: Results from the TARGet Kids! longitudinal cohort study

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.

Chronic Iron Deficiency and Cognitive Function in Early Childhood

BACKGROUND AND OBJECTIVES

A landmark longitudinal study, conducted in Costa Rica in the 1980s, found that children with chronic iron deficiency compared with good iron status in infancy had 8 to 9 points lower cognitive scores, up to 19 years of age. Our objective was to examine this association in a contemporary, high-resource setting.

METHODS

This was a prospective observational study of children aged 12 to 40 months screened with hemoglobin and serum ferritin. All parents received diet advice; children received oral iron according to iron status. After 4 months, children were grouped as: chronic iron deficiency (iron deficiency anemia at baseline or persistent nonanemic iron deficiency) or iron sufficiency (IS) (IS at baseline or resolved nonanemic iron deficiency). Outcomes measured at 4 and 12 months included the Early Learning Composite (from the Mullen Scales of Early Learning) and serum ferritin.

RESULTS

Of 1478 children screened, 116 were included (41 chronic, 75 sufficient). Using multivariable analyses, the mean between-group differences in the Early Learning Composite at 4 months was -6.4 points (95% confidence interval [CI]: -12.4 to -0.3, P = .04) and at 12 months was -7.4 points (95% CI: -14.0 to -0.8, P = .03). The mean between-group differences in serum ferritin at 4 months was 14.3 μg/L (95% CI: 1.3-27.4, P = .03) and was not significantly different at 12 months.

CONCLUSIONS

Children with chronic iron deficiency, compared with children with IS, demonstrated improved iron status, but cognitive scores 6 to 7 points lower 4 and 12 months after intervention. Future research may examine outcomes of a screening strategy on the basis of early detection of iron deficiency using serum ferritin.

Quantifying the extent of visit irregularity in longitudinal data

The timings of visits in observational longitudinal data may depend on the study outcome, and this can result in bias if ignored. Assessing the extent of visit irregularity is important because it can help determine whether visits can be treated as repeated measures or as irregular data. We propose plotting the mean proportions of individuals with 0 visits per bin against the mean proportions of individuals with >1 visit per bin as bin width is varied and using the area under the curve (AUC) to assess the extent of irregularity. The AUC is a single score which can be used to quantify the extent of irregularity and assess how closely visits resemble repeated measures. Simulation results confirm that the AUC increases with increasing irregularity while being invariant to sample size and the number of scheduled measurement occasions. A demonstration of the AUC was performed on the TARGet Kids! study which enrolls healthy children aged 0-5 years with the aim of investigating the relationship between early life exposures and later health problems. The quality of statistical analyses can be improved by using the AUC as a guide to select the appropriate analytic outcome approach and minimize the potential for biased results.

Managing Obesity in Young Children: A Multiple Methods Study Assessing Feasibility, Acceptability, and Implementation of a Multicomponent, Family-Based Intervention

Background: We developed a multicomponent, family-based intervention for young children with obesity consisting of parent group sessions, home nursing visits, and multidisciplinary clinical encounters. Our objective was to assess intervention feasibility, acceptability, and implementation. Methods: From 2017 to 2020, we conducted a multiple methods study in the obesity management clinic at a tertiary children's hospital (Toronto, Canada). We included 1-6 year olds with a body mass index ≥97th percentile and their parents; we also included health care providers (HCPs) who delivered the intervention. To assess feasibility, we performed a pilot randomized controlled trial (RCT) comparing the intervention to usual care. To explore acceptability, we conducted parent focus groups. To explore implementation, we examined contextual factors with HCPs using the Consolidated Framework for Implementation Research. Results: There was a high level of ineligibility (n = 34/61) for the pilot RCT. Over 21 months, 11 parent-child dyads were recruited; of 6 randomized to the intervention, 3 did not participate in group sessions or home visits. In focus groups, themes identified by parents (n = 8) related to information provided at referral; fit between the intervention and patient needs; parental gains from participating in the intervention; and feasibility of group sessions. HCPs (n = 10) identified contextual factors that were positively and negatively associated with intervention implementation. Conclusions: We encountered challenges related to intervention feasibility, acceptability, and implementation. Lessons learned from this study will inform the next iteration of our intervention and are relevant to intervention development and implementation for young children with obesity. Clinical Trial Registration number: NCT03219658.

Sleep Duration and Internalizing Symptoms in Children

OBJECTIVE

Emotional problems such as anxiety and low mood have been associated with sleep problems in children. The study's objectives were to 1) assess the association between sleep duration and internalizing symptoms (anxiety and low mood) in children aged 5-12 years (y), and 2) evaluate whether insufficient sleep according to the National Sleep Foundation (NSF) guidelines is associated with internalizing symptoms.

METHODS

A cross-sectional study of N =796 children aged 5-12y, recruited from primary care physicians' offices in Toronto, Canada was conducted through the TARGet Kids! research network. Using linear regression, we investigated 1) the cross-sectional association between parent reported 24-hour sleep duration (hours) and parent reported symptoms using the Strengths and Difficulties Questionnaire (SDQ), controlling for child age, sex, family income, maternal education, family composition, and standardized body-mass index (zBMI). The analysis was repeated using insufficient sleep per NSF guideline as the independent variable.

RESULTS

Sleep duration was inversely associated with internalizing symptoms, B estimate = -0.33 (95%CI -0.57, -0.07), p=0.012. Twenty-eight (14%) children aged 5 y, and 36 (6%) of those aged 6-12y, experienced insufficient sleep. There was a trend toward association between insufficient sleep and internalizing symptoms, B estimate = 0.64 (-0.09, 1.38), p=0.086.

CONCLUSION

The relationship between insufficient sleep and internalizing symptoms among children requires further elucidation. Children who show internalizing symptoms may benefit from interventions supporting sleep.

Body Weight at Age Four Years and Readiness to Start School: A Prospective Cohort Study

Background: Adolescents with obesity have lower academic performance, but little is known about the association between body weight in early childhood and school readiness. The objective was to examine the association between age- and sex-standardized body mass index (zBMI) and body weight status and school readiness in young children. Methods: A prospective cohort study in Toronto, Canada, was conducted in young children enrolled in TARGet Kids!. Children's weight and height were measured before the start of kindergarten. Children's school readiness was measured by the Early Development Instrument (EDI), a validated teacher-completed instrument that assesses children's skills and behaviors in five developmental domains in kindergarten. Generalized estimating equations, adjusted for relevant confounders, were used in the analysis. Results: The study included 1015 children (1217 observations): 52% were male and mean age at zBMI was 4.2 years [50 months (SD 12.1)] and school readiness was 5.2 years [62.7 months (SD 6.9)]. There was no evidence found that zBMI was associated with school readiness. However, in a post hoc analysis, being classified as overweight or with obesity in kindergarten was associated with twofold higher odds of vulnerability in school readiness and a lower social competence score compared with their normal weight peers. Conclusions: Being classified as overweight or with obesity was associated with poor school readiness in year 2 of kindergarten. Early interventions to promote healthy growth before school entry may help promote development and school readiness in young children. www.clinicaltrials.gov (NCT01869530).

Underweight in the First 2 Years of Life and Growth in Later Childhood

IMPORTANCE

Few studies have examined the association between underweight in the first 2 years and growth in later childhood in high-income countries.

OBJECTIVE

To evaluate the associations of underweight in the first 2 years of life with body mass index (calculated as weight in kilograms divided by height in meters squared) z score (zBMI), weight-for-age z score (WAZ), and height-for-age z score (HAZ) from ages 2 to 10 years.

DESIGN, SETTING, AND PARTICIPANTS

This prospective cohort study was conducted between February 2008 to September 2020 in The Applied Research Group for Kids! practice-based research network in Toronto, Canada. Participants included healthy children aged 0 to 10 years. Data were analyzed from October 2020 to December 2021.

EXPOSURES

Underweight (ie, zBMI less than -2, per the World Health Organization) in the first 2 years of life.

MAIN OUTCOMES AND MEASURES

The primary outcome was zBMI from ages 2 to 10 years. Linear mixed-effects models were used to account for multiple growth measures over time.

RESULTS

A total of 5803 children were included in the primary analysis. At baseline, the mean (SD) age was 4.07 (5.62) months, 2982 (52.2%) were boys, and 550 children (9.5%) were underweight. Underweight in the first 2 years was associated with lower zBMI (difference, -0.39 [95% CI, -0.48 to -0.31]) at 10 years and lower HAZ (difference, -0.24 [95% CI, -0.34 to -0.14]) at age 2 years. Stratified by sex, at age 10 years, girls and boys with underweight in the first 2 years both had lower zBMI (girls: difference, -0.47 [95% CI, -0.59 to -0.34]; boys: difference, -0.32 [95% CI, -0.44 to -0.20]). At age 10 years, children with underweight and a lower zBMI growth rate in the first 2 years had lower zBMI (difference, -0.64 [95% CI, -0.77 to -0.53) and HAZ (difference, -0.12 [-0.24 to -0.01]), while children with underweight and a higher zBMI growth rate in the first 2 years had similar zBMI (difference, -0.11 [95% CI, -0.22 to 0.001]) and higher HAZ (difference, 0.16 [95% CI, 0.05 to 0.27]) compared with children who did not have underweight in the first 2 years.

CONCLUSIONS AND RELEVANCE

In this prospective cohort study, children with underweight in the first 2 years of life had lower zBMI and HAZ in later childhood. These associations were attenuated among children with a higher growth rate in the first 2 years.

Predictive validity of the Infant Toddler Checklist in primary care at the 18-month visit and developmental diagnosis at 3-5 years: a prospective cohort study

OBJECTIVE

There is international variation in recommendations regarding developmental screening and growing recognition of the low sensitivity of commonly used developmental screening tools. Our objective was to examine the predictive validity of the Infant Toddler Checklist (ITC) at 18 months to predict a developmental diagnosis at 3-5 years, in a primary care setting.

METHODS

We designed a prospective cohort study, recruiting in primary care in Toronto, Canada. Parents completed the ITC at the 18-month visit and reported developmental diagnosis at 3-5 years (developmental delay, autism spectrum disorder (ASD), attention deficit hyperactivity disorder (ADHD), learning problem). We calculated screening test properties with 95% CIs. We used multivariable logistic regression analyses adjusted for important covariates.

RESULTS

In the final sample (n=488), mean age at screening was 18.5 (SD 1.1) months, and at follow-up was 46.6 (SD 10.0) months. At screening, 46 (9.4%) had a positive ITC. At follow-up, 26 (5.3%) had a developmental diagnosis, including: developmental delay (n=22), ASD (n=4), ADHD (n=1), learning problem (n=1); parents of two children each reported two diagnoses (total of 28 diagnoses). Of four children with a diagnosis of ASD at follow-up, three had a positive ITC at 18 months. The ITC specificity (92%, 95% CI: 89% to 94%) and negative predictive value (96%, 95% CI: 95% to 97%) were high; false positive rate was low (8%, 95% CI: 6% to 11%); sensitivity was low (31%, 95% CI: 14% to 52%). There was a strong association between a positive ITC at 18 months and later developmental diagnosis (adjusted OR 4.48, 95% CI: 1.72 to 11.64; p=0.002).

CONCLUSION

The ITC had high specificity, high negative predictive value, low false positive rate, and identified children with later developmental delay and ASD. The ITC had low sensitivity, similar to other screening tools underscoring the importance of continuous developmental surveillance at all health supervision visits.

Vegetarian Diet, Growth, and Nutrition in Early Childhood: A Longitudinal Cohort Study

OBJECTIVES

The primary objective of this study was to examine the relationships between vegetarian diet and growth, micronutrient stores, and serum lipids among healthy children. Secondary objectives included exploring whether cow's milk consumption or age modified these relationships.

METHODS

A longitudinal cohort study of children aged 6 months to 8 years who participated in the TARGet Kids! cohort study. Linear mixed-effect modeling was used to evaluate the relationships between vegetarian diet and BMI z-score (zBMI), height-for-age z-score, serum ferritin, 25-hydroxyvitamin D, and serum lipids. Generalized estimating equation modeling was used to explore weight status categories. Possible effect modification by age and cow's milk consumption was examined.

RESULTS

A total of 8907 children, including 248 vegetarian at baseline, participated. Mean age at baseline was 2.2 years (SD 1.5). There was no evidence of an association between vegetarian diet and zBMI, height-for-age z-score, serum ferritin, 25-hydroxyvitamin D, or serum lipids. Children with vegetarian diet had higher odds of underweight (zBMI <-2) (odds ratio 1.87, 95% confidence interval 1.19 to 2.96; P = .007) but no association with overweight or obesity was found. Cow's milk consumption was associated with higher nonhigh-density lipoprotein cholesterol (P = .03), total cholesterol (P = .04), and low-density lipoprotein cholesterol (P = .02) among children with vegetarian diet. However, children with and without vegetarian diet who consumed the recommended 2 cups of cow's milk per day had similar serum lipids.

CONCLUSIONS

Evidence of clinically meaningful differences in growth or biochemical measures of nutrition for children with vegetarian diet was not found. However, vegetarian diet was associated with higher odds of underweight.

Association between gut MIcrobiota, GROWth and Diet in peripubertal children from the TARGet Kids! cohort (The MiGrowD) study: protocol for studying gut microbiota at a community-based primary healthcare setting

INTRODUCTION

The gut microbiota interacts with diet to affect body health throughout the life cycle. Critical periods of growth, such as infancy and puberty, are characterised by microbiota remodelling and changes in dietary habits. While the relationship between gut microbiota and growth in early life has been studied, our understanding of this relationship during puberty remains limited. Here, we describe the MIcrobiota, GROWth and Diet in peripubertal children (The MiGrowD) study, which aims to assess the tripartite growth-gut microbiota-diet relationship at puberty.

METHODS AND ANALYSIS

The MiGrowD study will be a cross-sectional, community-based study involving children 8-12 years participating in the TARGet Kids!

COHORT

TARGet Kids! is a primary healthcare practice-based research network in Canada. Children will be asked to provide a stool sample, complete two non-consecutive 24-hour dietary recalls and a pubertal self-assessment based on Tanner Stages. Anthropometry will also be conducted. The primary outcome is the association between gut microbiota composition and longitudinal growth from birth until entry into the study. Anthropometrics data from birth will be from the data collected prospectively through TARGet Kids!. Body mass index z-scores will be calculated according to WHO. The secondary outcome is the association between gut microbiota, diet and pubertal stage.

ETHICS AND DISSEMINATION

Ethics approval has been obtained by the Hospital for Sick Children and St. Michael's Hospital-Unity Health, and the University of Toronto. Results will be disseminated in the public and academic sector, including participants, TARGet Kids! primary healthcare physicians teams, scientists via participation in the TARGet Kids! science and physician meetings, conferences and publications in peer-reviewed journals. The MiGrowD study results will help researchers understand the relationships underlying growth, gut microbiota and pubertal maturation in children.

Association of Late Preterm Birth and Size for Gestational Age With Cardiometabolic Risk in Childhood

IMPORTANCE

The long-term cardiometabolic consequences of late preterm birth (34-36 weeks' gestation) are not well understood.

OBJECTIVE

To assess whether late preterm birth and size for gestational age are associated with cardiometabolic risk (CMR) in childhood.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study included 1742 children born in Ontario, Canada, between April 1, 2006, and September 30, 2014, and followed up until September 30, 2019. Data from children enrolled in The Applied Research Group for Kids (TARGet Kids!) primary care practice-based research network were linked to administrative health care data at ICES (formerly known as the Institute for Clinical Evaluative Sciences). Participants were excluded if they had conditions affecting growth (eg, failure to thrive or cystic fibrosis), any acute or chronic conditions (other than asthma and high-functioning autism), severe developmental delay, or families who were unable to communicate in English.

EXPOSURES

Late preterm birth, gestational age as a continuous measure, and size for gestational age.

MAIN OUTCOMES AND MEASURES

The primary outcome was composite CMR score (overall age- and sex-standardized z score of CMR components, including waist circumference, log triglyceride level, glucose level, systolic blood pressure, and high-density lipoprotein cholesterol level). Secondary outcomes were the individual CMR components. Multivariable linear regression analysis was used to separately evaluate the associations of late preterm birth, continuous gestational age, and size for gestational age with CMR at ages 3 to 12 years.

RESULTS

Among 2440 eligible children, 1742 (mean [SD] age, 5.6 [2.2] years; 951 boys [54.6%]) were included in the final cohort. Overall, 87 children (5.0%) were born moderately preterm (<34 weeks' gestation), 145 (8.3%) were born late preterm (34-36 weeks' gestation), 455 (26.1%) were born early term (37-38 weeks' gestation), and 1055 (60.6%) were born full term (≥39 weeks' gestation). Compared with children born full term, those born moderately preterm (adjusted β = 0.50; 95% CI, 0.24-0.75) and late preterm (adjusted β = 0.27; 95% CI, 0.06-0.47) had higher CMR scores. Each additional gestational week was associated with a 0.06 U (adjusted β; 95% CI, -0.08 to -0.03 U) decrease in CMR.

CONCLUSIONS AND RELEVANCE

In this study, children born late preterm and moderately preterm had higher CMR. These results suggest that screening and early-life interventions for these children may prevent cardiometabolic outcomes.

Parent Engagement in a COVID-19 Cohort Study of Children and Families: Successes, Challenges and Next Steps

This article describes the methods, successes and challenges of engaging parents while studying the impacts of COVID-19 on healthy children and families. Parent partners in a Parent and Clinician Team (PACT) informed study aims, supported feasibility and recommended changes to enhance participation. PACT members stated that they felt a sense of connectedness and purpose by contributing to COVID-19 research. Engagement increased by parents acquiring new roles, attending more frequent meetings and co-creating alternative methods of engagement. Recruiting new PACT members was challenging, likely due to limited time and resources available to parents of young children during a pandemic.

Children's screen use and school readiness at 4-6 years: prospective cohort study

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.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-12629-8.

Understanding income-related differences in distribution of child growth, behaviour and development using a cross-sectional sample of a clinical cohort study

OBJECTIVES

Children from low-income households are at an increased risk of social, behavioural and physical health problems. Prior studies have generally relied on dichotomous outcome measures. However, inequities may exist along the range of outcome distribution. Our objective was to examine differences in distribution of three child health outcomes by income categories (high vs low): body mass index (BMI), behaviour difficulties and development.

DESIGN AND SETTING

This was a cross-sectional study using data from a primary care-based research network with sites in three Canadian cities, and 15 practices enrolling participants.

PARTICIPANTS, INDEPENDENT VARIABLE AND OUTCOMES

The independent variable was annual household income, dichotomised at the median income for Toronto (<$C80 000 or ≥$C80 000). Outcomes were: (1) growth (BMI z-score (zBMI) at 5 years, 1628 participants); (2) behaviour (Strengths and Difficulties Questionnaire (SDQ) at 3-5 years, 649 participants); (3) development (Infant Toddler Checklist (ITC) at 18 months, 1405 participants). We used distributional decomposition to compare distributions of these outcomes for each income group, and then to construct a counterfactual distribution that describes the hypothetical distribution of the low-income group with the predictor profile of the higher-income group.

RESULTS

We included data from 1628 (zBMI), 649 (SDQ) and 1405 (ITC) children. Children with lower family income had a higher risk distribution for all outcomes. For all outcomes, thecounterfactual distribution, which represented the distribution of children with lower-income who were assigned the predictor profile of the higher-income group, was more favourable than their observed distributions.

CONCLUSION

Comparing the distributions of child health outcomes and understanding different risk profiles for children from higher-income and lower-income groups can offer a deeper understanding of inequities in child health outcomes. These methods may offer an approach that can be implemented in larger datasets to inform future interventions.

Association Between Physical Activity, Screen Time and Sleep, and School Readiness in Canadian Children Aged 4 to 6 Years

OBJECTIVE

School readiness is strongly associated with a child's future school success and well-being. The primary objective of this study was to determine whether meeting 24-hour movement guidelines (national physical activity, sedentary behaviors, and sleep recommendations) was associated with school readiness measured with mean scores in each of the 5 developmental domains of the Early Development Instrument (EDI) in Canadian children aged 4 to 6 years. Secondary objectives include examining the following: (1) the association between meeting 24-hour movement guidelines and overall vulnerability in school readiness and (2) the association between meeting individual physical activity, screen use and sleep recommendations, and overall school readiness.

METHODS

A prospective cohort study was performed using data from children (aged 4-6 years) who participated in a large-scale primary care practice-based research network.

RESULTS

Of the 739 participants (aged 5.9 + 0.12 years) in this prospective cohort study, 18.2% met the 24-Hour Movement Guidelines. Linear regression models (adjusted for child/family demographic characteristics, number of siblings, immigration status, and annual household income) revealed no evidence of an association between meeting all 24-hour movement guidelines and any of the 5 domains of the EDI (p > 0.05). Adjusted linear regression models revealed evidence of an association between meeting screen use guidelines and the "language and cognitive development" (β = 0.16, p = 0.004) domain, and for the sleep guideline, there was a statistically significant association with the "physical health and well-being" (β = 0.23, p = 0.001), the "language and cognitive development" (β = 0.10, p = 0.003), and the "communication skills and general knowledge" (β = 0.18, p < 0.001) domain.

CONCLUSION

Early lifestyle interventions targeting screen use and sleep may be beneficial for improving a child's readiness for school.

Delay in childhood vaccinations during the COVID-19 pandemic

OBJECTIVES

In many jurisdictions, routine medical care was reduced in response to the COVID-19 pandemic. The objective of this study was to determine whether the frequency of on-time routine childhood vaccinations among children age 0-2 years was lower following the COVID-19 declaration of emergency in Ontario, Canada, on March 17, 2020, compared to prior to the pandemic.

METHODS

We conducted a longitudinal cohort study of healthy children aged 0-2 years participating in the TARGet Kids! primary care research network in Toronto, Canada. A logistic mixed effects regression model was used to determine odds ratios (ORs) for delayed vaccination (> 30 days vs. ≤ 30 days from the recommended date) before and after the COVID-19 declaration of emergency, adjusted for confounding variables. A Cox proportional hazards model was used to explore the relationship between the declaration of emergency and time to vaccination.

RESULTS

Among 1277 children, the proportion of on-time vaccinations was 81.8% prior to the COVID-19 declaration of emergency and 62.1% after (p < 0.001). The odds of delayed vaccination increased (odds ratio = 3.77, 95% CI: 2.86-4.96), and the hazard of administration of recommended vaccinations decreased after the declaration of emergency (hazard ratio = 0.75, 95% CI: 0.60-0.92). The median vaccination delay time was 5 days (95% CI: 4-5 days) prior to the declaration of emergency and 17 days (95% CI: 12-22 days) after.

CONCLUSION

The frequency of on-time routine childhood vaccinations was lower during the first wave of the COVID-19 pandemic. Sustained delays in routine vaccinations may lead to an increase in rates of vaccine-preventable diseases.

Nutritional Risk in Early Childhood and School Readiness

BACKGROUND

Nutrition in early childhood is important for healthy growth and development. Achieving school readiness is considered one of the most important developmental milestones for young children.

OBJECTIVES

The purpose of this study is to determine if nutritional risk in early childhood is associated with school readiness in kindergarten.

METHODS

A prospective cohort study was conducted through The Applied Research Group for Kids (TARGet Kids!) primary care research network in Toronto, Canada, 2015-2020. Nutritional risk was measured (18 mo to 5 y) using validated parent-completed questionnaires called Nutrition Screening for Toddlers and Preschoolers (NutriSTEP). High nutritional risk was categorized as scores ≥21. School readiness was measured using the validated teacher-completed Early Developmental Instrument (EDI), which measures 5 developmental domains in kindergarten (2 y of schooling, ages 4-6 y, before they enter grade 1). Vulnerability indicates scores lower than a population-based cutoff at the 10th percentile on at least 1 domain. Multiple logistic and linear regression models were conducted adjusting for relevant confounders.

RESULTS

The study included 896 children: 53% were male, 9% had high nutritional risk, and 17% were vulnerable on the EDI. A 1-SD increase in NutriSTEP total score was associated with 1.54 times increased odds of being vulnerable on the EDI among children in year 2 of kindergarten (P = 0.001). High nutritional risk cutoff was associated with 4.28 times increased odds of being vulnerable on the EDI among children in year 2 of kindergarten (P < 0.001). NutriSTEP total score and high nutritional risk were associated with lower scores on all 5 EDI domains, with the strongest association observed for the domains of language and cognitive development and communication skills and general knowledge.

CONCLUSIONS

Higher nutritional risk in early childhood is associated with lower school readiness in year 2 of kindergarten. Nutritional interventions early in life may offer opportunities to enhance school readiness. This trial was registered www.clinicaltrials.gov as NCT01869530.

Screen Use and Mental Health Symptoms in Canadian Children and Youth During the COVID-19 Pandemic

IMPORTANCE

Longitudinal research on specific forms of electronic screen use and mental health symptoms in children and youth during COVID-19 is minimal. Understanding the association may help develop policies and interventions targeting specific screen activities to promote healthful screen use and mental health in children and youth.

OBJECTIVE

To determine whether specific forms of screen use (television [TV] or digital media, video games, electronic learning, and video-chatting time) were associated with symptoms of depression, anxiety, conduct problems, irritability, hyperactivity, and inattention in children and youth during COVID-19.

DESIGN, SETTING, AND PARTICIPANTS

A longitudinal cohort study with repeated measures of exposures and outcomes was conducted in children and youth aged 2 to 18 years in Ontario, Canada, between May 2020 and April 2021 across 4 cohorts of children or youth: 2 community cohorts and 2 clinically referred cohorts. Parents were asked to complete repeated questionnaires about their children's health behaviors and mental health symptoms during COVID-19.

MAIN OUTCOMES AND MEASURES

The exposure variables were children's daily TV or digital media time, video game time, electronic-learning time, and video-chatting time. The mental health outcomes were parent-reported symptoms of child depression, anxiety, conduct problems and irritability, and hyperactivity/inattention using validated standardized tools.

RESULTS

This study included 2026 children with 6648 observations. In younger children (mean [SD] age, 5.9 [2.5] years; 275 male participants [51.7%]), higher TV or digital media time was associated with higher levels of conduct problems (age 2-4 years: β, 0.22 [95% CI, 0.10-0.35]; P < .001; age ≥4 years: β, 0.07 [95% CI, 0.02-0.11]; P = .007) and hyperactivity/inattention (β, 0.07 [95% CI, 0.006-0.14]; P = .04). In older children and youth (mean [SD] age, 11.3 [3.3] years; 844 male participants [56.5%]), higher levels of TV or digital media time were associated with higher levels of depression, anxiety, and inattention; higher levels of video game time were associated with higher levels of depression, irritability, inattention, and hyperactivity. Higher levels of electronic learning time were associated with higher levels of depression and anxiety.

CONCLUSIONS AND RELEVANCE

In this cohort study, higher levels of screen use were associated poor mental health of children and youth during the COVID-19 pandemic. These findings suggest that policy intervention as well as evidence-informed social supports are needed to promote healthful screen use and mental health in children and youth during the pandemic and beyond.