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).

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.

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).

Paternal BMI in the preconception period, and the association with child zBMI.

BACKGROUND: Rapid growth and excess weight in early childhood are associated with obesity risk. While maternal preconception BMI has been identified as a potential risk factor, the role of paternal preconception BMI is less clear. OBJECTIVES: To examine the association between paternal preconception BMI and age- and sex-standardized WHO BMI z-score (zBMI) growth rates, zBMI, and weight status, in 0- to 10-year-old children. To determine whether these associations differed by child sex and maternal preconception weight status. METHODS: A longitudinal cohort study was conducted through The Applied Research Group for Kids (TARGet Kids!). Children (n = 218) underwent repeated measures of height and weight from birth to 10 years old. Piecewise linear mixed models were used to assess the association between paternal preconception BMI and child zBMI growth rates (zBMI SD units/month) between 0, 4, 30, 48 and 120 months of age. Linear mixed models were used to examine the association with child zBMI, and logistic generalized estimation equations (GEE) were used to assess the association with child weight status. Child sex and maternal preconception weight status were tested as effect modifiers. RESULTS: Paternal preconception BMI was associated with child zBMI growth rate, mean zBMI and weight status in boys, but not girls. A 5 kg/m2 higher paternal preconception BMI was associated with approximately 0.01 zBMI SD unit/month higher growth rate for boys born to mothers with preconception overweight. Higher paternal BMI was associated with higher mean zBMI and increased odds of overweight and obesity in boys, with greater effects seen when mothers had preconception overweight compared to normal weight. CONCLUSION: Paternal preconception BMI was associated with child zBMI growth rate, zBMI and weight status in boys, with greater effects when the biological mother had preconception overweight or obesity. Further understanding of sex differences in paternal preconception weight effects in children is needed.

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.

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.

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.

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.

Timing of Introduction to Solid Food, Growth, and Nutrition Risk in Later Childhood.

OBJECTIVE: To evaluate the relationship between the timing of infant cereal introduction between 4 and 6 months of age and growth and dietary intake in later childhood. STUDY DESIGN: A longitudinal cohort study was conducted among healthy children 0-10 years of age participating in The Applied Research Group for Kids cohort study between June 2008 and August 2019 in Toronto, Canada. RESULTS: Of 8943 children included, the mean (SD) age of infant cereal introduction was 5.7 (2.1) months. In the primary analysis, children who were introduced to infant cereal at 4 vs 6 months had 0.17 greater body mass index z score (95% CI 0.06-0.28; P = .002) and greater odds of obesity (OR 1.82; 95% CI 1.18-2.80; P = .006) at 10 years of age. In the secondary analysis, children who were introduced to infant cereal at 4 vs 6 months had 0.09 greater height-for-age z score (95% CI 0.04-0.15; P = .002) at 1 year of age, an association that was not observed at 5 or 10 years of age. Children who were introduced to infant cereal at 4 vs 6 months had greater nutrition risk which was primarily determined by a less-favorable eating behavior score at 18 months to 5 years of age (0.18 units higher; 95% CI 0.07-0.29; P = .001). CONCLUSIONS: Introduction of infant cereal at 4 vs 6 months was associated with greater body mass index z score, greater odds of obesity, similar height-for-age z score, and less favorable eating behavior. These findings support recommendations for introducing solid food around 6 months of age.

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.

Cow's milk fat and child adiposity: a prospective cohort study.

BACKGROUND: International guidelines recommend children aged 9 months to 2 years consume whole (3.25%) fat cow's milk, and children older than age 2 years consume reduced (0.1-2%) fat cow's milk to prevent obesity. The objective of this study was to evaluate the longitudinal relationship between cow's milk fat (0.1-3.25%) intake and body mass index z-score (zBMI) in childhood. We hypothesized that higher cow's milk fat intake was associated with lower zBMI. METHODS: A prospective cohort study of children aged 9 months to 8 years was conducted through the TARGet Kids! primary care research network. The exposure was cow's milk fat consumption (skim (0.1%), 1%, 2%, whole (3.25%)), measured by parental report. The outcome was zBMI. Height and weight were measured by trained research assistants and zBMI was determined according to WHO growth standards. A linear mixed effects model and logistic generalized estimating equations were used to determine the longitudinal association between cow's milk fat intake and child zBMI. RESULTS: Among children aged 9 months to 8 years (N = 7467; 4699 of whom had repeated measures), each 1% increase in cow's milk fat consumed was associated with a 0.05 lower zBMI score (95% CI -0.07 to -0.03, p < 0.0001) after adjustment for covariates including volume of milk consumed. Compared to children who consumed reduced fat (0.1-2%) milk, there was evidence that children who consumed whole milk had 16% lower odds of overweight (OR = 0.84, 95% CI 0.77 to 0.91, p < 0.0001) and 18% lower odds of obesity (OR = 0.82, 95% CI 0.68 to 1.00, p = 0.047). CONCLUSIONS: Guidelines for reduced fat instead of whole cow's milk during childhood may not be effective in preventing overweight or obesity.

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.

Associations Between Meeting the 24-Hour Movement Guidelines and Cardiometabolic Risk in Young Children.

INTRODUCTION: The authors aimed to examine the association between meeting the integrative movement behavior guidelines (physical activity, screen viewing, and sleep) and cardiometabolic risk (CMR) factors in young children. METHODS: In this cross-sectional study, physical activity, screen viewing, and sleep were assessed using parent-reported data. The 24-Hour Movement Guidelines for the Early Years (0-4 y) were defined as 180 minutes of physical activity/day (of which ≥60 min should be moderate-to-vigorous intensity), ≤1 hour of screen viewing/day, and 10 to 13 hours of sleep/night. Waist circumference, glucose, high-density lipoprotein cholesterol, triglycerides, and systolic blood pressure were measured in a clinical setting by trained staff. A total CMR score and individual CMR factors served as primary and secondary outcomes, respectively. RESULTS: Of the 767 participants (3-4 y), 26.4% met none of the guideline's recommendations, whereas 41.3%, 33.1%, and 10.6% of the sample met 1, 2, or all 3 recommendations, respectively. The number of recommendations met was not associated with the total CMR score or individual CMR factors (P > .05), with the exceptions of high-density lipoprotein (odds ratio = 1.61; 95% confidence interval, 1.11 to 2.33; P = .01). CONCLUSION: Meeting the 24-Hour Movement Guidelines in early childhood was not associated with overall CMR, but was associated with favorable cholesterol outcomes.

The association between screen time and cardiometabolic risk in young children.

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

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.

RéSUMé: OBJECTIF: Examiner les facteurs associés à la vaccination contre la COVID-19 (délai de vaccination et statut vaccinal) chez de jeunes enfants en bonne santé recevant des soins de santé primaires. MéTHODE: Une étude de cohorte a été menée entre novembre 2021 et septembre 2022 par le réseau de recherche en soins primaires TARGet Kids! à Toronto, au Canada. Des données sur le profil sociodémographique, les caractéristiques de santé des enfants et des parents, les convictions parentales à l'égard de la vaccination et la vaccination des enfants contre la COVID-19 ont été recueillies au moyen de questionnaires remplis par les parents. Le résultat principal était le délai de vaccination des enfants contre la COVID-19, mesuré comme étant le temps écoulé entre la date de disponibilité d'un vaccin et la date de vaccination de l'enfant contre la COVID-19 déclarée par le parent. Des modèles de risques proportionnels censurés par intervalle ont été utilisés. RéSULTATS: En tout, 267 enfants de 0 à 13 ans ont été inclus. Ils avaient 7,6 ans en moyenne, 52,8% (n = 141) étaient des garçons, 66,5% (n = 141) avaient une mère d'origine ethnique européenne (avec des données manquantes), et 68,2% (n = 182) étaient vaccinés. Tous les parents des enfants vaccinés étaient eux-mêmes vaccinés contre la COVID-19. Le taux de vaccination des enfants augmentait de 2 % pour chaque mois d'augmentation de l'âge des enfants (rapport de risques instantanés [RRI] ajusté = 1,02, intervalle de confiance [IC] de 95% = 1,01­1,03, p < 0,001). Comparativement aux enfants dont les parents étaient incertains dans leurs convictions, ceux dont les parents croyaient en l'importance et en l'innocuité de la vaccination contre la COVID-19 pour leurs enfants avaient des taux de vaccination plus élevés (RRI ajusté = 8,29, IC de 95% = 4,25­16,17, p < 0,001; RRI ajusté = 5,09, IC de 95% = 3,17­8,17, p < 0,001). CONCLUSION: L'âge plus avancé des enfants, la vaccination parentale contre la COVID-19 et les convictions parentales positives à l'égard de la vaccination contre la COVID-19 présentaient une corrélation significative avec la vaccination contre la COVID-19 chez les jeunes enfants en bonne santé. Nos constats pourraient contribuer à éclairer les politiques, les pratiques et la recherche visant à renforcer la confiance parentale en la vaccination et à promouvoir la vaccination des enfants contre la COVID-19.

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.

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.

Changes in sleep and the prevalence of probable insomnia in undergraduate university students over the course of the COVID-19 pandemic: findings from the U-Flourish cohort study.

BACKGROUND: Sleep problems associated with poor mental health and academic outcomes may have been exacerbated by the COVID-19 pandemic. AIMS: To describe sleep in undergraduate students during the COVID-19 pandemic. METHOD: This longitudinal analysis included data from 9523 students over 4 years (2018-2022), associated with different pandemic phases. Students completed a biannual survey assessing risk factors, mental health symptoms and lifestyle, using validated measures. Sleep was assessed with the Sleep Condition Indicator (SCI-8). Propensity weights and multivariable log-binomial regressions were used to compare sleep in four successive first-year cohorts. Linear mixed-effects models were used to examine changes in sleep over academic semesters and years. RESULTS: There was an overall decrease in average SCI-8 scores, indicating worsening sleep across academic years (average change -0.42 per year; P-trend < 0.001), and an increase in probable insomnia at university entry (range 18.1-29.7%; P-trend < 0.001) before and up to the peak of the pandemic. Sleep improved somewhat in autumn 2021, when restrictions loosened. Students commonly reported daytime sleep problems, including mood, energy, relationships (36-48%) and concentration, productivity, and daytime sleepiness (54-66%). There was a consistent pattern of worsening sleep over the academic year. Probable insomnia was associated with increased cannabis use and passive screen time, and reduced recreation and exercise. CONCLUSIONS: Sleep difficulties are common and persistent in students, were amplified by the pandemic and worsen over the academic year. Given the importance of sleep for well-being and academic success, a preventive focus on sleep hygiene, healthy lifestyle and low-intensity sleep interventions seems justified.

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.

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.