Mode of delivery and birth outcomes before and during COVID-19 -A population-based study in Ontario, Canada.

There is lack of clarity on whether pregnancies during COVID-19 resulted in poorer mode of delivery and birth outcomes in Ontario, Canada. We aimed to compare mode of delivery (C-section), birth (low birthweight, preterm birth, NICU admission), and health services use (HSU, hospitalizations, ED visits, physician visits) outcomes in pregnant Ontario women before and during COVID-19 (pandemic periods). We further stratified for pre-existing chronic diseases (asthma, eczema, allergic rhinitis, diabetes, hypertension). Deliveries before (Jun 2018-Feb 2020) and during (Jul 2020-Mar 2022) pandemic were from health administrative data. We used multivariable logistic regression analyses to estimate adjusted odds ratios (aOR) of delivery and birth outcomes, and negative binomial regression for adjusted rate ratios (aRR) of HSU. We compared outcomes between pre-pandemic and pandemic periods. Possible interactions between study periods and covariates were also examined. 323,359 deliveries were included (50% during pandemic). One in 5 (18.3%) women who delivered during the pandemic had not received any COVID-19 vaccine, while one in 20 women (5.2%) lab-tested positive for COVID-19. The odds of C-section delivery during the pandemic was 9% higher (aOR = 1.09, 95% CI: 1.08-1.11) than pre-pandemic. The odds of preterm birth and NICU admission were 15% (aOR = 0.85, 95% CI: 0.82-0.87) and 10% lower (aOR = 0.90, 95% CI: 0.88-0.92), respectively, during COVID-19. There was a 17% reduction in ED visits but a 16% increase in physician visits during the pandemic (aRR = 0.83, 95% CI: 0.81-0.84 and aRR = 1.16, 95% CI: 1.16-1.17, respectively). These aORs and aRRs were significantly higher in women with pre-existing chronic conditions. During the pandemic, healthcare utilization, especially ED visits (aRR = 0.83), in pregnant women was lower compared to before. Ensuring ongoing prenatal care during the pandemic may reduce risks of adverse mode of delivery and the need for acute care during pregnancy.

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.

Recurrent Intensive Care Episodes and Mortality Among Children With Severe Neurologic Impairment.

Importance: Children requiring care in a pediatric intensive care unit (PICU) are known to have increased risk of subsequent mortality. Children with severe neurologic impairment (SNI)-who carry neurologic or genetic diagnoses with functional impairments and medical complexity-are frequently admitted to PICUs. Although recurrent PICU critical illness episodes (PICU-CIEs) are assumed to indicate a poor prognosis, the association between recurrent PICU-CIEs and mortality in this patient population is poorly understood. Objective: To assess the association between number of recent PICU-CIEs and survival among children with severe neurologic impairment. Design, Setting, and Participants: This population-based retrospective cohort study used health administrative data from April 1, 2002, to March 31, 2020, on 4774 children born between 2002 and 2019 with an SNI diagnosis code in an Ontario, Canada, hospital record before 16 years of age and a first PICU-CIE from 2002 to 2019. Data were analyzed from November 2021 to June 2023. Exposure: Pediatric intensive care unit critical illness episodes (excluding brief postoperative PICU admissions). Main Outcome and Measures: One-year survival conditioned on the number and severity (length of stay >15 days or use of invasive mechanical ventilation) of PICU-CIEs in the preceding year. Results: In Ontario, 4774 children with SNI (mean [SD] age, 2.1 [3.6] months; 2636 [55.2%] <1 year of age; 2613 boys [54.7%]) were discharged alive between 2002 and 2019 after their first PICU-CIE. Ten-year survival after the initial episode was 81% (95% CI, 79%-82%) for children younger than 1 year of age and 84% (95% CI, 82%-86%) for children 1 year of age or older; the age-stratified curves converged by 15 years after the initial episode at 79% survival (95% CI, 78%-81% for children <1 year and 95% CI, 75%-84% for children ≥1 year). Adjusted for age category and demographic factors, the presence of nonneurologic complex chronic conditions (adjusted hazard ratio [AHR], 1.70 [95% CI, 1.43-2.02]) and medical technology assistance (AHR, 2.32 [95% CI, 1.92-2.81]) were associated with increased mortality. Conditional 1-year mortality was less than 20% regardless of number or severity of recent PICU-CIEs. Among children with high-risk PICU-CIEs, 1-year conditional survival decreased from 90% (95% CI, 89%-91%) after the first PICU-CIE to 81% (95% CI, 77%-86%) after the fourth PICU-CIE. Conclusions and Relevance: This cohort study of children with SNI demonstrated a modest dose-dependent association between PICU-CIEs and short-term mortality. These data did not support the conventional wisdom that recurrent PICU admissions are associated with subsequent high mortality risk.

Association of ever use of e-cigarettes with health and lifestyle variables among young adults: a Canadian health measure survey study.

Research suggests that vaping raises oxidative stress levels and has been implicated in poor mental health. The objective of this study is to assess cross-sectional associations between quality of life (QOL) indicators and e-cigarette (EC) use in young Canadian adults. We used data from the 2016-2017 Canadian Health Measures Survey. We compared physical activity (daily steps), physiological measurements (high-density lipoprotein for cholesterol level), self-perceived life stress, mental health, and QOL between ever-use EC users and non-users. Multivariable binary or ordinal logistic regressions were used to calculate odds ratios (OR) with 95% confidence intervals (CI). Analyses included 905 participants (15-30 years) with 115 (12.7%) reporting EC use and 790 non-users. After adjusting for confounders, compared to non-users, EC users had significantly higher odds of being physically active (OR = 2.19, 95%CI: 1.14-4.20) but also with self-reported extreme life stress (OR = 2.68, 95%CI: 1.45-4.92). Albeit statistically non-significant, EC users also had higher odds of poorer QOL (OR = 1.12, 95%CI: 0.64-1.95). No statistically significant interactions between EC use, cigarette smoking, cannabis consumption and health outcomes were observed. CONCLUSION: Our study found that EC use was independently and significantly associated with increased odds of life stress and an indication of poorer QOL. Ongoing surveillance on young EC users is important to measure the long-term impact of vaping on their physical, mental health and quality of life to target for interventions. WHAT IS KNOWN: • E-cigarette use has been associated with high-risk behaviours and adverse mental health outcomes, such as depression and anxiety. WHAT IS NEW: • E-cigarette users had significantly higher odds of being physically active and higher amounts of life stress.

Vaping and Health Service Use: A Canadian Health Survey and Health Administrative Data Study.

Rationale: Emerging research suggests that e-cigarette (EC) use may have detrimental health effects, increasing the burden on healthcare systems. Objectives: To determine whether young EC users had increased asthma, asthma attacks, and health services use (HSU). Methods: This cohort study used the linked Canadian Community Health Survey (cycles 2015-16 and 2017-18) and health administrative data (January 2015-March 2018). A propensity score method matched self-reported EC users to up to five control subjects. Matched multivariable logistic and negative binomial regressions were used to calculate odds ratios, rate ratios (RRs), and 95% confidence intervals (CIs) with EC use as the exposure and asthma, asthma attacks, and all-cause HSU as the outcomes. Results: Analyses included 2,700 matched Canadian Community Health Survey participants (15-30 yr), 505 (2.4% of 20,725 participants) EC users matched to 2,195 nonusers. After adjusting for confounders, EC users with asthma had over twofold higher odds of having an asthma attack in the last 12 months (odds ratio, 2.30; 95% CI, 1.29-4.12). Dual EC and conventional tobacco users had a twofold increased all-cause HSU rate compared with nonusers who never smoked tobacco (RR, 2.13; 95% CI, 1.53-2.98). This rate was greater than that for EC users who never smoked tobacco (RR, 1.73; 95% CI, 1.00-3.00) and non-EC users who regularly smoke tobacco (RR, 1.72; 95% CI, 1.29-2.29). Compared with male nonusers, female EC users had the highest increased all-cause HSU (RR, 1.94; 95% CI, 1.39-2.69) over male EC users and female nonusers (RR, 1.13; 95% CI, 0.86-1.48; RR, 1.41; 95% CI, 1.16-1.71, respectively). Conclusions: Current EC use is associated with significantly increased odds of having an asthma attack. Furthermore, concurrent EC use and conventional cigarette smoking are associated with a higher rate of all-cause HSU. The odds of asthma attack and all-cause HSU were highest among women. Thus, EC use may be an epidemiological biomarker for youth and young adults with increased health morbidity.

Healthcare utilization in Canadian children and young adults with asthma during the COVID-19 pandemic.

Literature is limited regarding the COVID-19 pandemic's impact on health services use in younger Canadian populations with asthma. We utilized health administrative databases from January 2019-December 2021 for a population-based cross-sectional study to identify Ontario residents 0-25 years old with physician-diagnosed asthma and calculate rates of healthcare use. Multivariable negative binomial regression analysis was used to adjust for confounders. We included 716,690 children and young adults ≤25 years. There was a sharp increase of ICS and SABA prescription rates at the start of the pandemic (March 2020) of 61.7% and 54.6%, respectively. Monthly virtual physician visit rates increased from zero to 0.23 per 100 asthma population during the pandemic. After adjusting for potential confounders, rate ratios (RR) with 95% confidence intervals (CI) showed that the pandemic was associated with significant decrease in hospital admissions (RR = 0.21, 95% CI: 0.18-0.24), emergency department visits (RR = 0.35, 95% CI: 0.34-0.37), and physician visits (RR = 0.61, 95% CI: 0.60-0.61). ICS and SABA prescriptions filled also significantly decreased during the pandemic (RR = 0.58, 95% CI: 0.57-0.60 and RR = 0.47, 95% CI: 0.46-0.48, respectively). This Canadian population-based asthma study demonstrated a dramatic decline in physician and emergency department visits, hospitalizations, and medication prescriptions filled during the COVID-19 pandemic. An extensive evaluation of the factors contributing to an 80% reduction in the risk of hospitalization may inform post-pandemic asthma management.

Does early life exposure to exogenous sources of reactive oxygen species (ROS) increase the risk of respiratory and allergic diseases in children? A longitudinal cohort study.

BACKGROUND: Excess reactive oxygen species (ROS) can cause oxidative stress damaging cells and tissues, leading to adverse health effects in the respiratory tract. Yet, few human epidemiological studies have quantified the adverse effect of early life exposure to ROS on child health. Thus, this study aimed to examine the association of levels of ROS exposure at birth and the subsequent risk of developing common respiratory and allergic diseases in children. METHODS: 1,284 Toronto Child Health Evaluation Questionnaire (T-CHEQ) participants were followed from birth (born between 1996 and 2000) until outcome, March 31, 2016 or loss-to-follow-up. Using ROS data from air monitoring campaigns and land use data in Toronto, ROS concentrations generated in the human respiratory tract in response to inhaled pollutants were estimated using a kinetic multi-layer model. These ROS values were assigned to participants' postal codes at birth. Cox proportional hazards regression models, adjusted for confounders, were then used to estimate hazard ratios (HR) with 95% confidence intervals (CI) per unit increase in interquartile range (IQR). RESULTS: After adjusting for confounders, iron (Fe) and copper (Cu) were not significantly associated with the risk of asthma, allergic rhinitis, nor eczema. However, ROS, a measure of the combined impacts of Fe and Cu in PM2.5, was associated with an increased risk of asthma (HR = 1.11, 95% CI: 1.02-1.21, p < 0.02) per IQR. There were no statistically significant associations of ROS with allergic rhinitis (HR = 0.96, 95% CI: 0.88-1.04, p = 0.35) and eczema (HR = 1.03, 95% CI: 0.98-1.09, p = 0.24). CONCLUSION: These findings showed that ROS exposure in early life significantly increased the childhood risk of asthma, but not allergic rhinitis and eczema.

Pediatric Clinical Classification System for use in Canadian inpatient settings.

BACKGROUND: A classification system that categorizes International Statistical Classification of Diseases and Related Health Problems, Tenth Revision (ICD-10) diagnosis codes into clinically meaningful categories is important for pediatric clinical and health services research using administrative data. While a Pediatric Clinical Classification System (PECCS) is available for the United States ICD-10 system (i.e, ICD-10-CM), differences in the ICD-10 system between countries limits PECCS use in Canada. OBJECTIVE: To translate PECCS from ICD-10-CM to ICD-10-CA for use in Canada (PECCS-CA), and examine the utility of PECCS-CA in administrative data of pediatric hospital encounters in Ontario, Canada. METHODS: PECCS was translated by mapping each ICD-10-CA code to its corresponding ICD-10-CM code, based on code description and alphanumeric code, using automated functions in Microsoft Excel. All unmatched ICD-10-CA codes were manually matched to an ICD-10-CM code. The ICD-10-CA codes were mapped to a PECCS category based on the placement of the corresponding ICD-10-CM code. Finally, in this cross-sectional study, the utility of PECCS-CA was examined in pediatric hospital encounters in children <18 years of age with an inpatient or same day surgery encounter, between April 1, 2014 to March 31, 2019 in Ontario. RESULTS: In total, 16,992 ICD-10-CA diagnosis codes were mapped to 781 mutually exclusive condition categories that included pediatric specific conditions and treatments in PECCS-CA. From the 781 categories, 777 (99.5%) were derived from the original PECCS, 3 (0.4%) from merging the original PECCS categories, and 1 (0.1%) was newly developed. The PECCS-CA was applied to health administrative data of 911,732 hospital encounters in children. The most prevalent condition in children was low birth weight (n = 54,100 encounters). CONCLUSION: The PECCS-CA is an open-source classification system which maps ICD-10-CA codes into 781 clinically important pediatric categories. The PECCS-CA can be used for pediatric health services and outcomes research in Canada.

Cannabis use and risks of respiratory and all-cause morbidity and mortality: a population-based, data-linkage, cohort study.

INTRODUCTION: Although cannabis is frequently used worldwide, its impact on respiratory health is characterised by controversy. OBJECTIVE: To evaluate the association between cannabis use and respiratory-related emergency room (ER) visits and hospitalisations. METHODS: A retrospective, population-based, cohort study was carried out, linking health survey and health administrative data for residents of Ontario, Canada, aged 12-65 years, between January 2009 and December 2015. Individuals self-reporting cannabis use within the past year were matched to control individuals (people who reported never using cannabis, or used cannabis only once, and more than 12 months ago) in upwards of a 1:3 ratio on 31 different variables, using propensity score matching methods. Respiratory-related and all-cause ER visits or hospitalisations, and all-cause mortality, were evaluated up to 12 months following the index date. RESULTS: We identified 35 114 individuals who had either used cannabis in the past year or were controls, of whom 6425 (18.3%) used cannabis in the past year. From this group, 4807 (74.8%) were propensity-score matched to 10 395 control individuals. In the propensity score matched cohort, there was no significant difference in odds of respiratory-related ER visit or hospitalisation between cannabis users and the control group (OR 0.91, 95% CI 0.77 to 1.09). Compared with control individuals, cannabis users had significantly increased odds of all-cause ER visit or hospitalisation (OR 1.22, 95% CI 1.13 to 1.31) and there was no significant difference with respect to all-cause mortality (OR 0.99, 95% CI 0.49 to 2.02). CONCLUSIONS: Although no significant association was observed between cannabis use and respiratory-related ER visits or hospitalisations, the risk of an equally important morbidity outcome, all-cause ER visit or hospitalisation, was significantly greater among cannabis users than among control individuals. Therefore, cannabis use is associated with increased risk for serious adverse health events and its recreational consumption is not benign.

Is overreliance on short-acting ß2-agonists associated with health risks in the older asthma population?

Recent Global Initiative for Asthma (GINA) recommendations reduce the role of short-acting ß2-agonist (SABA) premised on the associated exacerbation risk. The widely accepted SABA risk profile is based on limited data described 30 years ago. This GINA paradigm shift demands an examination of SABA risks in a modern therapeutic era. Recent studies confirm that SABA overuse is common and associated with adverse outcomes. This study aimed to determine associations between SABA use, all-cause mortality and asthma exacerbations in an older North American asthma population. In this population-based cohort study, individuals with prevalent asthma (2006-2015) aged ≥65 years, eligible for provincial drug coverage, were included. Annual SABA canisters filled (0, 1-2, 3-5, ≥6) was the primary exposure. Hazard ratios (HRs) with 95% CIs were estimated using Cox proportional hazard regression, adjusted for confounders. There were 59 533 asthma individuals; 14% overused SABA (≥3 canisters annually). Compared to those who used <3 canisters, the adjusted HRs of death for those who used 3-5 and ≥6 canisters were 1.11 (95% CI: 1.02-1.22, p=0.0157) and 1.56 (95% CI: 1.41-1.71, p<0.0001), respectively. Severe asthma exacerbation rates for ≥3 and <3 canisters/year were 7.5% and 2.1%, respectively. The adjusted HRs of severe asthma exacerbations were 1.59 (95% CI: 1.40-1.82, p<0.0001) and 2.26 (95% CI: 1.96-2.60, p<0.0001) in those who used 3-5 and ≥6 SABA canisters per year, respectively. In Canada, 1 in 7 individuals with asthma overused SABA associated with increased risks of severe asthma exacerbations and death. The adverse impacts of SABA overuse continue 30 years after early publications.

Prevalence, Cost, and Variation in Cost of Pediatric Hospitalizations in Ontario, Canada.

Importance: Identifying conditions that could be prioritized for research based on health care system burden is important for developing a research agenda for the care of hospitalized children. However, existing prioritization studies are decades old or do not include data from both pediatric and general hospitals. Objective: To assess the prevalence, cost, and variation in cost of pediatric hospitalizations at all general and pediatric hospitals in Ontario, Canada, with the aim of identifying conditions that could be prioritized for future research. Design, Setting, and Participants: This population-based cross-sectional study used health administrative data from 165 general and pediatric hospitals in Ontario, Canada. Children younger than 18 years with an inpatient hospital encounter between April 1, 2014, and March 31, 2019, were included. Main Outcomes and Measures: Condition-specific prevalence, cost of pediatric hospitalizations, and condition-specific variation in cost per inpatient encounter across hospitals. Variation in cost was evaluated using (1) intraclass correlation coefficient (ICC) and (2) number of outlier hospitals. Costs were adjusted for inflation to 2018 US dollars. Results: Overall, 627 314 inpatient hospital encounters (44.8% among children younger than 30 days and 53.0% among boys) at 165 hospitals (157 general and 8 pediatric) costing $3.3 billion were identified. A total of 408 003 hospitalizations (65.0%) and $1.4 billion (43.8%) in total costs occurred at general hospitals. Among the 50 most prevalent and 50 most costly conditions (of 68 total conditions), the top 10 highest-cost conditions accounted for 55.5% of all costs and 48.6% of all encounters. The conditions with highest prevalence and cost included low birth weight (86.2 per 1000 encounters; $676.3 million), preterm newborn (38.0 per 1000 encounters; $137.4 million), major depressive disorder (20.7 per 1000 encounters; $78.3 million), pneumonia (27.3 per 1000 encounters; $71.6 million), other perinatal conditions (68.0 per 1000 encounters; $65.8 million), bronchiolitis (25.4 per 1000 encounters; $54.6 million), and neonatal hyperbilirubinemia (47.9 per 1000 encounters; $46.7 million). The highest variation in cost per encounter among the most costly medical conditions was observed for 2 mental health conditions (other mental health disorders [ICC, 0.28] and anxiety disorders [ICC, 0.19]) and 3 newborn conditions (intrauterine hypoxia and birth asphyxia [ICC, 0.27], other perinatal conditions [ICC, 0.17], and surfactant deficiency disorder [ICC, 0.17]). Conclusions and Relevance: This population-based cross-sectional study of hospitalized children identified several newborn and mental health conditions as having the highest prevalence, cost, and variation in cost across hospitals. Findings of this study can be used to develop a research agenda for the care of hospitalized children that includes general hospitals and to ultimately build a more substantial evidence base and improve patient outcomes.

Did Emergency Department Visits in Infants and Young Children Increase in the Last Decade?: An Ontario, Canada Study.

OBJECTIVES: The aims of the study were to measure overall trends and to identify leading causes for pediatric emergency department (ED) visits among children aged 0 to 4 years. METHODS: We conducted an 11-year population-based open cohort study using health administrative data from 2008 to 2018 in Ontario, Canada. All ED visits were extracted from the National Ambulatory Care Reporting System, along with the most responsible cause of each visit. Annual ED visit rates were calculated per 100 children in each year. Overall and disease-specific rates for all children were calculated and then stratified by sex and age groups. Relative percentage change in rates between 2008 and 2018 were calculated and compared using standardized differences (SDIFs). Statistical significance of time trends was tested using Poisson regression. RESULTS: This study included an average of 911,566 children from 2008 to 2018. All-cause ED visit rates increased by 28.2% from 2008 to 2018 (43.24-55.42 per 100, SDIF >0.1). Respiratory diseases were consistently the top cause of ED visits, and contributed to 1 in 3 ED visits in 2018. These respiratory conditions include asthma, asthma-related diseases (bronchiolitis, bronchitis, influenza, and pneumonia), and other respiratory diseases. Respiratory ED visit rates increased by 32.8% from 2008 to 2018 (11.51-15.28 per 100, SDIF <0.1), driven by a 46.4% (14.58-21.35 per 100, SDIF >0.1) increase among children younger than 1 year. There was a 78.0% increase in ED visits for bronchiolitis in infants (1.45-2.58 per 100, SDIF <0.1). CONCLUSIONS: Respiratory diseases like bronchiolitis among infants were the consistent leading cause for ED visits. All-cause ED visit rates among young children increased by 28.17% from 2008 to 2018.

Bridging Pediatric and Adult Rehabilitation Services for Young Adults With Childhood-Onset Disabilities: Evaluation of the LIFEspan Model of Transitional Care.

Background: LIFEspan ("Living Independently and Fully Engaged") is a linked transition service model for youth and young adults with childhood-onset disabilities offered via an inter-agency partnership between two rehabilitation hospitals (one pediatric and one adult) in Toronto, Canada. Objective: The objective was to evaluate healthcare outcomes (continuity of care and healthcare utilization) for clients enrolled in LIFEspan. Methods: A prospective, longitudinal, observational mixed-method study design was used. The intervention group comprised youth with Acquired Brain Injury (ABI) and Cerebral Palsy (CP) enrolled in LIFEspan. A prospective comparison group comprised youth with Spina Bifida (SB) who received standard care. A retrospective comparison group comprised historical, disability-matched clients (with ABI and CP) discharged prior to model introduction. Medical charts were audited to determine continuity of care, i.e., whether study participants had at least one visit to an adult provider within 1 year post-discharge from the pediatric hospital. Secondary outcomes related to healthcare utilization were obtained from population-based, health service administrative datasets. Data were collected over a 3-year period: 2 years pre and 1 year post pediatric discharge. Rates were estimated per person-year. Fisher's Exact Test was used to examine differences between groups on the primary outcome, while repeated measures GEE Poisson regression was used to estimate rate ratios (post vs. pre) with 95% confidence intervals for the secondary outcomes. Results: Prospective enrolment comprised 30 ABI, 48 CP, and 21 SB participants. Retrospective enrolment comprised 15 ABI and 18 CP participants. LIFEspan participants demonstrated significantly greater continuity of care (45% had engagement with adult services in the year following discharge at 18 years), compared to the prospective SB group (14%). Healthcare utilization data were inconsistent with no significant changes in frequency of physician office visits, emergency department visits, or hospitalizations for clients enrolled in LIFEspan in the year following discharge, compared to the 2 years prior to discharge. Conclusion: Introduction of the LIFEspan model increased continuity of care, with successful transfer from pediatric to adult services for clients enrolled. Data on longer-term follow-up are recommended for greater understanding of the degree of adult engagement and influence of LIFEspan on healthcare utilization following transfer.

Effect of smoke-free legislation on respiratory health services use in children with asthma: a population-based open cohort study in Ontario, Canada.

OBJECTIVE: This study will add to existing literature by examining the impact of smoke-free legislation in outdoor areas among children with asthma. We aimed to examine the effect of the 2015 Smoke-Free Ontario Act (SFOA) amendment, which prohibited smoking on patios, playgrounds and sports fields, on health services use (HSU) rates in children with asthma. METHODS: We conducted a population-based open cohort study using health administrative data from the province of Ontario, Canada. Each year, all Ontario residents aged 0-18 years with physician diagnosed asthma were included in the study. Annual rates of HSU (emergency department (ED) visits, hospitalisations and physician office visits) for asthma and asthma-related conditions (eg, bronchitis, allergic rhinitis, influenza and pneumonia) were calculated. Interrupted time-series analysis, accounting for seasonality, was used to estimate changes in HSU following the 2015 SFOA. RESULTS: The study population ranged from 618 957 individuals in 2010 to 498 812 in 2018. An estimated average increase in ED visits for asthma in infants aged 0-1 years of 0.42 per 100 individuals (95% CI: 0.09 to 0.75) and a 57% relative increase corresponding to the 2015 SFOA was observed. A significant decrease in ED visits for asthma-related conditions of 0.19 per 100 individuals (95% CI: -0.37 to -0.01) and a 22% relative decrease corresponding to the 2015 SFOA was observed. CONCLUSION: Based on the observed positive effect of restricting smoking on patios, playgrounds and sports fields on respiratory morbidity in children with asthma, other jurisdictions globally should consider implementing similar smoke-free policies.

Does exposure to air pollution increase the risk of acute care in young children with asthma? An Ontario, Canada study.

Owing to their greater outdoor activity and ongoing lung development, children are particularly vulnerable to the harmful effects of exposure to fine particulate matter (PM2.5). However, the effects of PM2.5 components are poorly understood. This study aimed to use a longitudinal birth cohort of children with physician-diagnosed incident asthma to investigate the effect of PM2.5 components at birth on morbidity measured by health services utilization. Of 1277 Toronto Child Health Evaluation Questionnaire (T-CHEQ) participants, the study population included 362 children diagnosed with asthma who were followed for a mean of 13 years from birth until March 31, 2016, or loss-to-follow-up. Concentrations of PM2.5 and its components were assigned based on participants' postal codes at birth. Study outcomes included counts of asthma, asthma-related, and all-cause health services use. Poisson regression in single-, two-, and multi-pollutant models was used to estimate rate ratios (RR) per interquartile range (IQR) increase of exposures. Covariates were included in all models to further adjust for potential confounding. The adjusted RR for sulfate (SO4) and all-cause hospitalizations was statistically significant with RR = 2.23 (95% confidence interval [CI]: 1.25-3.96) in a multi-pollutant model with nitrogen dioxide (NO2) and ozone (O3). In multi-pollutant models with oxidants, the adjusted RRs for SO4 of all-cause hospitalizations and emergency department (ED) visits were also statistically significant with RR = 2.31 (95% CI: 1.32-4.03) and RR = 1.39 (95% CI: 1.02-1.90), respectively. While unadjusted single-pollutant RRs for asthma-specific and asthma-related health services use with the SO4 component of PM2.5 were above one, none were statistically significant. This study found significant associations with exposure to SO4 in PM2.5 and all-cause acute care, chiefly for hospitalizations, in children with asthma.

Antibiotic use in children and youths with asthma: a population-based case-control study.

RATIONALE: Antibiotics are among the most common medications dispensed to children and youths. The objective of this study was to characterise and compare antibiotic use patterns between children and youths with and without asthma. METHODS: We conducted a population-based nested case-control study using health administrative data from Ontario, Canada, in 2018. All Ontario residents aged 5-24 years with asthma were included as cases. Cases were matched to controls with a 1:1 ratio based on age (within 0.5 year), sex and location of residence. Multivariable conditional logistic regression was used to obtain an odds ratio and 95% confidence interval for having filled at least one antibiotic prescription, adjusted for socioeconomic status, rurality, and presence of common infections, allergic conditions and complex chronic conditions. RESULTS: The study population included 1 174 424 Ontario children and youths aged 5-24 years. 31% of individuals with asthma and 23% of individuals without asthma filled at least one antibiotic prescription. The odds of having filled at least one antibiotic prescription were 34% higher among individuals with asthma compared to those without asthma (OR 1.34, 95% CI 1.32-1.35). In the stratified analysis, the odds ratios were highest in the youngest group of children studied, aged 5-9 years (OR 1.45, 95% CI 1.41-1.48), and in females (OR 1.36, 95% CI 1.34-1.38). CONCLUSION: Asthma is significantly associated with increased antibiotic use in children and youths. This association is the strongest in younger children and in females.

Correlation of ambient temperature and COVID-19 incidence in Canada.

The SARS-CoV-2 is a novel coronavirus identified as the cause of COVID-19 and, as the pandemic evolves, many have made parallels to previous epidemics such as SARS-CoV (the cause of an outbreak of severe acute respiratory syndrome [SARS]) in 2003. Many have speculated that, like SARS, the activity of SARS-CoV-2 will subside when the climate becomes warmer. We sought to determine the relationship between ambient temperature and COVID-19 incidence in Canada. We analyzed over 77,700 COVID-19 cases from four Canadian provinces (Alberta, British Columbia, Ontario, and Quebec) from January to May 2020. After adjusting for precipitation, wind gust speed, and province in multiple linear regression models, we found a positive, but not statistically significant, association between cumulative incidence and ambient temperature (14.2 per 100,000 people; 95%CI: -0.60-29.0). We also did not find a statistically significant association between total cases or effective reproductive number of COVID-19 and ambient temperature. Our findings do not support the hypothesis that higher temperatures will reduce transmission of COVID-19 and warns the public not to lose vigilance and to continue practicing safety measures such as hand washing, social distancing, and use of facial masks despite the warming climates.

UV, ozone, and COVID-19 transmission in Ontario, Canada using generalised linear models.

BACKGROUND: Quantifying the impact of environmental factors on COVID-19 transmission is crucial in preventing more cases. Ultraviolet (UV) radiation and ozone (O3) have reported antimicrobial properties but few studies have examined associations with community infectivity of COVID-19. Research suggests UV light can be preventative while the effect of O3 is contested. We sought to determine the relationship between UV, O3, and COVID-19 incidence in Ontario, Canada. METHODS: In our time series analyses, we calculated daily incidence rates and reproductive number (Rt) from 34,975 cases between January and June 2020 across 34 Ontario Public Health Units. We used generalised linear models, adjusting for potential confounders, to calculate point estimates (PE) and 95% confidence intervals (CI) for UV and O3. Analyses were further stratified by age groups and outbreaks at institutions versus community. RESULTS: We found that 1-week averaged UV was significantly associated with a 13% decrease (95% CI: 0.80-0.96) in overall COVID-19 Rt, per unit increase. A negative association with UV was also significant among community outbreaks (PE: 0.88, 95% CI: 0.81-0.96) but not institutional outbreaks (PE: 0.94, 95% CI: 0.85-1.03). A positive association of O3 with COVID-19 incidence is strongly suggested among institutional outbreak cases (PE: 1.06, 95% CI: 1.00-1.13). CONCLUSION: Our study found evidence to support the hypothesis that higher UV reduced transmission of COVID-19 and some evidence that ground-level O3 positively influenced COVID-19 transmission. Setting of infection should be strongly considered as a factor in future research. UV and O3 may explain some of COVID-19's seasonal behaviour.

Does an mHealth system reduce health service use for asthma?

BACKGROUND: Breathe is a mobile health (mHealth) application developed for the self-management of asthma in adults. There is evidence to suggest that mHealth interventions can be used for asthma control; however, their effects on the use of health services remain poorly understood. We sought to determine whether Breathe reduces health services use amongst asthma patients who used the app compared to controls who did not. METHODS: The impact of Breathe on health services use was estimated using a quasi-experimental approach. Two groups of subjects who had participated in a previous randomised clinical trial were included: an intervention group of asthma patients who used the app for 12 months, and a group of controls who did not use the app but received equivalent quality asthma care. A third, external control group of asthma patients were matched to the intervention participants. Generalised linear mixed models were used to determine relative changes in rates of asthma hospitalisations, emergency department (ED) visits, outpatient physician visits and completion of pulmonary function tests (PFTs) over time. RESULTS: A total of 677 individuals with asthma were included in the study: 132 in the intervention group, and 149 and 396 in the internal and external control groups, respectively. There were no statistically significant differences in the change of asthma hospitalisations, ED visits, physician office visits or completion of PFTs between the intervention group and either control group. CONCLUSIONS: Use of the Breathe app is not associated with changes in health services use in adults with asthma.

Early life exposure to air pollution and incidence of childhood asthma, allergic rhinitis and eczema.

RATIONALE: There is growing evidence that air pollution may contribute to the development of childhood asthma and other allergic diseases. In this follow-up of the Toronto Child Health Evaluation Questionnaire (T-CHEQ) study, we examined associations between early life exposures to air pollution and incidence of asthma, allergic rhinitis and eczema from birth through adolescence. METHODS: 1286 T-CHEQ participants were followed from birth until outcome (March 31, 2016) or loss to follow-up, with a mean of 17 years of follow-up. Concentrations of nitrogen dioxide (NO2), ozone (O3) and particulate matter with a 50% cut-off aerodynamic diameter of 2.5 µm (PM2.5) from January 1, 1999 to December 31, 2012 were assigned to participants based on their postal codes at birth using ground observations, chemical/meteorological models, remote sensing and land-use regression models. Study outcomes included incidence of physician-diagnosed asthma, allergic rhinitis and eczema. Cox proportional hazard regression models were used to estimate hazard ratios per interquartile range of exposures and outcomes, adjusting for potential confounders. RESULTS: Hazard ratios of 1.17 (95% CI 1.05-1.31) for asthma and 1.07 (95% CI 0.99-1.15) for eczema were observed for total oxidants (O3 and NO2) at birth. No significant increase in risk was found for PM2.5. CONCLUSIONS: Exposures to oxidant air pollutants (O3 and NO2) but not PM2.5 were associated with an increased risk of incident asthma and eczema in children. This suggests that improving air quality may contribute to the prevention of asthma and other allergic disease in childhood and adolescence.