Early preschool wheeze trajectories are predominantly non-allergic with distinct biologic and microbiome traits.

Background: Disentangling preschool wheezing heterogeneity in terms of clinical traits, temporal patterns, and collective healthcare burden is critical for precise and effective interventions.

Objective: We aimed to collectively define contributions and distinct characteristics of respiratory phenotypes based on longitudinal wheeze and atopic sensitization patterns in the first 5 years of life.

Methods: Group-based trajectory analysis was performed in the CHILD Cohort study to identify distinct wheeze and allergic sensitization trajectories.

Divergent maturational patterns of the infant bacterial and fungal gut microbiome in the first year of life are associated with inter-kingdom community dynamics and infant nutrition.

Background: The gut microbiome undergoes primary ecological succession over the course of early life before achieving ecosystem stability around 3 years of age. These maturational patterns have been well-characterized for bacteria, but limited descriptions exist for other microbiota members, such as fungi. Further, our current understanding of the prevalence of different patterns of bacterial and fungal microbiome maturation and how inter-kingdom dynamics influence early-life microbiome establishment is limited.

Organophosphate ester flame retardants and plasticizers in house dust and mental health outcomes among Canadian mothers: A nested prospective cohort study in CHILD.

Organophosphate ester flame retardants and plasticizers (OPEs) are common exposures in modern built environments. Toxicological models report that some OPEs reduce dopamine and serotonin in the brain. Deficiencies in these neurotransmitters are associated with anxiety and depression.

Cohort profile: investigating SARS-CoV-2 infection and the health and psychosocial impact of the COVID-19 pandemic in the Canadian CHILD Cohort.

The coronavirus disease 2019 (COVID-19) pandemic has affected all Canadian families, with some impacted differently than others. Our study aims to: (1) determine the prevalence and transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection among Canadian families, (2) identify predictors of infection susceptibility and severity of SARS-CoV-2, and (3) identify health and psychosocial impacts of the COVID-19 pandemic. This study builds upon the CHILD Cohort Study, an ongoing multi-ethnic general population prospective cohort consisting of 3,454 Canadian families with children born in Vancouver, Edmonton, Manitoba, and Toronto between 2009 and 2012.

Association of COVID-19 Government-Instituted Mask Mandates With Incidence of Mask Use Among Children in Alberta, Canada.

Importance: To help prevent the spread of SARS-CoV-2, government-instituted nonpharmaceutical interventions (eg, social distancing, mask use, isolating), a provincewide government-instituted mask mandate occurred on December 8, 2020, in Alberta, Canada, although some local jurisdictions implemented an earlier mask mandate. There remains a limited understanding of the association between government-implemented public health measures and individual health behaviors of children.

Objective: To examine the association between government mask mandates and mask use among children in Alberta, Canada.

Early sex-dependent differences in metabolic profiles of overweight and adiposity in young children: a cross-sectional analysis.

Background: Childhood obesity is a global health concern and can lead to lifetime cardiometabolic disease. New advances in metabolomics can provide biochemical insights into the early development of obesity, so we aimed to characterize serum metabolites associated with overweight and adiposity in early childhood and to stratify associations by sex.

Methods: Nontargeted metabolite profiling was conducted in the Canadian CHILD birth cohort (discovery cohort) at age 5 years (n = 900) by multisegment injection-capillary electrophoresis-mass spectrometry.

Infant Vitamin D Supplements, Fecal Microbiota and Their Metabolites at 3 Months of Age in the CHILD Study Cohort.

Infant vitamin D liquid formulations often contain non-medicinal excipients such as glycerin (ie. glycerol) and 1,2-propanediol (1,2-PD). We examined whether infant vitamin D supplementation is associated with fecal glycerol and 1,2-PD concentrations at 3 months of age and characterized associations between these two molecules, and gut microbiota and their metabolites.

Natural Green Spaces, Sensitization to Allergens, and the Role of Gut Microbiota during Infancy.

The environment plays an instrumental role in the developmental origins of health and disease. Protective features of the environment in the development of asthma and atopy have been insufficiently studied. We used data from the CHILD (Canadian Healthy Infant Longitudinal Development) Cohort Study to examine relationships between living near natural green spaces in early infancy in Edmonton, AB, Canada and the development of atopic sensitization at 1 year and 3 years of age in a cohort of 699 infants, and whether these associations were mediated by infant gut microbiota (measured using 16s V4 amplicon sequencing) at 4 months.

Maturational patterns of the infant gut mycobiome are associated with early-life body mass index.

Unlike the bacterial microbiome, the role of early-life gut fungi in host metabolism and childhood obesity development remains poorly characterized. To address this, we investigate the relationship between the gut mycobiome of 100 infants from the Canadian Healthy Infant Longitudinal Development (CHILD) Cohort Study and body mass index Z scores (BMIz) in the first 5 years of life. An increase in fungal richness during the first year of life is linked to parental and infant BMI.

From Prescription Drugs to Natural Health Products: Medication Use in Canadian Infants.

Limited data exist on pharmaceutical product use by infants, although available data suggests higher prevalence of use among children under 12 months of age. We conducted a descriptive study of 3050 infants recruited in the CHILD Cohort Study, a prospective, multicenter, longitudinal cohort following children from pregnancy through childhood. Parents were surveyed for use of prescription and over-the-counter drugs, and natural health products (NHPs, including homeopathic products and vitamins) at 3, 6, and 12 months after delivery.

Prediction of odds for emergency cesarean section: A secondary analysis of the CHILD term birth cohort study.

Introduction: Previously developed cesarean section (CS) and emergency CS prediction tools use antenatal and intrapartum risk factors. We aimed to develop a predictive model for the risk of emergency CS before the onset of labour utilizing antenatal obstetric and non-obstetric factors.

Methods: We completed a secondary analysis of data collected from the CHILD Cohort Study.

Development of a Symptom-Based Tool for Screening of Children at High Risk of Preschool Asthma.

Importance: Despite advances in asthma therapeutics, the burden remains highest in preschool children; therefore, it is critical to identify primary care tools that distinguish preschool children at high risk for burdensome disease for further evaluation. Current asthma prediction tools, such as the modified Asthma Predictive Index (mAPI), require invasive tests, limiting their applicability in primary care and low-resource settings.

Objective: To develop and evaluate the use of a symptom-based screening tool to detect children at high risk of asthma, persistent wheeze symptoms, and health care burden.

The maternal prenatal and offspring early-life gut microbiome of childhood asthma phenotypes.

Background: The infant fecal microbiome is known to impact subsequent asthma risk, but the environmental exposures impacting this association, the role of the maternal microbiome, and how the microbiome impacts different childhood asthma phenotypes are unknown.

Methods: Our objective was to identify associations between features of the prenatal and early-life fecal microbiomes and child asthma phenotypes. We analyzed fecal 16 s rRNA microbiome profiling and fecal metabolomic profiling from stool samples collected from mothers during the third trimester of pregnancy (n = 120) and offspring at ages 3-6 months (n = 265), 1 (n = 436) and 3 years (n = 506) in a total of 657 mother-child pairs participating in the Vitamin D Antenatal Asthma Reduction Trial.

DNA methylation changes in cord blood and the developmental origins of health and disease - a systematic review and replication study.

Background: Environmental exposures in utero which modify DNA methylation may have a long-lasting impact on health and disease in offspring. We aimed to identify and replicate previously published genomic loci where DNA methylation changes are attributable to in utero exposures in the NutriGen birth cohort studies Alliance.

Methods: We reviewed the literature to identify differentially methylated sites of newborn DNA which are associated with the following five traits of interest maternal diabetes, pre-pregnancy body mass index (BMI), diet during pregnancy, smoking, and gestational age.

Wheeze trajectories: Determinants and outcomes in the CHILD Cohort Study.

Background: Wheezing in early life is associated with asthma in adulthood; however, the determinants of wheezing trajectories and their associations with asthma and lung function in childhood remain poorly understood.

Objective: In the CHILD Cohort Study, we aimed to identify wheezing trajectories and examine the associations between these trajectories, risk factors, and clinical outcomes at age 5 years.

Methods: Wheeze data were collected at 8 time points from 3 months to 5 years of age.

Lung clearance index predicts persistence of preschool wheeze.

Background: The lung clearance index (LCI) is a measure of pulmonary function. Variable feasibility (50->80%) in preschool children has been reported. There are limited studies exploring its relationship to respiratory symptoms and how it predicts persistent wheeze.

Development of a conceptual model of childhood asthma to inform asthma prevention policies.

Background: There is no definitive cure for asthma, as prevention remains a major goal. Decision analytic models are routinely used to evaluate the value-for-money proposition of interventions. Following best practice standards in decision-analytic modelling, the objective of this study was to solicit expert opinion to develop a concept map for a policy model for primary prevention of asthma.

Early-life cytomegalovirus infection is associated with gut microbiota perturbations and increased risk of atopy.

Background: The "old friends" hypothesis posits that reduced exposure to previously ubiquitous microorganisms is one factor involved in the increased rates of allergic diseases. Cytomegalovirus (CMV) may be one of the "old friends" hypothesized to help prevent allergic diseases. We sought to elucidate whether early-life CMV infection is associated with childhood atopy via perturbations of the gut microbiota.

Assessing secondhand and thirdhand tobacco smoke exposure in Canadian infants using questionnaires, biomarkers, and machine learning.

Background: As smoking prevalence has decreased in Canada, particularly during pregnancy and around children, and technological improvements have lowered detection limits, the use of traditional tobacco smoke biomarkers in infant populations requires re-evaluation.

Objective: We evaluated concentrations of urinary nicotine biomarkers, cotinine and trans-3'-hydroxycotinine (3HC), and questionnaire responses. We used machine learning and prediction modeling to understand sources of tobacco smoke exposure for infants from the CHILD Cohort Study.