Urban environment during pregnancy, cognitive abilities, motor function, and externalizing and internalizing symptoms at 2-5 years old in 3 Canadian birth cohorts.

Background: More than 80% of the Canadian population lives in urban settings. Urban areas usually bring exposure to poorer air quality, less access to green spaces, and higher building density. These environmental factors may endanger child development.

Pets and related allergens modify the association between early life DEHP exposure and respiratory outcomes in children.

Introduction: Throughout the perinatal period children are exposed to complex mixtures, including indoor chemicals such as phthalates, and biological agents. However, few studies focus on interactions between early-life co-exposures to shed light on how co-exposures modify their individual effects. Therefore, our study aims to assess whether early-life exposure to pets and related biological agents, namely pet allergens and endotoxin, modifies the association between di-(2-ethylhexyl) phthalate (DEHP) and asthma and wheeze in preschoolers to gain insight into interactions.

Impact of postpartum hospital length of stay on infant gut microbiota: a comprehensive analysis of vaginal and caesarean birth.

Background: The primary concern with prolonged hospitalization following birth is the risk of acquiring hospital-acquired infections (HAIs) caused by opportunistic bacteria, which can alter the early establishment of gut microbiota.

Objective: To assess the association between postpartum hospital length of stay (LOS) and the composition of gut microbiota at 3 and 12 months of age according to birth mode.

Methods: In total, 1313 Canadian infants from the CHILD Cohort Study were involved in this study.

Prenatal vitamin C and fish oil supplement use are associated with human milk microbiota composition in the Canadian CHILD Cohort Study.

Maternal diet may modulate human milk microbiota, but the effects of nutritional supplements are unknown. We examined the associations of prenatal diet and supplement use with milk microbiota composition. Mothers reported prenatal diet intake and supplement use using self-administered food frequency and standardised questionnaires, respectively.

European Respiratory Society statement on preschool wheezing disorders: updated definitions, knowledge gaps and proposed future research directions.

Since the publication of the European Respiratory Society (ERS) task force reports on the management of preschool wheezing in 2008 and 2014, a large body of evidence has accumulated suggesting that the clinical phenotypes that were proposed (episodic (viral) wheezing and multiple-trigger wheezing) do not relate to underlying airway pathology and may not help determine response to treatment. Specifically, using clinical phenotypes alone may no longer be appropriate, and new approaches that can be used to inform clinical care are needed for future research. This ERS task force reviewed the literature published after 2008 related to preschool wheezing and has suggested that the criteria used to define wheezing disorders in preschool children should include age of diagnosis (0 to <6 years), confirmation of wheezing on at least one occasion, and more than one episode of wheezing ever.

Consistent cord blood DNA methylation signatures of gestational age between South Asian and white European cohorts.

Background: Epigenetic modifications, particularly DNA methylation (DNAm) in cord blood, are an important biological marker of how external exposures during gestation can influence the in-utero environment and subsequent offspring development. Despite the recognized importance of DNAm during gestation, comparative studies to determine the consistency of these epigenetic signals across different ethnic groups are largely absent. To address this gap, we first performed epigenome-wide association studies (EWAS) of gestational age (GA) using newborn cord blood DNAm comparatively in a white European (n = 342) and a South Asian (n = 490) birth cohort living in Canada.

Stress and anxiety during pregnancy and length of gestation: a federated study using data from five Canadian and European birth cohorts.

While its etiology is not fully elucidated, preterm birth represents a major public health concern as it is the leading cause of child mortality and morbidity. Stress is one of the most common perinatal conditions and may increase the risk of preterm birth. In this paper we aimed to investigate the association of maternal perceived stress and anxiety with length of gestation.

Antibiotics taken within the first year of life are linked to infant gut microbiome disruption and elevated atopic dermatitis risk.

Background: Atopic dermatitis (AD) is the most common chronic inflammatory skin disease in both pediatric and adult populations. The development of AD has been linked to antibiotic usage, which causes perturbation of the microbiome and has been associated with abnormal immune system function. However, imbalances in the gut microbiome itself associated with antibiotic usage have been inconsistently linked to AD.

The use of prescription medications and non-prescription medications during lactation in a prospective Canadian cohort study.

Background: A lack of safety data on postpartum medication use presents a potential barrier to breastfeeding and may result in infant exposure to medications in breastmilk. The type and extent of medication use by lactating women requires investigation.

Methods: Data were collected from the CHILD Cohort Study which enrolled pregnant women across Canada between 2008 and 2012.

The acute care burden of asthma in children was profoundly reduced during the COVID-19 pandemic: A multi-centre Canadian retrospective study.

Objectives: Asthma is a chronic lung condition that can be exacerbated when triggered by viruses. Pandemic public health restrictions aimed to reduce COVID-19 transmission indirectly effected other circulating viruses. This study assessed the impact of the pandemic and associated public health measures on acute paediatric asthma across four tertiary sites in three Canadian provinces.

Persistent DNA Methylation Changes across the First Year of Life and Prenatal Exposure in a Canadian Prospective Birth Study.

Background: Evidence suggests that prenatal air pollution exposure alters DNA methylation (DNAm), which could go on to affect long-term health. It remains unclear whether DNAm alterations present at birth persist through early life. Identifying persistent DNAm changes would provide greater insight into the molecular mechanisms contributing to the association of prenatal air pollution exposure with atopic diseases.

Association between Maternal Perinatal Stress and Depression on Infant DNA Methylation in the First Year of Life.

Maternal stress and depression during pregnancy and the first year of the infant's life affect a large percentage of mothers. Maternal stress and depression have been associated with adverse fetal and childhood outcomes as well as differential child DNA methylation (DNAm). However, the biological mechanisms connecting maternal stress and depression to poor health outcomes in children are still largely unknown.

Comprehensive whole-genome sequence analyses provide insights into the genomic architecture of cerebral palsy.

We performed whole-genome sequencing (WGS) in 327 children with cerebral palsy (CP) and their biological parents. We classified 37 of 327 (11.3%) children as having pathogenic/likely pathogenic (P/LP) variants and 58 of 327 (17.

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.

Association of Human Milk Fatty Acid Composition with Maternal Cardiometabolic Diseases: An Exploratory Prospective Cohort Study.

Human milk fatty acids derive from maternal diet, body stores, and mammary synthesis and may reflect women's underlying cardiometabolic health. We explored whether human milk fatty acid composition was associated with maternal cardiometabolic disease (CMD) during pregnancy and up to 5 years postpartum. We analyzed data from the prospective CHILD Cohort Study on 1,018 women with no preexisting CMD who provided breast milk samples at 3-4 months postpartum.