Suicidality among sexual minority and transgender adolescents: a nationally representative population-based study of youth in Canada

Background:Very little research has described risk of suicidal ideation and suicide attempt among transgender youth using high-quality, nationally representative data. We aimed to assess risk of suicidality among transgender and sexual minority adolescents in Canada.Methods:We analyzed a subsample of adolescents aged 15–17 years from the 2019 Canadian Health Survey on Children and Youth, a nationally representative, cross-sectional survey. We defined participants’ transgender identity (self-reported gender different from sex assigned at birth) and sexual minority status (self-reported attraction to people of the same gender) as exposures, and their self-reported previous-year suicidal ideation and lifetime suicide attempt as outcomes.Results:We included 6800 adolescents aged 15–17 years, including 1130 (16.5%) who indicated some degree of same-gender attraction, 265 (4.3%) who were unsure of their attraction and 50 (0.6%) who reported a transgender identity. Compared with cisgender, heterosexual adolescents, transgender adolescents showed 5 times the risk of suicidal ideation (95% confidence interval [CI] 3.63 to 6.75; 58% v. 10%) and 7.6 times the risk of suicide attempt (95% CI 4.76 to 12.10; 40% v. 5%). Among cisgender adolescents, girls attracted to girls had 3.6 times the risk of previous-year suicidal ideation (95% CI 2.59 to 5.08) and 3.3 times the risk of having ever attempted suicide (95% CI 1.81 to 6.06), compared with their heterosexual peers. Adolescents attracted to multiple genders had 2.5 times the risk of suicidal ideation (95% CI 2.12 to 2.98) and 2.8 times the risk of suicide attempt (95% CI 2.18 to 3.68). Youth questioning their sexual orientation had twice the risk of having attempted suicide in their lifetime (95% CI 1.23 to 3.36).Interpretation:We observed that transgender and sexual minority adolescents were at increased risk of suicidal ideation and attempt compared with their cisgender and heterosexual peers. These findings highlight the need for inclusive prevention approaches to address suicidality among Canada’s diverse youth population.

Suicide is the second leading cause of death among adolescents and young adults aged 15–24 years in Canada.^1,2 Suicidal ideation and suicide attempt are common among adolescents³ and are risk factors for death by suicide.⁴ Sexual minority youth (i.e., youth who are attracted to the same gender or multiple genders, or who identify as lesbian, gay, bisexual or queer)⁵ are known to be at increased risk of poor mental health,^6–8 including suicidal ideation and attempt.^5–10 Over the previous 2 decades, stigma around identifying as a sexual minority has reduced;⁷ however, the risk of poor mental health and of suicidality remains high among sexual minority youth.^7,11 This population is still more likely to experience bullying and peer victimization,^9,12,13 which is associated with suicidality among sexual minority adolescents.⁵Transgender youth are those whose gender identity does not match their sex assigned at birth.¹⁴ Among other terms, gender-nonconforming, nonbinary, genderqueer and genderfluid are used to describe the gender identity of a subset of young people who identify outside the gender binary (i.e., as neither male nor female) or who experience fluidity between genders.⁹ Suicidality among transgender and gender-nonconforming adolescents is not as well studied. In a Canadian survey of transgender and gender-nonconforming youth aged 14–25 years, 64% of participants reported that they had seriously considered suicide in the previous 12 months.¹⁵ Transgender and gender-nonconforming youth seem to have a higher probability of many risk factors for suicidality, including peer victimization,^8,16 family dysfunction^7,17 and barriers to accessing mental health care.¹⁸ However, the epidemiology of suicidality among transgender and gender-nonconforming youth remains understudied in population-based samples; most research on the mental health of transgender youth comes from small community samples of help-seeking youth or targeted surveys of transgender adolescents.^5,19,20 Two population-based studies from California²¹ and New Zealand²² suggested that transgender youth are at increased risk of suicidal ideation and suicide attempt. However, only the New Zealand study²² used the gold-standard measure of gender identity, contrasting adolescents’ sex assigned at birth with their self-identified gender.²³Further epidemiological research employing large, representative samples and adequate measures of gender identity is needed to understand the burden of suicidality among lesbian, gay, bisexual, transgender and queer youth. We sought to build on existing evidence to assess risk of suicidal ideation and attempt among transgender and sexual minority adolescents in Canada, as compared with their cisgender and heterosexual peers, as well as to explore the relation between suicidality and experience of bullying.     

Diversity among health care leaders in Canada: a cross-sectional study of perceived gender and race

Background:Diverse health care leadership teams may improve health care experiences and outcomes for patients. We sought to explore the race and gender of hospital and health ministry executives in Canada and compare their diversity with that of the populations they serve.Methods:This cross-sectional study included leaders of Canada’s largest hospitals and all provincial and territorial health ministries. We included individuals listed on institutional websites as part of the leadership team if a name and photo were available. Six reviewers coded and analyzed the perceived race and gender of leaders, in duplicate. We compared the proportion of racialized health care leaders with the race demographics of the general population from the 2016 Canadian Census.Results:We included 3056 leaders from 135 institutions, with reviewer concordance on gender for 3022 leaders and on race for 2946 leaders. Reviewers perceived 37 (47.4%) of 78 health ministry leaders as women, and fewer than 5 (< 7%) of 80 as racialized. In Alberta, Saskatchewan, Prince Edward Island and Nova Scotia, provinces with a centralized hospital executive team, reviewers coded 36 (50.0%) of 72 leaders as women and 5 (7.1%) of 70 as racialized. In British Columbia, New Brunswick and Newfoundland and Labrador, provinces with hospital leadership by region, reviewers perceived 120 (56.1%) of 214 leaders as women and 24 (11.5%) of 209 as racialized. In Manitoba, Ontario and Quebec, where leadership teams exist at each hospital, reviewers perceived 1326 (49.9%) of 2658 leaders as women and 243 (9.2%) of 2633 as racialized. We calculated the representation gap between racialized executives and the racialized population as 14.5% for British Columbia, 27.5% for Manitoba, 20.7% for Ontario, 12.4% for Quebec, 7.6% for New Brunswick, 7.3% for Prince Edward Island and 11.6% for Newfoundland and Labrador.Interpretation:In a study of more than 3000 health care leaders in Canada, gender parity was present, but racialized executives were substantially under-represented. This work should prompt health care institutions to increase racial diversity in leadership.

Race and gender-based disparities in health care leadership^1–4 may negatively affect the health of marginalized patients.^5,6 Diverse leadership is an integral step in establishing equitable health care institutions that serve the needs of all community members.⁷ Many barriers prevent racialized people, women and gender nonbinary individuals from attaining leadership positions, including reduced access to networking opportunities, ^8–10 discrimination from patients and colleagues^2,11–13 and an institutional culture that views white, male leaders as most effective. ^14,15 The intersectional effects of discrimination may intensify these barriers for racialized women and nonbinary people.^16,17 Fundamentally, diversity and inclusion in our institutions is important on the basis of basic human rights for all people.¹⁸Health care leadership in Europe and the United States is thought to lack gender and racial diversity.^19–22 The degree to which these imbalances exist across Canadian health care institutions is not clear. Despite past evidence that men hold a disproportionate number of health care leadership positions in Canada,^23,24 a recent study noted gender parity among leaders of provincial and territorial ministries of health.²⁵ Among university faculty^26,27 and administration, ²⁸ racialized individuals appear to be under-represented, suggesting that a similar trend may exist in health care leadership.Race and gender can be studied in many ways.²⁹ Perceived race is a measure of “the race that others believe you to be,” and these assessments “influence how people are treated and form the basis of racial discrimination including nondeliberate actions that nonetheless lead to socioeconomic inequities.”²⁹ Similarly, perceived gender refers to an observer’s assumptions about a person’s gender, which can lead to differential and unfair treatment. ³⁰ Assessing perceived race and gender provides crucial insights into the ways in which social inequalities are informed and produced.²⁹ In this study, we sought to identify the perceived race and gender of hospital executive leaders in Canada and of nonelected leaders of the provincial and territorial health ministries. Furthermore, we wanted to analyze how the perceived racial composition of health care leadership compares with the racial composition of the population in the geographic areas that these leaders serve.     

Outcomes in patients with and without disability admitted to hospital with COVID-19: a retrospective cohort study

Background:Disability-related considerations have largely been absent from the COVID-19 response, despite evidence that people with disabilities are at elevated risk for acquiring COVID-19. We evaluated clinical outcomes in patients who were admitted to hospital with COVID-19 with a disability compared with patients without a disability.Methods:We conducted a retrospective cohort study that included adults with COVID-19 who were admitted to hospital and discharged between Jan. 1, 2020, and Nov. 30, 2020, at 7 hospitals in Ontario, Canada. We compared in-hospital death, admission to the intensive care unit (ICU), hospital length of stay and unplanned 30-day readmission among patients with and without a physical disability, hearing or vision impairment, traumatic brain injury, or intellectual or developmental disability, overall and stratified by age (≤ 64 and ≥ 65 yr) using multivariable regression, controlling for sex, residence in a long-term care facility and comorbidity.Results:Among 1279 admissions to hospital for COVID-19, 22.3% had a disability. We found that patients with a disability were more likely to die than those without a disability (28.1% v. 17.6%), had longer hospital stays (median 13.9 v. 7.8 d) and more readmissions (17.6% v. 7.9%), but had lower ICU admission rates (22.5% v. 28.3%). After adjustment, there were no statistically significant differences between those with and without disabilities for in-hospital death or admission to ICU. After adjustment, patients with a disability had longer hospital stays (rate ratio 1.36, 95% confidence interval [CI] 1.19–1.56) and greater risk of readmission (relative risk 1.77, 95% CI 1.14–2.75). In age-stratified analyses, we observed longer hospital stays among patients with a disability than in those without, in both younger and older subgroups; readmission risk was driven by younger patients with a disability.Interpretation:Patients with a disability who were admitted to hospital with COVID-19 had longer stays and elevated readmission risk than those without disabilities. Disability-related needs should be addressed to support these patients in hospital and after discharge.

A successful public health response to the COVID-19 pandemic requires accurate and timely identification of, and support for, high-risk groups. There is increasing recognition that marginalized groups, including congregate care residents, racial and ethnic minorities, and people experiencing poverty, have elevated incidence of COVID-19.^1,2 Older age and comorbidities such as diabetes are also risk factors for severe COVID-19 outcomes.^3,4 One potential high-risk group that has received relatively little attention is people with disabilities.The World Health Organization estimates there are 1 billion people with disabilities globally.⁵ In North America, the prevalence of disability is 20%, with one-third of people older than 65 years having a disability.⁶ Disabilities include physical disabilities, hearing and vision impairments, traumatic brain injury and intellectual or developmental disabilities.^5,6 Although activity limitations experienced by people with disabilities are heterogeneous,^5,6 people with disabilities share high rates of risk factors for acquiring COVID-19, including poverty, residence in congregate care and being members of racialized communities.^7–9 People with disabilities may be more reliant on close contact with others to meet their daily needs, and some people with disabilities, especially intellectual developmental disabilities, may have difficulty following public health rules. Once they acquire SARS-CoV-2 infection, people with disabilities may be at risk for severe outcomes because they have elevated rates of comorbidities.¹⁰ Some disabilities (e.g., spinal cord injuries and neurologic disabilities) result in physiologic changes that increase vulnerability to respiratory diseases and may mask symptoms of acute respiratory disease, which may delay diagnosis.^11–13 There have also been reports of barriers to high-quality hospital care for patients with disabilities who have COVID-19, including communication issues caused by the use of masks and restricted access to support persons.^14–17Some studies have suggested that patients with disabilities and COVID-19 are at elevated risk for severe disease and death, with most evaluating intellectual or developmental disability.^13,18–26 Yet, consideration of disability-related needs has largely been absent from the COVID-19 response, with vaccine eligibility driven primarily by age and medical comorbidity, limited accommodations made for patients with disabilities who are in hospital, and disability data often not being captured in surveillance programs.^14–17 To inform equitable pandemic supports, there is a need for data on patients with a broad range of disabilities who have COVID-19. We sought to evaluate standard clinical outcomes in patients admitted to hospital with COVID-19²⁷ (i.e., in-hospital death, intensive care unit [ICU] admission, hospital length of stay and unplanned 30-d readmission) for patients with and without a disability, overall and stratified by age. We hypothesized that patients with a disability would have worse outcomes because of a greater prevalence of comorbidities,¹⁰ physiologic characteristics that increase morbidity risk^11–13 and barriers to high-quality hospital care.^14–17     

Regional collaborative home-based palliative care and health care outcomes among adults with heart failure

BackgroundInnovative models of collaborative palliative care are urgently needed to meet gaps in end-of-life care among people with heart failure. We sought to determine whether regionally organized, collaborative, home-based palliative care that involves cardiologists, primary care providers and palliative care specialists, and that uses shared decision-making to promote goal- and need-concordant care for patients with heart failure, was associated with a greater likelihood of patients dying at home than in hospital.MethodsWe conducted a population-based matched cohort study of adults who died with chronic heart failure across 2 large health regions in Ontario, Canada, between 2013 and 2019. The primary outcome was location of death. Secondary outcomes included rates of health care use, including unplanned visits to the emergency department, hospital admissions, hospital lengths of stay, admissions to the intensive care unit, number of visits with primary care physicians or cardiologists, number of home visits by palliative care physicians or nurse practitioners, and number of days spent at home.ResultsPatients who received regionally organized, collaborative, home-based palliative care (n = 245) had a 48% lower associated risk of dying in hospital (relative risk 52%, 95% confidence interval 44%–66%) compared with the matched cohort (n = 1172) who received usual care, with 101 (41.2%) and 917 (78.2%) patients, respectively, dying in hospital (number needed to treat = 3). Additional associated benefits of the collaborative approach included higher rates of clinician home visits, longer time to first hospital admission, shorter hospital stays and more days spent at home.InterpretationAdoption of a model of regionally organized, collaborative, home-based palliative care that uses shared decision-making may improve end-of-life outcomes for people with chronic heart failure.

Innovative models of collaborative, interdisciplinary palliative care that use shared decision-making to promote goal- and need-concordant care are urgently needed to meet rising demand among people with heart failure.^1,2 Between 2010 and 2015, 75% of people with heart failure in Ontario died in hospital, despite 70% of people preferring an out-of-hospital death and 90% preferring end-of-life health care delivery at home.^3–5 Most people also prioritize improvements in quality of life at the end of life over extension of life.⁶ Admission to hospital near the end of life is often perceived as undesirable and may result in the provision of unwanted care, whereas home visits near the end of life tend to focus on comfort and are associated with higher rates of death at home.^4,5,7,8 These preferences are recognized at a system level, such that avoidance of unwanted health care and at-home death are considered quality indicators for end-of-life care.^9–11 However, delivering high-quality care for people with heart failure who are near the end of their life is challenging because of their unpredictable illness course and limited capacity of specialist palliative care.^4,12–14Many studies, including a recent meta-analysis, have shown that home-based palliative care is associated with improved quality of life and symptoms, reduced health care use and a higher likelihood of a home death among people with heart failure. ^{4,8,12,13,15,16} However, only 32% of people with heart failure received home-based palliative care near the end of life in Ontario.^4,8 Several randomized controlled trials explored the effects of collaborative care models for people with heart failure; ^12–16 the results were mixed regarding quality of life, symptoms and health care use.^13,17–21 Some trials reported that palliative care resulted in improvements in quality of life and reductions in burdensome symptoms and hospital admissions, whereas others reported no change in these outcomes.¹³ Most studies were single centre and none evaluated a model of regional organization and in-person home visits as a scalable approach.Given the need to address end-of-life care gaps for people with heart failure, we sought to determine whether regionally organized, collaborative, home-based palliative care (CHPC) — involving cardiology, primary care and palliative care — was associated with increased rates of out-of-hospital death among adults who died with heart failure.     

Recent trends in the prevalence of overweight and obesity among Canadian children

Background:Previous studies have shown an increase in the prevalence of overweight and obesity among Canadian children from 23.3% to 34.7% during 1978–2004. We examined the most recent trends by applying current definitions of overweight and obesity based on World Health Organization (WHO) body mass index (BMI) thresholds and recently validated norms for waist circumference and waist:height ratio.Methods:We examined directly measured height and weight data from the Canadian Community Health Survey (2004–2005) and the Canadian Health Measures Survey (2009–2013). We calculated z scores for BMI, height and weight based on the 2014 WHO growth charts for Canada, including the new extension of weight-for-age beyond 10 years. To calculate z scores for waist circumference and waist:height ratios, we used new charts from the reference population in the US NHANES III (National Health and Nutrition Examination Survey, 1988–1994).Results:Data were available for 14 014 children aged 3–19 years for the period 2004–2013. We observed a decline in the prevalence of overweight or obesity, from 30.7% (95% confidence interval [CI] 29.7% to 31.6%) to 27.0% (95% CI 25.3% to 28.7%) (p < 0.001) and stabilization in the prevalence of obesity at about 13%. These trends persisted after we adjusted for age, sex and race/ethnicity. Although they declined, the median z scores for BMI, weight and height were positive and higher than those in the WHO reference population. The z scores for waist circumference and waist:height ratio were negative, which indicated that the Canadian children had less central adiposity than American children in historic or contemporary NHANES cohorts.Interpretation:After a period of dramatic growth, BMI z scores and the prevalence of overweight or obesity among Canadian children decreased from 2004 to 2013, which attests to progress against this important public health challenge.Ongoing pan-Canadian surveys such as the Canadian Community Health Survey (CCHS) and Canadian Health Measures Survey (CHMS) are important to evaluate the health of our population using representative national samples.^1,2 Self-reported heights and weights replaced direct measurement during 1978–2004, which underestimated true rates of overweight and obesity.³ A subsequent comparison of directly measured heights and weights during the same period showed an alarming increase in the prevalence of overweight or obesity among Canadian children aged 2–17 years, from 23.3% (95% confidence interval [CI] 20.5% to 26.0%) to 34.7% (95% CI 33.0% to 36.4%) based on the new World Health Organization (WHO) definitions.¹In Canada, the definitions of overweight and obesity changed with the introduction of the 2010 WHO growth charts for Canada.^4,5 Previous definitions were based on body mass index (BMI) percentiles from the 2000 US Centers for Disease Control and Prevention (CDC) growth charts.⁶ In addition to revising these percentile thresholds, the WHO charts were based on a different reference population; as a result, the proportion of Canadian children classified as overweight or obese increased with the introduction of the new WHO charts.^1,7,8 Moreover, the absolute percentile thresholds now vary by age, with toddlers (2 to ≤ 5 yr) having higher thresholds to define overweight and obesity than older children (age > 5 to 19 yr).⁴Results from the United States have shown a decline in obesity rates among toddlers and a plateau in rates among older children;^9,10 stabilization has also been noted in other jurisdictions (e.g., Germany and Australia).^11–16 We undertook this study to determine the most recent trends in the prevalence of overweight and obesity among Canadian children using the current WHO weight charts for Canada applied to a representative sample of children.     

Geographic concentration of SARS-CoV-2 cases by social determinants of health in metropolitan areas in Canada: a cross-sectional study

Background:Understanding inequalities in SARS-CoV-2 transmission associated with the social determinants of health could help the development of effective mitigation strategies that are responsive to local transmission dynamics. This study aims to quantify social determinants of geographic concentration of SARS-CoV-2 cases across 16 census metropolitan areas (hereafter, cities) in 4 Canadian provinces, British Columbia, Manitoba, Ontario and Quebec.Methods:We used surveillance data on confirmed SARS-CoV-2 cases and census data for social determinants at the level of the dissemination area (DA). We calculated Gini coefficients to determine the overall geographic heterogeneity of confirmed cases of SARS-CoV-2 in each city, and calculated Gini covariance coefficients to determine each city’s heterogeneity by each social determinant (income, education, housing density and proportions of visible minorities, recent immigrants and essential workers). We visualized heterogeneity using Lorenz (concentration) curves.Results:We observed geographic concentration of SARS-CoV-2 cases in cities, as half of the cumulative cases were concentrated in DAs containing 21%–35% of their population, with the greatest geographic heterogeneity in Ontario cities (Gini coefficients 0.32–0.47), followed by British Columbia (0.23–0.36), Manitoba (0.32) and Quebec (0.28–0.37). Cases were disproportionately concentrated in areas with lower income and educational attainment, and in areas with a higher proportion of visible minorities, recent immigrants, high-density housing and essential workers. Although a consistent feature across cities was concentration by the proportion of visible minorities, the magnitude of concentration by social determinant varied across cities.Interpretation:Geographic concentration of SARS-CoV-2 cases was observed in all of the included cities, but the pattern by social determinants varied. Geographically prioritized allocation of resources and services should be tailored to the local drivers of inequalities in transmission in response to the resurgence of SARS-CoV-2.

The COVID-19 epidemic in Canada has varied in size and trajectory across provinces and large cities.^1,2 At the national level³ and within regions,^4,5 the burden of confirmed SARS-CoV-2 cases and severe COVID-19 outcomes has fallen disproportionately on socially and economically marginalized communities. ⁶ Social determinants of health refer to nonmedical factors influencing health outcomes, and structural determinants encompass cultural norms, policies and institutions that generate social stratification and determine socioeconomic position.^7,8 In Canada and elsewhere, data have consistently highlighted the importance of determinants such as household size and density, work in essential services and structural racism (measured by proxy) in the relative risk of COVID-19.^9–17Understanding the factors associated with geographic patterns of transmission within cities can help identify the populations and, specifically, the contexts with the greatest risks. Geographic analyses can enable better allocation of resources, tailoring of policies and implementation of context-specific strategies to more effectively and efficiently curb local transmission. ¹⁸ Although respiratory virus transmission is often geographically clustered within a city,¹⁹ the early public health response to SARS-CoV-2 transmission in Canada did little to take within-city clustering into account.^20,21 Similarly, few studies have quantified and compared the geographic concentration of SARS-CoV-2 cases by social determinants across Canada, and the extent to which the magnitude of inequalities might vary among cities and provinces.^19,22 We therefore sought to quantify and compare the magnitude of geographic concentration of SARS-CoV-2 cases by area-level social determinants of health across metropolitan areas in British Columbia, Manitoba, Ontario and Quebec, Canada.     

Association between long-term exposure to ambient air pollution and COVID-19 severity: a prospective cohort study

Background:The tremendous global health burden related to COVID-19 means that identifying determinants of COVID-19 severity is important for prevention and intervention. We aimed to explore long-term exposure to ambient air pollution as a potential contributor to COVID-19 severity, given its known impact on the respiratory system.Methods:We used a cohort of all people with confirmed SARS-CoV-2 infection, aged 20 years and older and not residing in a long-term care facility in Ontario, Canada, during 2020. We evaluated the association between long-term exposure to fine particulate matter (PM_2.5), nitrogen dioxide (NO₂) and ground-level ozone (O₃), and risk of COVID-19-related hospital admission, intensive care unit (ICU) admission and death. We ascertained individuals’ long-term exposures to each air pollutant based on their residence from 2015 to 2019. We used logistic regression and adjusted for confounders and selection bias using various individual and contextual covariates obtained through data linkage.Results:Among the 151 105 people with confirmed SARS-CoV-2 infection in Ontario in 2020, we observed 8630 hospital admissions, 1912 ICU admissions and 2137 deaths related to COVID-19. For each interquartile range increase in exposure to PM_2.5 (1.70 μg/m³), we estimated odds ratios of 1.06 (95% confidence interval [CI] 1.01–1.12), 1.09 (95% CI 0.98–1.21) and 1.00 (95% CI 0.90–1.11) for hospital admission, ICU admission and death, respectively. Estimates were smaller for NO₂. We also estimated odds ratios of 1.15 (95% CI 1.06–1.23), 1.30 (95% CI 1.12–1.50) and 1.18 (95% CI 1.02–1.36) per interquartile range increase of 5.14 ppb in O₃ for hospital admission, ICU admission and death, respectively.Interpretation:Chronic exposure to air pollution may contribute to severe outcomes after SARS-CoV-2 infection, particularly exposure to O₃.

By November 2021, COVID-19 had caused more than 5 million deaths globally¹ and more than 29 400 in Canada.² The clinical manifestations of SARS-CoV-2 infection range from being asymptomatic to multiple organ failure and death. Identifying risk factors for COVID-19 severity is important to better understand etiological mechanisms and identify populations to prioritize for screening, vaccination and medical treatment. Risk factors for severity of COVID-19 include male sex, older age, pre-existing medical conditions and being from racialized communities.^3–5 More recently, ambient air pollution has been implicated as a potential driver of COVID-19 severity.^6–10Long-term exposure to ambient air pollution, a major contributor to global disease burden,¹¹ could increase the risk of severe COVID-19 outcomes by several mechanisms. Air pollutants can reduce individuals’ pulmonary immune responses and antimicrobial activities, boosting viral loads.⁸ Air pollution can also induce chronic inflammation and overexpression of the alveolar angiotensin-converting enzyme 2 (ACE) receptor,⁷ the key receptor that facilitates SARS-CoV-2 entry into cells.^12,13 Exposure to air pollution contributes to chronic conditions, such as cardiovascular disease, that are associated with unfavourable COVID-19 prognosis, possibly owing to persistent immune activation and excessive amplification of cytokine development.¹⁰ Thus, greater exposure to long-term air pollution may lead to severe COVID-19 outcomes.Reports exist of positive associations between long-term exposure to particulate matter with diameters equal to or smaller than 2.5 or 10 μm (PM_2.5 and PM₁₀), ground-level ozone (O₃) and nitrogen dioxide (NO₂), and metrics of COVID-19 severity (e.g., mortality and case fatality rate).^8–10 However, most studies to date have used ecological and cross-sectional designs, owing to limited access to individual data, which leads to ambiguity in interpreting the results, thus hindering their influence on policy. ^6,14 Ecological designs do not allow for disentangling the relative impacts of air pollution on individual susceptibility to infection and disease severity.¹⁴ Residual confounding by factors such as population mobility and social interactions is also problematic. Therefore, a cohort study with data on individuals with SARS-CoV-2 is a more appropriate design.^6,14 Studies that have used individual data were conducted in specific subpopulations^15,16 or populations with few severe cases,¹⁷ or had limited data on individual exposure to air pollutants.¹⁸ In Canada, 1 ecological study found a positive association between long-term exposure to PM_2.5 and COVID-19 incidence,¹⁹ but no published study has explored the association between air pollution and COVID-19 severity.We aimed to examine the associations between long-term exposure to 3 common air pollutants (PM_2.5, NO₂ and O₃) and key indicators of COVID-19 severity, including hospital admission, intensive care unit (ICU) admission and death, using a large prospective cohort of people with confirmed SARS-CoV-2 infection in Ontario, Canada, in 2020. The air contaminants PM_2.5, NO₂ and O₃ are regularly monitored by the Canadian government, and are key pollutants that are considered when setting air-quality policies. They originate from varying sources (NO₂ is primarily emitted during combustion of fuel, O₃ is primarily formed in air by chemical reactions of nitrogen oxides and volatile organic compounds, and PM_2.5 can be emitted during combustion or formed by reactions of chemicals like sulphur dioxide and nitrogen oxides in air) and they may affect human health differently.^20,21,22     

Rates of health services use among residents of retirement homes in Ontario: a population-based cohort study

Background:Because there are no standardized reporting systems specific to residents of retirement homes in North America, little is known about the health of this distinct population of older adults. We evaluated rates of health services use by residents of retirement homes relative to those of residents of long-term care homes and other populations of older adults.Methods:We conducted a retrospective cohort study using population health administrative data from 2018 on adults 65 years or older in Ontario. We matched the postal codes of individuals to those of licensed retirement homes to identify residents of retirement homes. Outcomes included rates of hospital-based care and physician visits.Results:We identified 54 733 residents of 757 retirement homes (mean age 86.7 years, 69.0% female) and 2 354 385 residents of other settings. Compared to residents of long-term care homes, residents of retirement homes had significantly higher rates per 1000 person months of emergency department visits (10.62 v. 4.48, adjusted relative rate [RR] 2.61, 95% confidence interval [CI] 2.55 to 2.67), hospital admissions (5.42 v. 2.08, adjusted RR 2.77, 95% CI 2.71 to 2.82), alternate level of care (ALC) days (6.01 v. 2.96, adjusted RR 1.51, 95% CI 1.48 to 1.54), and specialist physician visits (6.27 v. 3.21, adjusted RR 1.64, 95% CI 1.61 to 1.68), but a significantly lower rate of primary care visits (16.71 v. 108.47, adjusted RR 0.13, 95% CI 0.13 to 0.14).Interpretation:Residents of retirement homes are a distinct population with higher rates of hospital-based care. Our findings can help to inform policy debates about the need for more coordinated primary and supportive health care in privately operated congregate care homes.

In the continuum of care services and settings for older adults lies home care at one end and long-term care at the other.¹ Home care services may include, but are not limited to, nursing care, personal care, homemaking services, and physiotherapy and occupational therapy for older adults who live independently in their community. Home care services are publicly funded under the Ontario Health Insurance Plan (OHIP).^2,3 Long-term care homes provide access to 24-hour nursing and personal care and operate at full capacity in Ontario, with waiting lists of 6 months or longer before an older adult in the community could receive an offer for a bed.^2,4 Retirement homes are thought to fit between home care and long-term care in this continuum.¹Retirement homes are referred to as assisted-living facilities in other North American jurisdictions, and they are private, congregate living environments that deliver supportive care to adults who are 65 years of age and older.^3,5,6 These homes are often marketed to provide a lifestyle and community, and they provide a range of assisted-living care services (e.g., meals, nursing services, etc.).^5,7 Retirement homes predominately operate on a private, for-profit business model, and the room, board and services are purchased by residents.^3,5 In Ontario, retirement homes are regulated through an independent, not-for-profit regulator (i.e., Retirement Homes Regulatory Authority [RHRA]).⁵ There are more than 700 licensed retirement homes in Ontario with over 70 000 available beds occupied by over 55 000 residents, which is comparable to the number of available beds in the long-term care sector.^3,5,6,8 Retirement homes are legislated differently from long-term care homes and primarily cater to adults who do not require 24-hour nursing care.^1,5,9 Unlike long-term care homes, no standardized reporting system is available to identify and describe residents of retirement homes.¹⁰ These residents are conceptualized as having fewer needs for care because they reside in a congregate care home to support independent living; however, this has been difficult to verify given there are no population-level data.A body of literature from the United States has described residents of assisted-living facilities and the sector,^11–17 but Canadian literature is comparatively nascent. Canadian studies have investigated transitions to a long-term care home, risk of hospital admission among those who live with dementia, and life events and health conditions associated with the transition to a congregate care setting.^7,9,18–20 At present, a Canadian population-level cohort of residents of retirement homes that describes the individual-level characteristics and use of health services of the older adults who reside in these homes appears to be lacking. Therefore, it is difficult to position this sector in the gradient of services and housing options for older adults in Canada.We created a population-level cohort of residents in retirement homes and sought to evaluate their rates of health services utilization relative to residents of long-term care homes and other populations of older adults (i.e., home care recipients and community-dwelling older adults) in Ontario.     

Impact of population mixing between vaccinated and unvaccinated subpopulations on infectious disease dynamics: implications for SARS-CoV-2 transmission

Background:The speed of vaccine development has been a singular achievement during the COVID-19 pandemic, although uptake has not been universal. Vaccine opponents often frame their opposition in terms of the rights of the unvaccinated. We sought to explore the impact of mixing of vaccinated and unvaccinated populations on risk of SARS-CoV-2 infection among vaccinated people.Methods:We constructed a simple susceptible–infectious–recovered compartmental model of a respiratory infectious disease with 2 connected subpopulations: people who were vaccinated and those who were unvaccinated. We simulated a spectrum of patterns of mixing between vaccinated and unvaccinated groups that ranged from random mixing to complete like-with-like mixing (complete assortativity), in which people have contact exclusively with others with the same vaccination status. We evaluated the dynamics of an epidemic within each subgroup and in the population as a whole.Results:We found that the risk of infection was markedly higher among unvaccinated people than among vaccinated people under all mixing assumptions. The contact-adjusted contribution of unvaccinated people to infection risk was disproportionate, with unvaccinated people contributing to infections among those who were vaccinated at a rate higher than would have been expected based on contact numbers alone. We found that as like-with-like mixing increased, attack rates among vaccinated people decreased from 15% to 10% (and increased from 62% to 79% among unvaccinated people), but the contact-adjusted contribution to risk among vaccinated people derived from contact with unvaccinated people increased.Interpretation:Although risk associated with avoiding vaccination during a virulent pandemic accrues chiefly to people who are unvaccinated, their choices affect risk of viral infection among those who are vaccinated in a manner that is disproportionate to the portion of unvaccinated people in the population.

The remarkable speed of vaccine development, production and administration during the COVID-19 pandemic is a singular human achievement.¹ While the ability to vaccinate to herd immunity has been held back by the increasing transmissibility of novel SARS-CoV-2 variants of concern (e.g., Delta and Omicron variants),^2,3 and global distribution of vaccines is inequitable,⁴ the effectiveness of SARS-CoV-2 vaccines in reducing severity of disease and disrupting onward transmission even when breakthrough infections occur is likely to have saved many lives. The emergence of the immune-evasive Omicron variant may undermine some of these gains, although provision of booster vaccine doses may restore vaccination to a high level of potency, and vaccines developed specifically to enhance immunity to the Omicron variant may emerge in 2022.^3,5–7However, antivaccine sentiment, fuelled in part by organized disinformation efforts, has resulted in suboptimal uptake of readily available vaccines in many countries, with adverse health and economic consequences.^8–10 Although the decision not to receive vaccination is often framed in terms of the rights of individuals to opt out,^11,12 such arguments neglect the potential harms to the wider community that derive from poor vaccine uptake. Nonvaccination is expected to result in amplification of disease transmission in unvaccinated subpopulations, but the communicable nature of infectious diseases means that this also heightens risk for vaccinated populations, when vaccines confer imperfect immunity. Although assortative (like-with-like) mixing¹³ is characteristic of many communicable disease systems and may be expected to limit interaction between vaccinated and unvaccinated subpopulations to some degree, the normal functioning of society means that complete like-with-like mixing is not observed in reality. Furthermore, the airborne spread of SARS-CoV-2^14–20 means that close-range physical mixing of people from vaccinated and unvaccinated groups is not necessary for between-group disease transmission.Historically, behaviours that create health risks for the community as well as individuals have been the subject of public health regulation. This is true of communicable infectious diseases but also applies to public health statutes that limit indoor cigarette smoking²¹ and legal restrictions on driving under the influence of alcohol and other intoxicants.^22,23Simple mathematical models can often provide important insights into the behaviour of complex communicable diseases systems.^13,24,25 To better understand the implications of the interplay between vaccinated and unvaccinated populations under different assumptions about population mixing, we constructed a simple susceptible–infectious–recovered model to reproduce the dynamics of interactions between vaccinated and unvaccinated subpopulations in a predominantly vaccinated population. We sought to contrast contribution to epidemic size and risk estimates by subpopulation, and to understand the impact of mixing between vaccinated and unvaccinated groups on expected disease dynamics.     

Patient–physician language concordance and quality and safety outcomes among frail home care recipients admitted to hospital in Ontario,Canada

Background:When patients and physicians speak the same language, it may improve the quality and safety of care delivered. We sought to determine whether patient–physician language concordance is associated with in-hospital and postdischarge outcomes among home care recipients who were admitted to hospital.Methods:We conducted a population-based study of a retrospective cohort of 189 690 home care recipients who were admitted to hospital in Ontario, Canada, between 2010 and 2018. We defined patient language (obtained from home care assessments) as English (Anglophone), French (Francophone) or other (allophone). We obtained physician language from the College of Physicians and Surgeons of Ontario. We defined hospital admissions as language concordant when patients received more than 50% of their care from physicians who spoke the patients’ primary language. We identified in-hospital (adverse events, length of stay, death) and post-discharge outcomes (emergency department visits, readmissions, death within 30 days of discharge). We used regression analyses to estimate the adjusted rate of mean and the adjusted odds ratio (OR) of each outcome, stratified by patient language, to assess the impact of language-concordant care within each linguistic group.Results:Allophone patients who received language-concordant care had lower risk of adverse events (adjusted OR 0.25, 95% confidence interval [CI] 0.15–0.43) and in-hospital death (adjusted OR 0.44, 95% CI 0.29–0.66), as well as shorter stays in hospital (adjusted rate of mean 0.74, 95% CI 0.66–0.83) than allophone patients who received language-discordant care. Results were similar for Francophone patients, although the magnitude of the effect was smaller than for allophone patients. Language concordance or discordance of the hospital admission was not associated with significant differences in postdischarge outcomes.Interpretation:Patients who received most of their care from physicians who spoke the patients’ primary language had better in-hospital outcomes, suggesting that disparities across linguistic groups could be mitigated by providing patients with language-concordant care.

A growing number of people in Canada (more than 6.1 million in 2016) are faced with the challenge of living in a situation in which their primary language is not spoken by most of the population and is not recognized as an official provincial or territorial language. ^1,2 We refer to this as a minority language situation, and such people include Francophones living outside of Quebec, Anglophones living in Quebec, and all residents of Canada whose primary language is a language other than English or French (allophones). Numerous studies have shown that people in North America with limited English proficiency generally have poorer access to health care and receive health care services of lower quality and safety, resulting in higher risk of adverse events and increased health resource use.^3–8 Despite these findings, few authors have considered the impact of patient–provider language concordance, whereby patients and providers have proficiency in a shared language.⁹ Studies in the United States have shown that patients with asthma who receive language-concordant primary care are less likely to omit medications, miss appointments or visit the emergency department.¹⁰ Patients with diabetes who receive language-concordant care have improved glycemic and low-density-lipoprotein control,^11,12 as well as increased participation in diabetic foot care programs.¹³ Although patient language is generally considered to be a nonmodifiable risk factor, language discordance represents a potentially modifiable variable, which could be the target of interventions (e.g., by referring patients to providers who have proficiency in their primary language).Frail patients are more likely to have communication problems and poor health outcomes than the general population; thus, language concordance may be particularly important in this patient population.^14,15 The risk of harm for frail, older patients has been attributed to medical complexity and multi-morbidity; ^16–18 however, since communication barriers also increase with age, older patients may also be more likely to experience harm because of poor patient–provider communication. ¹⁹ Most studies of language concordance have been limited to the primary care setting. We are aware of 2 studies conducted in the acute care setting, with 1 showing that Francophones residing in Ontario were less likely to experience harm when they were treated in hospitals that were required by law to provide services French. ^20,21We sought to compare the risk of adverse, hospital-related outcomes among frail patients living in Ontario, Canada, after stratifying by patient language and patient–physician language concordance or discordance. We hypothesized that patients receiving language-concordant care would have better outcomes than those receiving language-discordant care.     

Mediterranean diets and metabolic syndrome status in the PREDIMED randomized trial

Background:

Little evidence exists on the effect of an energy-unrestricted healthy diet on metabolic syndrome. We evaluated the long-term effect of Mediterranean diets ad libitum on the incidence or reversion of metabolic syndrome.

Methods:

We performed a secondary analysis of the PREDIMED trial — a multicentre, randomized trial done between October 2003 and December 2010 that involved men and women (age 55–80 yr) at high risk for cardiovascular disease. Participants were randomly assigned to 1 of 3 dietary interventions: a Mediterranean diet supplemented with extra-virgin olive oil, a Mediterranean diet supplemented with nuts or advice on following a low-fat diet (the control group). The interventions did not include increased physical activity or weight loss as a goal. We analyzed available data from 5801 participants. We determined the effect of diet on incidence and reversion of metabolic syndrome using Cox regression analysis to calculate hazard ratios (HRs) and 95% confidence intervals (CIs).

Results:

Over 4.8 years of follow-up, metabolic syndrome developed in 960 (50.0%) of the 1919 participants who did not have the condition at baseline. The risk of developing metabolic syndrome did not differ between participants assigned to the control diet and those assigned to either of the Mediterranean diets (control v. olive oil HR 1.10, 95% CI 0.94–1.30, p = 0.231; control v. nuts HR 1.08, 95% CI 0.92–1.27, p = 0.3). Reversion occurred in 958 (28.2%) of the 3392 participants who had metabolic syndrome at baseline. Compared with the control group, participants on either Mediterranean diet were more likely to undergo reversion (control v. olive oil HR 1.35, 95% CI 1.15–1.58, p < 0.001; control v. nuts HR 1.28, 95% CI 1.08–1.51, p < 0.001). Participants in the group receiving olive oil supplementation showed significant decreases in both central obesity and high fasting glucose (p = 0.02); participants in the group supplemented with nuts showed a significant decrease in central obesity.

Interpretation:

A Mediterranean diet supplemented with either extra virgin olive oil or nuts is not associated with the onset of metabolic syndrome, but such diets are more likely to cause reversion of the condition. An energy-unrestricted Mediterranean diet may be useful in reducing the risks of central obesity and hyperglycemia in people at high risk of cardiovascular disease. Trial registration: ClinicalTrials.gov, no. ISRCTN35739639.Metabolic syndrome is a cluster of 3 or more related cardiometabolic risk factors: central obesity (determined by waist circumference), hypertension, hypertriglyceridemia, low plasma high-density lipoprotein (HDL) cholesterol levels and hyperglycemia. Having the syndrome increases a person’s risk for type 2 diabetes and cardiovascular disease.^1,2 In addition, the condition is associated with increased morbidity and all-cause mortality.^1,3–5 The worldwide prevalence of metabolic syndrome in adults approaches 25%^6–8 and increases with age,⁷ especially among women,^8,9 making it an important public health issue.Several studies have shown that lifestyle modifications,¹⁰ such as increased physical activity,¹¹ adherence to a healthy diet^12,13 or weight loss,^14–16 are associated with reversion of the metabolic syndrome and its components. However, little information exists as to whether changes in the overall dietary pattern without weight loss might also be effective in preventing and managing the condition.The Mediterranean diet is recognized as one of the healthiest dietary patterns. It has shown benefits in patients with cardiovascular disease^17,18 and in the prevention and treatment of related conditions, such as diabetes,^19–21 hypertension^22,23 and metabolic syndrome.²⁴Several cross-sectional^25–29 and prospective^30–32 epidemiologic studies have suggested an inverse association between adherence to the Mediterranean diet and the prevalence or incidence of metabolic syndrome. Evidence from clinical trials has shown that an energy-restricted Mediterranean diet³³ or adopting a Mediterranean diet after weight loss³⁴ has a beneficial effect on metabolic syndrome. However, these studies did not determine whether the effect could be attributed to the weight loss or to the diets themselves.Seminal data from the PREDIMED (PREvención con DIeta MEDiterránea) study suggested that adherence to a Mediterranean diet supplemented with nuts reversed metabolic syndrome more so than advice to follow a low-fat diet.³⁵ However, the report was based on data from only 1224 participants followed for 1 year. We have analyzed the data from the final PREDIMED cohort after a median follow-up of 4.8 years to determine the long-term effects of a Mediterranean diet on metabolic syndrome.     

Post-acute health care burden after SARS-CoV-2 infection: a retrospective cohort study

Background:The post-acute burden of health care use after SARS-CoV-2 infection is unknown. We sought to quantify the post-acute burden of health care use after SARS-CoV-2 infection among community-dwelling adults in Ontario by comparing those with positive and negative polymerase chain reaction (PCR) test results for SARS-CoV-2 infection.Methods:We conducted a retrospective cohort study involving community-dwelling adults in Ontario who had a PCR test between Jan. 1, 2020, and Mar. 31, 2021. Follow-up began 56 days after PCR testing. We matched people 1:1 on a comprehensive propensity score. We compared per-person-year rates for health care encounters at the mean and 99th percentiles, and compared counts using negative binomial models, stratified by sex.Results:Among 531 702 matched people, mean age was 44 (standard deviation [SD] 17) years and 51% were female. Females who tested positive for SARS-CoV-2 had a mean of 1.98 (95% CI 1.63 to 2.29) more health care encounters overall per-person-year than those who had a negative test result, with 0.31 (95% CI 0.05 to 0.56) more home care encounters to 0.81 (95% CI 0.69 to 0.93) more long-term care days. At the 99th percentile per-person-year, females who tested positive had 6.48 more days of hospital admission and 28.37 more home care encounters. Males who tested positive for SARS-CoV-2 had 0.66 (95% CI 0.34 to 0.99) more overall health care encounters per-person-year than those who tested negative, with 0.14 (95% CI 0.06 to 0.21) more outpatient encounters and 0.48 (95% CI 0.36 to 0.60) long-term care days, and 0.43 (95% CI −0.67 to −0.21) fewer home care encounters. At the 99th percentile, they had 8.69 more days in hospital per-person-year, with fewer home care (−27.31) and outpatient (−0.87) encounters.Interpretation:We found significantly higher rates of health care use after a positive SARS-CoV-2 PCR test in an analysis that matched test-positive with test-negative people. Stakeholders can use these findings to prepare for health care demand associated with post-COVID-19 condition (long COVID).

The public health effects of the COVID-19 pandemic are difficult to overstate.¹ More than 600 million SARS-CoV-2 infections and 6.5 million deaths have been reported worldwide as of September 2022,² which are likely gross undercounts as many infections go undetected.³Long-term morbidity can be caused by SARS-CoV-2 infection.^4–9 In the first pandedmic wave, as many as 27% of people admitted to hospital died or were readmitted within 60 days, and as many as 70% of people who were not admitted to hospital reported at least 1 symptom 4 months after infection.^10,11 By the World Health Organization (WHO) definition, about 10%–20% of those infected acquire a post-COVID-19 condition (long COVID).^12,13Analysis of 10 prospective surveys and the medical records of 1.1 million patients with COVID-19 diagnosis codes before the emergence of the Omicron variant showed similar findings: 7.8%–17% had symptoms 12 weeks after self-reported COVID-19, with 1.2%–4.8% reporting debilitating symptoms.¹⁴ Estimates of long COVID vary by methodology (e.g., definitions of initial infection and timing of symptoms, timing of data collection), but risk is thought to be influenced by infection severity, type of variant, patient characteristics, vaccination¹⁵ and, potentially, previous infection.¹⁶ Because each new SARS-CoV-2 infection carries some risk of long COVID, everyone remains at risk for developing the condition.Health care funders, policy-makers and clinicians need a clear understanding of the impact of long COVID on use of health care resources to allocate resources equitably now and plan for future needs.¹⁷ We sought to quantify the post-acute burden of health care use after SARS-CoV-2 infection among community-dwelling adults in Ontario.     

Body mass index and all-cause mortality in a large Chinese cohort

Background

Obesity is known to be associated with an increased risk of death, but current definitions of obesity are based on data from white populations. We examined the association between body mass index (BMI) and the risk of death in a large population of adult Chinese people.

Methods

We examined the association between body mass index (BMI) and all-cause mortality prospectively among 58 738 men and 65 718 women aged 20 years and older enrolled in 1998–1999 from four national health screening centres in Taiwan. We used Cox proportional hazards regression analyses to estimate the relative risks of all-cause mortality for different BMI categories during a maximum follow-up of 10 years.

Results

A total of 3947 participants died during the follow-up period. The lowest risk of death was observed among men and women who had a BMI of 24.0–25.9 (mean 24.9). After adjustment for age, smoking status, alcohol intake, betel-nut chewing, level of physical activity, income level and education level, we observed a U-shaped association between BMI and all-cause mortality. Similar U-shaped associations were observed when we analyzed data by age (20–64 or ≥ 65 years), smoking (never, < 10 pack-years or ≥ 10 pack-years) and presence of a pre-existing chronic disease, and after we excluded deaths that occurred in the first three years of follow-up.

Interpretation

BMI and all-cause mortality had a U-shaped association among adult Chinese people in our study. The lowest risk of death was among adults who had a BMI of 24.0–25.9 (mean 24.9). Our findings do not support the use of a lower cutoff value for overweight and obesity in the adult Chinese population.The prevalence of obesity has dramatically increased in past decades in both developed and developing countries. The World Health Organization (WHO) reported that 1.6 billion adults are overweight and at least 400 million are obese.¹ The WHO further predicted that by the year 2015, about 2.3 billion adults will be overweight and more than 700 million will be obese.¹ In Taiwan, according to a national survey performed between 1993–1996 and 2005–2008, the prevalence of overweight and obesity (defined as body mass index [BMI] ≥ 24 kg/m²) had increased dramatically, from 33.4% to 50.8% among men and from 31.7% to 36.9% among women.²Overweight and obesity have been recognized as important and independent risk factors for many chronic diseases such as diabetes mellitus, hypertension, stroke, cardiovascular diseases and malignant diseases.^3–7 Substantial epidemiologic evidence shows that obesity is associated with an increased risk of cardiovascular-related and all-cause mortality.^8,9 Therefore, obesity has become a major public health problem around the world.Current definitions of obesity and overweight in adults are based on data from white populations. The WHO has proposed another definition for Asian people, but most of the data it used were from cross-sectional studies.¹⁰ One study showed that, for a given BMI, Asian people had higher body fat than white people.¹¹ Furthermore, the association between BMI and all-cause mortality has been reported to be J-shaped or U-shaped. Most of the studies involved white people, with only a few involving Asian populations. Gu and colleagues reported a U-shaped association between BMI and all-cause mortality among Chinese people.¹² However, they included only middle-aged adults over 40 years old and not all adults over 20 years.We designed a large prospective cohort study to assess the association between BMI and all-cause mortality in a nationwide representative sample of Chinese adults over 20 years old in Taiwan. We also intended to find the optimal BMI cutoff values for overweight and obesity among Chinese adults.