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The EnCORE study is a prospective serology study of SARS‐CoV‐2 in a cohort of children from Montreal, Canada. Based on data from our fourth round of data collection (May–October 2022), we estimated SARS‐CoV‐2 seroprevalence and seroconversion. Using multivariable regression, we identified factors associated with seroconversion. Our results show that previously seronegative children were approximately 9–12 times more likely to seroconvert during the early Omicron‐dominant period compared to pre‐Omicron rounds. Unlike the pre‐Omicron rounds, the adjusted rate of seroconversion among 2‐ to 4‐year‐olds was higher than older age groups. As seen previously, higher seroconversion rates were associated with ethnic/racial minority status. [ABSTRACT FROM AUTHOR]

Introduction: Sex differences exist in children’s obesity rates, dietary patterns and television viewing. Television continues to be a source of unhealthy food advertising exposure to children in Canada. Our objective was to examine sex differences in food advertising exposure in children aged 2 to 17 years across four Canadian Englishlanguage markets. Methods: We licensed 24-hour television advertising data from the company Numerator for January through December 2019, in four cities (Vancouver, Calgary, Montréal and Toronto) across Canada. Child food advertising exposure overall, by food category, television station, Health Canada’s proposed nutrient profiling model, and marketing techniques were examined on the 10 most popular television stations among children and compared by sex. Advertising exposure was estimated using gross rating points, and sex differences were described using relative and absolute differences. Results: Both male and female children were exposed to an elevated level of unhealthy food advertising and a plethora of marketing techniques across all four cities. Differences between sexes were evident between and within cities. Compared to females, males in Vancouver and Montréal viewed respectively 24.7% and 24.0% more unhealthy food ads/person/year and were exposed to 90.2 and 133.4 more calls to action, 93.3 and 97.8 more health appeals, and 88.4 and 81.0 more products that appeal to children. Conclusion: Television is a significant source of children’s exposure to food advertising, with clear sex differences. Policy makers need to consider sex when developing food advertising restrictions and monitoring efforts. [ABSTRACT FROM AUTHOR]

Child and adolescent student athletes with attention-deficit/hyperactivity disorder (ADHD) report a greater lifetime history of concussion than those without ADHD. This case-control study compared youth with and without ADHD presenting for care at a specialty concussion clinic on their lifetime history of concussion. We hypothesized that a greater proportion of youth with ADHD would report a history of prior concussion. Archival clinical data from patients presenting to a specialty concussion clinic in Montreal, Québec, Canada between September 2015 and August 2019 were analyzed. The sample included 2,418 children and adolescents (age: M = 13.6, SD = 2.7, range 5–18 years; 50.9% girls), including 294 (12.2%) with ADHD and 2,124 (87.8%) without ADHD. The proportion with prior concussion among youth with ADHD (43.9%) was significantly greater than youth without ADHD [37.5%, χ2 = 4.41, p = 0.04, OR = 1.30, 95% confidence interval (CI): 1.02–1.67]. A significantly higher proportion of boys with ADHD had a prior concussion history (48.1%) than boys without ADHD [38.4%, χ2 = 5.33, p = 0.02, OR = 1.48 (95% CI: 1.06–2.09)], but this difference was not observed for girls (χ2 = 0.31, p = 0.58). Youth with ADHD did not differ with regard to their estimated longest duration of symptoms from a prior concussion (Z = 1.52, p = 0.13) and the proportion who reported taking longer than 28 days to recover from a prior concussion did not differ between those with ADHD (15.3%) and without ADHD (12.2%), χ2 = 2.20, p = 0.14. Among youth presenting to a specialty clinic, ADHD was associated with greater lifetime history of concussion but not a greater duration of symptoms from a prior injury. [ABSTRACT FROM AUTHOR]

Background: Vitamin D status at birth is reliant on maternal-fetal transfer of vitamin D during gestation.Objectives: We aimed to examine the vitamin D status of newborn infants in a diverse population and to subsequently identify the modifiable correlates of vitamin D status.Methods: In this cross-sectional study, healthy mother-infant dyads (n = 1035) were recruited within 36 h after term delivery (March 2016-March 2019). Demographic and lifestyle factors were surveyed. Newborn serum 25-hydroxyvitamin D [25(OH)D] was measured (standardized chemiluminescence immunoassay) and categorized as deficient [serum 25(OH)D <30 nmol/L] or adequate (≥40 nmol/L). Serum 25(OH)D was compared among categories of maternal characteristics using ANOVA; each characteristic was tested in a separate model. Subgroups (use of multivitamins preconception and continued in pregnancy compared with during pregnancy only) were matched (n = 352/group) for maternal factors (ancestry, age, income, education, parity, and prepregnancy BMI) using propensity scores; logistic regression models were generated for odds of deficiency or adequacy.Results: Infants' mean serum 25(OH)D was 45.9 nmol/L (95% CI: 44.7, 47.0 nmol/L) (n = 1035), with 20.8% (95% CI: 18.3%, 23.2%) deficient and 60.7% (95% CI: 55.2%, 66.2%) adequate. Deficiency prevalence ranged from 14.6% of white infants to 41.7% of black infants. Serum 25(OH)D was higher (P < 0.0001) in infants of mothers with higher income, BMI < 25 kg/m2, exercise and sun exposure in pregnancy, and use of multivitamins preconception. In the matched-subgroup analysis, multivitamin supplementation preconception plus during pregnancy relative to only during pregnancy was associated with lower odds for vitamin D deficiency (ORadj: 0.55; 95% CI: 0.36, 0.86) and higher odds for adequate vitamin D status (ORadj: 1.47; 95% CI: 1.04, 2.07).Conclusions: In this study most newborn infants had adequate vitamin D status, yet one-fifth were vitamin D deficient with disparities between population groups. Guidelines for a healthy pregnancy recommend maternal use of multivitamins preconception and continuing in pregnancy. An emphasis on preconception use may help to achieve adequate neonatal vitamin D status.This trial was registered at clinicaltrials.gov as NCT02563015. [ABSTRACT FROM AUTHOR]

Objective: To quantify food/beverage advertising on television in Montreal (Quebec), to estimate and characterise children's exposure and to examine trends over time.Design: Television food advertising data were licensed for nineteen food categories and eighteen stations for May 2011, 2016 and 2019. The frequency of advertisements and the average number viewed per child aged 2-11 years overall, by food category and by station type (i.e. youth-appealing (n 3) and generalist (n 15) stations) were determined. The percent change in advertising frequency and exposure between May 2011 and 2019 was calculated.Setting: Montreal, Quebec, Canada.Participants: This study used media data and did not directly involve human participants.Results: The total number of television advertisements increased by 11 % between May 2011 (n 41 084) and May 2019 (n 45 406); however, exposure to food/beverage advertisements decreased by 53 %, going from 226 ads/child in May 2011 to 107 ads/child in May 2019. Overall, the most advertised food categories in both May 2011 and 2019 were fast food (29·8 % and 39·2 %, respectively) followed by chocolate (14·2 %) in 2011 and savory snacks (9·7 %) in 2019. In May 2019, children were predominantly exposed to unhealthy food categories such as fast food (41·3 % of exposure), savory snacks (7·5 %), chocolate (5·0 %) and regular soft drinks (4·5 %), and most (89·3 %) of their total exposure occurred on generalist television stations.Conclusion: Despite Quebec's restrictions on commercial advertising directed to children under 13 years, Quebecois children are still frequently exposed to unhealthy food advertising on television. Government should tighten restrictions to protect children from this exposure. [ABSTRACT FROM AUTHOR]

Despite many children experiencing fatigue after childhood brain injury, little is known about the predictors of this complaint. To date, traditional indices of traumatic brain injury (TBI) severity have not predicted reliably persisting fatigue (up to three years post-injury). This study aimed to establish whether persisting fatigue is predicted by serum biomarker concentrations in child TBI. We examined whether acute serum biomarker expression would improve prediction models of 12-month fatigue based on injury severity. Blood samples were collected from 87 children (1–17 years at injury) sustaining mild to severe TBI (Glasgow Coma Scale [GCS] range 3–15; mean 12.43; classified as mild TBI [n = 50, 57%] vs. moderate/severe TBI [n = 37, 43%]), and presenting to the emergency departments (ED) and pediatric intensive care units (PICU) at one of three tertiary pediatric hospitals (Royal Children's Hospital (RCH); Hospital for Sick Children (HSC), Toronto; St Justine Children's Hospital (SJH), Montreal). Six serum biomarker concentrations were measured within 24 h of injury (interleukin-6, interleukin-8 [IL-8], soluble vascular cell adhesion molecule [SVCAM], S100 calcium binding protein B [S100B], neuron specific enolase [NSE], and soluble neural cell adhesion molecule [sNCAM]). Fatigue at 12 months post-injury was measured using the Pediatric Quality of Life Inventory Multidimensional Fatigue Scale (parent report), classified as present/absent using previously derived cut-points. At 12 months post-injury, 22% of participants experienced fatigue. A model including IL-8 was the best serum biomarker for estimating the probability of children experiencing fatigue at 12 months post-injury. The IL-8 also significantly improved predictive models of fatigue based on severity. [ABSTRACT FROM AUTHOR]

Whether families with children choose to live in the suburbs to benefit from cheap land or do so to avoid decaying socio-economic conditions of central neighbourhoods remains a central question for public policy. To explore that question, this article investigates the characteristics of communities within the Montreal metropolitan area where families with children have chosen to live (108 communities). Three different analyses are undertaken. The first analysis is a community-based estimation of the Alonso model. It shows that the average price of a single-family house within a community varies with distance to the Central Business District (CBD), and that space per household for housing grows in relation with distance. The second analysis is inspired by life-cycle arguments. It shows that housing space is not as significant as new housing development or poverty to explain the proportion of families with children in communities of the metropolitan area. The third analysis, using data pertaining to families with children only, shows that communities closer to the CBD have a higher proportion of low-income families as well as high-income ones. These communities also have a higher proportion of families with parents that are immigrants, have university degrees, are single (divorced), and are under 35 years old. Mothers are also more likely to be active in these communities. We conclude that developing homogenous neighbourhoods designed for upper-middle-class households and knowledge-based workers may better contribute to the attraction of families with children in Montreal’s central neighbourhoods than building affordable housing. [ABSTRACT FROM AUTHOR]

Introduction: Research has shown that during the 2003 SARS pandemic, emergency department (ED) visits among the pediatric population decreased. We set out to investigate if this was also true for injury-related ED visits during the COVID-19 pandemic. Methods: Using data from the Canadian Hospitals Injury Reporting and Prevention Program (CHIRPP), we looked at 28 years of injury-related ED visits at the Montreal Children's Hospital, a provincially designated Pediatric Trauma Centre. We compared data from a two-month period during the COVID-19 lockdown (16 March to 15 May) to the same period in previous years (1993-2019) to determine whether the 2020 decrease in ED visit numbers was unprecedented (i.e. a similar decrease had never occurred) for different age groups, nature of injuries, mechanisms and severity. Results: The 2020 decrease was unprecedented across all age groups between 1993 and 2019. When compared with the 2015 to 2019 average, the decrease was smallest in children aged 2 to 5 years (a 35% decrease), and greatest in the group aged 12 to 17 years (83%). Motor vehicle collisions and sports-related injuries practically vanished during the COVID-19 lockdown. Surprisingly, more children aged 6 to 17 years presented with less urgent injuries during the COVID-19 lockdown than in previous years. Conclusion: As was the case with SARS in 2003, COVID-19 acted as a deterrent for pediatric ED visits. The lockdown in particular had a profound impact on injury-related visits. The de-confinement period will be monitored to determine the impact in both the short and the long term. [ABSTRACT FROM AUTHOR]

Introduction: La Maison Bleue is a community-based perinatal health and social centre in Montreal that provides services during pregnancy up to age five to families living in vulnerable contexts. The study aimed to describe: 1) the challenges and protective factors that affect the well-being of migrant families receiving care at La Maison Bleue; and 2) how La Maison Bleue strengthens resilience among these families. Methods: We conducted a focused ethnography. Immigrants, refugees, asylum seekers and undocumented migrants were invited to participate. We collected data from November to December 2017 via semi-structured interviews and participant observation during group activities at La Maison Bleue. Data were thematically analysed. Results: Twenty-four mothers participated (9 interviewed, 17 observed). Challenges to well-being included family separation, isolation, loss of support, the immigration process, an unfamiliar culture and environment, and language barriers. Key protective factors were women’s intrinsic drive to overcome difficulties, their positive outlook and ability to find meaning in their adversity, their faith, culture and traditions, and supportive relationships, both locally and transnationally. La Maison Bleue strengthened resilience by providing a safe space, offering holistic care that responded to both medical and psychosocial needs, and empowering women to achieve their full potential towards better health for themselves and their families. Conclusion: Migrant mothers have many strengths and centres like La Maison Bleue can offer a safe space and be an empowering community resource to assist mothers in overcoming the multiple challenges that they face while resettling and raising their young children in a new country. [ABSTRACT FROM AUTHOR]

Background: Killer-cell Immunoglobulin-like Receptor (KIR) genes encode receptors, which are mainly expressed on, and control functional activities of, Natural Killer (NK) cells. There exist six distinct activating KIR genes in humans, who differ from one another with respect to the repertoire of these genes. Because activated NK cells can potentially cause tissue destruction, we hypothesized that variation in the inherited activating KIR genes in humans is associated with their innate susceptibility/resistance to developing Crohn disease (CD). Methods: We performed case control studies on three independent Canadian CD patient cohorts (all of the Western European descent): two comprising children (Montreal having 193 cases and 245 controls, and Ottawa having 93 cases and 120 controls) and the third one comprising predominantly adults (Winnipeg having 164 cases and 200 controls). We genotyped cases and controls for activating KIR genes by PCR with gene-specific primers and investigated associations between the genes and cases using unconditional logistic regression. Results: We observed strong associations between all the six KIR genes and CD in Ottawa children, with the strongest risk observed for the KIR2DS1 (p = 1.7 x10-10). Associations between all but the KIR2DS2 were replicated in the Montreal cohort with the strongest association evident for the KIR2DS5 (8.0 x 10−10). Similarly associations between five genes were observed in the adult Winnipeg cohort. In this cohort, strongest associations were evident with the KIR2DS5 (8.75 x 10−8). An overall analysis for all cohorts showed strong associations with four of the genes, with the strongest association evident for the KIR2DS5 (p = 1.35 x 10−17). In the combined analysis for four KIR genes, individuals carrying one or more of the KIR genes were at significantly higher risks for acquiring CD (p = 3.5 x 10−34). Conclusions: Activating KIR genes are associated with risk for developing CD in both children and adults. [ABSTRACT FROM AUTHOR]

A focused ethnography was conducted in an after-school academic support program serving vulnerable populations in Montreal, Quebec, Canada. The aim of this study was to explore the moral experiences of children living in poverty to inform on their daily experiences and moral lives. Our results highlighted that these children, who were experiencing economic hardship and/or social isolation, faced various social barriers, such as stigmatization, family isolation, and linguistic challenges for new immigrant children. As active agents, they navigated the challenges they encountered with help from the program. [ABSTRACT FROM AUTHOR]

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BACKGROUND: Little is known about the respiratory effects of short-term exposures to petroleum refinery emissions in young children. This study is an extension of an ecologic study that found an increased rate of hospitalizations for respiratory conditions among children living near petroleum refineries in Montreal (Canada). METHODS: We used a time-stratified case--crossover design to assess the risk of asthma episodes in relation to short-term variations in sulfur dioxide levels among children 2--4 years of age living within 0.5--7.5 km of the refinery stacks. Health data used to measure asthma episodes included emergency department (ED) visits and hospital admissions from 1996 to 2004. We estimated daily levels of SO2 at the residence of children using a) two fixed-site SO2 monitors located near the refineries and b) the AERMOD (American Meteorological Society/Environmental Protection Agency Regulatory Model) atmospheric dispersion model. We used conditional logistic regression to estimate odds ratios associated with an increase in the interquartile range of daily SO2 mean and peak exposures (31.2 ppb for AERMOD peaks). We adjusted for temperature, relative humidity, and regional/urban background air pollutant levels. RESULTS: The risks of asthma ED visits and hospitalizations were more pronounced for same-day (lag 0) SO2 peak levels than for mean levels on the same day, or for other lags: the adjusted odds ratios estimated for same-day SO2 peak levels from AERMOD were 1.10 [95% confidence interval (CI), 1.00--1.22] and 1.42 (95% CI, 1.10--1.82), over the interquartile range, for ED visits and hospital admissions, respectively. CONCLUSIONS: Short-term episodes of increased SO2 exposures from refinery stack emissions were associated with a higher number of asthma episodes in nearby children. [ABSTRACT FROM AUTHOR]