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.

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.

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.

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 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.

Effect of asthma exacerbation during pregnancy in women with asthma: a population-based cohort study.

The association between asthma exacerbation during pregnancy and adverse maternal and child health outcomes have not been investigated appropriately. Our objective was to determine the short- and long-term intergenerational effect of asthma exacerbation in pregnant women with asthma.A population cohort study was conducted using data from the Ontario asthma surveillance system and population-level health administrative data. Asthma exacerbation in pregnant women with asthma was defined as at least one of the following criteria: at least five physician visits, or one emergency department visit or one hospital admission for asthma during pregnancy. Pregnancy complications, adverse perinatal outcomes and early childhood respiratory disorders were identified using International Classification of Disease codes (9th and 10th revisions).The cohort consisted of 103 424 singleton pregnancies in women with asthma. Asthma exacerbation in pregnant women with asthma was associated with higher odds of pre-eclampsia (OR 1.30, 95% CI 1.12-1.51) and pregnancy-induced hypertension (OR 1.17, 95% CI 1.02-1.33); babies had higher odds of low birthweight (OR 1.14, 95% CI 1.00-1.31), preterm birth (OR 1.14, 95% CI 1.01-1.29) and congenital malformations (OR 1.21, 95% CI 1.05-1.39). Children born to women with asthma exacerbation during pregnancy had elevated risk of asthma (OR 1.23, 95% CI 1.13-1.33) and pneumonia (OR 1.12, 95% CI 1.03-1.22) during the first 5 years of life.Asthma exacerbation during pregnancy in women with asthma showed increased risk of pregnancy complications, adverse perinatal outcomes and early childhood respiratory disorders in their children, indicating that appropriate asthma management may reduce the risk of adverse health outcomes.

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.

Montelukast and Neuropsychiatric Events in Children with Asthma: A Nested Case-Control Study.

OBJECTIVE: To examine the association between montelukast prescription and neuropsychiatric events in children with asthma. STUDY DESIGN: A matched, nested case-control design was used to identify cases and controls from a cohort of children aged 5-18 years with physician-diagnosed asthma from 2004 to 2015, in Ontario, Canada, prescribed an asthma maintenance medication. Cases were children with a hospitalization or emergency department visit for a neuropsychiatric event. Cases were matched to up to 4 controls on birth year, year of asthma diagnosis, and sex. The exposures were dispensed prescriptions for montelukast (yes/no) and number of dispensed montelukast prescriptions in the year before the index date. Conditional logistic regression was used to measure the unadjusted OR and aOR and 95% CIs for montelukast prescription and neuropsychiatric events. Covariates in the adjusted model included sociodemographic factors and measures of asthma severity. RESULTS: In total, 898 cases with a neuropsychiatric event and 3497 matched controls were included. Children who experienced a new-onset neuropsychiatric event had nearly 2 times the odds of having been prescribed montelukast, compared with controls (OR 1.91, 95% CI 1.15-3.18; P = .01). Most cases presented for anxiety (48.6%) and/or sleep disturbance (26.1%). CONCLUSIONS: Children with asthma who experienced a new-onset neuropsychiatric event had nearly twice the odds of having been prescribed montelukast in the year before their event. Clinicians should be aware of the association between montelukast and neuropsychiatric events in children with asthma, to inform prescribing practices and clinical follow-up.

Asthma health services utilisation before, during and after pregnancy: a population-based cohort study.

During pregnancy, females with asthma may be at higher risk of exacerbation. The objective of this study was to determine whether females with asthma in Ontario, Canada have increased health services utilisation (HSU) during pregnancy.Rates of asthma-specific, asthma-related and non-pregnancy-related HSU were calculated in a population-based cohort of pregnant females with asthma. Poisson regression with repeated measures was used to determine adjusted rate ratios and 95% confidence intervals of HSU during and 1 year after pregnancy, compared to the year before pregnancy.The cohort consisted of 103 976 pregnant females with asthma. Compared to the year prior to pregnancy, hospitalisation rates per 100 person-months during pregnancy increased 30% for asthma (from 0.016 to 0.020), 24% for asthma-related conditions (from 0.012 to 0.015) and decreased 37% for non-pregnancy-related conditions (from 0.24 to 0.15). Emergency department visits for asthma and asthma-related conditions did not increase significantly during pregnancy. During pregnancy, physician office visits decreased 19% for asthma (from 2.20 to 1.79), 10% for asthma-related conditions (from 9.44 to 8.47) and increased 74% for non-pregnancy-related conditions (from 56.4 to 98.2).Hospitalisations for asthma and asthma-related conditions increased during pregnancy, demonstrating that the overall increase in non-pregnancy-related physician office visits may not meet the primary care needs of pregnant females with asthma.

Progression from Asthma to Chronic Obstructive Pulmonary Disease. Is Air Pollution a Risk Factor?

RATIONALE: Individuals with asthma-chronic obstructive pulmonary disease (COPD) overlap syndrome (ACOS), have more rapid decline in lung function, more frequent exacerbations, and poorer quality of life than those with asthma or COPD alone. Air pollution exposure is a known risk factor for asthma and COPD; however, its role in ACOS is not as well understood. OBJECTIVES: To determine if individuals with asthma exposed to higher levels of air pollution have an increased risk of ACOS. METHODS: Individuals who resided in Ontario, Canada, aged 18 years or older in 1996 with incident asthma between 1996 and 2009 who participated in the Canadian Community Health Survey were identified and followed until 2014 to determine the development of ACOS. Data on exposures to fine particulate matter (PM2.5) and ozone (O3) were obtained from fixed monitoring sites. Associations between air pollutants and ACOS were evaluated using Cox regression models. MEASUREMENTS AND MAIN RESULTS: Of the 6,040 adults with incident asthma who completed the Canadian Community Health Survey, 630 were identified as ACOS cases. Compared with those without ACOS, the ACOS population had later onset of asthma, higher proportion of mortality, and more frequent emergency department visits before COPD diagnosis. The adjusted hazard ratios of ACOS and cumulative exposures to PM2.5 (per 10 µg/m(3)) and O3 (per 10 ppb) were 2.78 (95% confidence interval, 1.62-4.78) and 1.31 (95% confidence interval, 0.71-2.39), respectively. CONCLUSIONS: Individuals exposed to higher levels of air pollution had nearly threefold greater odds of developing ACOS. Minimizing exposure to high levels of air pollution may decrease the risk of ACOS.

Frequency of health service use in the year prior to asthma death.

OBJECTIVE: High frequency health service use (HSU) is associated with poorly controlled asthma, and is a recognized risk factor for near-fatal or fatal asthma. The objective of this study was to describe the frequency of HSU in the year prior to asthma death. METHODS: Individuals aged 0-99 years who died from asthma from April 1996 to December 2011 in Ontario, Canada were identified as cases. Cases were matched to 4-5 live asthma controls by age, sex, rural/urban residence, socioeconomic status, duration of asthma and a co-diagnosis of COPD. HSU records in the year prior to death [hospitalization, emergency department (ED) and outpatient visits] were assembled. The association of prior HSU and asthma death was measured by conditional logistic regression models. RESULTS: From 1996 to 2011, 1503 individuals died from asthma. While the majority of cases did not have increased HSU as defined in the study, compared to matched live asthma controls, the cases were 8-fold more likely to have been hospitalized two or more times (OR = 7.60; 95% CI: 4.90, 11.77), 13-fold more likely to have had three or more ED visits (OR = 13.28; 95% CI: 7.55, 23.34) and 4-fold more likely to have had five or more physician visits for asthma (OR = 4.41; 95% CI: 3.58, 5.42). CONCLUSIONS: Frequency of HSU in the year prior was substantially higher in those died from asthma. Specifically, more than one asthma hospital admission, three ED visits or five physician visits increased the asthma mortality risk substantially and exponentially.

Quality of asthma care under different primary care models in Canada: a population-based study.

BACKGROUND: Previous research has shown variations in quality of care and patient outcomes under different primary care models. The objective of this study was to use previously validated, evidence-based performance indicators to measure quality of asthma care over time and to compare quality of care between different primary care models. METHODS: Data were obtained for years 2006 to 2010 from the Ontario Asthma Surveillance Information System, which uses health administrative databases to track individuals with asthma living in the province of Ontario, Canada. Individuals with asthma (n=1,813,922) were divided into groups based on the practice model of their primary care provider (i.e., fee-for-service, blended fee-for-service, blended capitation). Quality of asthma care was measured using six validated, evidence-based asthma care performance indicators. RESULTS: All of the asthma performance indicators improved over time within each of the primary care models. Compared to the traditional fee-for-service model, the blended fee-for-service and blended capitation models had higher use of spirometry for asthma diagnosis and monitoring, higher rates of inhaled corticosteroid prescription, and lower outpatient claims. Emergency department visits were lowest in the blended fee-for-service group. CONCLUSIONS: Quality of asthma care improved over time within each of the primary care models. However, the amount by which they improved differed between the models. The newer primary care models (i.e., blended fee-for-service, blended capitation) appear to provide better quality of asthma care compared to the traditional fee-for-service model.

Uptake and cardiac events of COVID-19 vaccinations among Canadian youth and young adults.

Few studies have examined population-level data of the COVID-19 original and bivalent vaccine on its uptake and potential side effects. We used population-based health administrative data from Jan 2021-Feb 2023 to identify Ontario residents aged 12-35 years old to calculate their rates of COVID-19 vaccine uptake and vaccine-related cardiac events (myocarditis and pericarditis). Multivariable Cox, logistic, and negative binomial regression analyses were used to adjust for covariates. Hazard ratios (HR) were reported with 95% confidence intervals (CI). The study population included 5,012,721 individuals. Comparing to the general population, those with chronic diseases were associated with 13-37% higher rates of vaccine uptake and 1.39-2.27 times higher odds of receiving booster doses. Overall, post-vaccination cardiac event incidence rates ranged from 3-12 per 100,000 persons. Compared to the general population, the incidence rate of cardiac events among those with asthma and allergic diseases was significantly higher, 3.7 events per 100,000 persons. Compared to the general population, those with asthma and/or allergic diseases had significantly higher associated likelihoods of a cardiac event (HR = 1.31, 95% CI: 1.08-1.57). Females, adults, and those with prior COVID-19 infections had decreased odds of cardiac events after 2nd vaccine doses. No significant differences in post-vaccine cardiac events were detected between original and bivalent doses. This Canadian population-based study reported substantially higher rates of vaccine uptake and a very rare incidence of temporally associated post-vaccination cardiac events. While substantially smaller than the benefits of vaccination, our results indicated a continued small risk of cardiac side effects from bivalent COVID-19 vaccines in individuals with comorbidities.

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.

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.

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.

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.

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.