key: cord-0919716-6xm4mnro
authors: Lin, Shen (Lamson)
title: Intersectionality and inequalities in medical risk for severe COVID-19 in the Canadian Longitudinal Study on Aging
date: 2020-09-24
journal: Gerontologist
DOI: 10.1093/geront/gnaa143
sha: 9b50549354e69a36e370c410da4c4ef4643a7c27
doc_id: 919716
cord_uid: 6xm4mnro

BACKGROUND AND OBJECTIVES: Older populations with underlying medical conditions are at higher risk of COVID-19 severity and mortality once infected. Intersectional gerontology considers the compounding effects of multiple forms of social inequity. This study explores how racial-nativity status, family income, education level and the intersecting profile of these three social standings stratify differential patterns of chronic conditions among Canadians aged 45 years and older. RESEARCH DESIGN AND METHODS: Using the baseline Canadian Longitudinal Study on Aging (n = 29,748), multinomial logistic regression analyses were conducted to estimate multivariable-adjusted odds of having one and/or two (≤ 2) or multiple (≥3) medical conditions (i.e., diabetes, asthma, cancer, previous heart attack, cardiovascular disease, kidney disease, hypertension, chronic obstructive pulmonary disease, and obesity) based on socio-demographic characteristics. RESULTS: There were significant racial-nativity disparities and social-class gradients in multimorbidity. The odds of having ≥3 medical conditions were greater for Black immigrants (OR=1.79, 95% CI=1.13, 2.82), South Asian immigrants (OR=1.49, 95% CI=1.02, 2.19) and close to double for Aboriginal Canadians (OR=1.96, 95% CI=1.37, 2.80) relative to Canadian-born Whites. Black, South Asian and Aboriginal populations from disadvantaged socioeconomic backgrounds had the highest odds of having ≥3 medical conditions (OR=3.50, 95% CI=1.41, 8.70). DISCUSSION AND IMPLICATIONS: Despite a universal health system, marginalized older Canadians who are racialized foreign-born, less educated, and/or low-income have a higher prevalence of multimorbidity that are associated with COVID-19 severe illness and mortality. Upstream health policy and social care tackling intersecting structural inequities should be undertaken to prevent increasing multimorbidity among underserved aging populations.

A c c e p t e d M a n u s c r i p t 4 Background Although the novel coronavirus disease 2019 can infect anyone, racialized and impoverished populations carry a disproportionate burden of the disease (Abrams & Szefler, 2020; Ahmed, Ahmed, Pissarides, & Stiglitz, 2020; Bambra, Riordan, Ford, & Matthews, 2020) , which has heightened awareness of existing health gaps between the privileged social groups and those vulnerable populations. Similar to previous outbreaks of influenza and severe acute respiratory syndrome (Quinn et al., 2011) , what the COVID-19 pandemic brings to the forefront is that both exposure to health hazards and access to health-enhancing resources are fundamentally different based on race, nativity, class and many other social positions (Wright, Steptoe, & Fancourt, 2020) , also known as social determinants of health (Marmot, 2005) . A burgeoning body of evidence has demonstrated overrepresentation of racialized, low-income, and other socially marginalized populations among cases of and deaths from COVID-19 across the globe. For example, in the USA, counties in which the majority of the population are Black have three times the prevalence of COVID-19 and six times the fatality rate of White majority counties (Dyer, 2020) . These Black-White gaps in COVID-19 mortality are especially prominent among middle-aged Americans (Ford, Reber, & Reeves, 2020) . In the UK, persons with disadvantaged socioeconomic backgrounds suffered from greater adversities in the lockdown due to COVID-19, including higher rates of job loss, food insecurity, lower access to medication, and inability to pay bills (Wright et al., 2020) .

The framework of the World Health Organization (WHO) Commission on Social Determinants of Health (SDoH) asserts that social vulnerabilities, produced by one's multiple social locations in hierarchical social orders (Bourgois, Holmes, Sue, & Quesada, 2017) , are root causes of population health inequalities in the upstream casual pathway to ill-health (WHO, 2008) . In the case of the COVID-19 pandemic, the distal impact of social vulnerabilities, such as racial stratification and poverty, could be transmitted through many downstream channels (Krieger, Nancy, 2005; A c c e p t e d M a n u s c r i p t 5 Phelan, 1995; Palmer, Ismond, Rodriquez, & Kaufman, 2019) . These proximal risk factors may include underlying medical conditions (e.g., heart disease, hypertension, chronic kidney disease, asthma, obesity) that have been associated with critical illness among COVID-19 patients (Bello-Chavolla et al., 2020; Petrilli et al., 2020) . For example, previous studies have suggested that the most deprived populations were 60% more likely to develop chronic kidney disease than their wealthiest counterparts (Webster, Nagler, Morton, & Masson, 2017) . Aboriginal populations in Canada and Australia, Hispanics in the USA, and Black people in the UK had a higher likelihood of chronic kidney disease than their White peers (Morton et al., 2016) . Likewise, social inequalities in cardiovascular disease (Harper, Lynch, & Smith, 2011 ), cancers (Hovanec et al., 2018 Merletti, Galassi, & Spadea, 2011) , body-mass index (Bann, Johnson, Li, Kuh, & Hardy, 2018; Kim, Kawachi, Coull, & Subramanian, 2018) , and asthma-related mortality (Gupta, Mukherjee, Sheikh, & Strachan, 2018) are well documented across the life course. This research on social inequalities underscores the necessity of considering social conditions in which people live and grow to address population health disparities.

Previous research has demonstrated the individual-level etiologic mechanism to explain how social inequalities could "get under the skin" via biological regulatory systems (Seeman, Epel, Gruenewald, Karlamangla, & McEwen, 2010) . Adversities and stressors faced by vulnerable populations, including food and employment insecurity, precarious housing and barriers to accessing quality health and social services (Raphael, Curry-Stevens, & Bryant, 2008) , impose physiological and psychological harm (Kawachi, Subramanian, & Almeida-Filho, 2002) . Mounting evidence (Seeman et al., 2010) suggests that individuals in disadvantaged social conditions are more susceptible to circumstances that exceed their coping resources and thus are chronically exposed to unmanaged stress (Phelan & Link, 2005; Phelan, Link, & Tehranifar, 2010; Williams, Lawrence, & Davis, 2019) .

Exposure to chronic stress increases the allostatic load, a measure of multiple physiologic parameters such as blood pressure and cholesterol levels (Geronimus, Hicken, Keene, & Bound, M a n u s c r i p t 6 2006), resulting in a wide range of negative health and illness outcomes (James et al., 2006; Seeman et al., 2010) .

While health inequalities are well documented in relation to race/ethnicity (Siddiqi, Shahidi, Ramraj, & Williams, 2017; Veenstra, 2009; Veenstra & Patterson, 2016 ), nativity (Davison et al., 2020 and socioeconomic status (Minkler, Fuller-Thomson, & Guralnik, 2006) , prior research has typically examined these health differences separately. In immigrant health literature, the conventional approach tends to homogenise the experience of racialized and White immigrants (Brown, 2018) . The intersectionality lens of race, immigration and old age has been largely overlooked (Gkiouleka, Huijts, Beckfield, & Bambra, 2018) . Ignoring the heterogeneity among immigrant populations is a serious shortcoming because race/ethnicity, language and cultural differences may cumulatively influence the health and wellbeing of immigrants who are aging in a foreign land (Ferrer, Grenier, Brotman, & Koehn, 2017) . As such, intersectionality theory has much to offer to population health research because it unpacks various minority struggles that are often obscured within a discourse of multiculturalism and diversity (Hankivsky & Christoffersen, 2008) .

Therefore, an investigation of how race, nativity and social class combine to shape health outcomes in late life is warranted.

The arrival of COVID-19 in Canada presents an unprecedented public health challenge, with over one hundred thousand confirmed cases, eight thousand death to date (Public Health Agency of Canada, 2020a), and a crude case fatality rate of 4.9% on April 22, 2020 (Abdollahi, Champredon, Langley, Galvani, & Moghadas, 2020) , which is substantially greater than seasonal influenza death rate of approximately 0.1% (Jordan, Adab, & Cheng, 2020) . Although the Canadian government has taken rapid response measures to slow the rate of COVID-19 infection and to mitigate the risk of A c c e p t e d M a n u s c r i p t 7 severe complications (Public Health Agency of Canada, 2020b), few studies have been devoted to identifying which older populations in Canada are facing greater challenges because of the preexisting epidemics of chronic disease. Given that Canada does not collect socio-demographic and race-based data on COVID-19 cases at the federal level (Osman, 2020), there is no investigation of the impact of social inequalities on COVID-19 testing, infection and mortality rates in Canada.

Alternatively, using observational databases that captured demographic patterns and clinical characteristics of the Canadian population in previous years could offer reasonable estimates for health risk assessment in the ongoing pandemic. This retrospective approach to evaluate population at risk has been applied in preventive science (Gibson & Greene, 2020; Raifman & Raifman, 2020) Intersectional gerontology as a critical lens illuminates the compounding effects of inequity and places the experience of those inequities within the context of systemic oppression among older persons (Koehn, Neysmith, Kobayashi, & Khamisa, 2013) . Guided by the intersectionality lens of SDoH, this study aimed to explore the differential patterns of pre-existing multimorbidity known to be associated with COVID-19 mortality by (1) racial-nativity status; (2) family income; (3) education;

and (4) the intersecting profile of these three social positionings. This study has important implications for health equity policy and provides a timely frame of reference for public health decision-makers, which may help to improve surveillance systems, allocate critical care interventions, advance health equity and mitigate the pandemic's long-term societal harms.

Recognizing that minority communities with adverse social determinants may be more susceptible to severe forms of COVID-19 (Abrams & Szefler, 2020; Ahmed et al., 2020; Dyer, 2020; Wright et al., 2020) , the present study examined the following three hypotheses.

A c c e p t e d M a n u s c r i p t 8 H1 Racial-nativity inequalities hypothesis: Older adults who are racialized and foreign-born would be more likely to have pre-existing medical conditions, compared to Canadian-born Whites.

Older adults who are less educated and/or lowincome would be more likely to have pre-existing medical conditions, compared to their peers in higher social class.

Multiple jeopardies of three disadvantaged social positions in terms of racial-nativity, income and education would put older adults at a higher risk of having pre-existing medical conditions, compared to their peers with relative social privilege.

This study used the comprehensive cohort data (n=30,163) from the baseline collection (2012) (2013) (2014) (2015) of the Canadian Longitudinal Study on Aging (CLSA), a unique population-based study of community-dwelling Canadians aged 45 to 85 who will be followed for 20 years across 10 provinces (Raina et al., 2009) . The detailed methodology of the CLSA has been previously published (Davison et al., 2020; Lin et al., 2020) . The CLSA excludes Canadians residing in long-term care facilities, on First Nations reserves, members of the armed forces, non-English or non-French speakers, and those with dementia. The comprehensive cohort data were collected through in-home face-to-face interviews and at 1 of 11 data collection sites. In this study, participants were excluded if they did not respond to the survey questions about all of the underlying medical conditions (n=67), racial-nativity status (n=125) or relationship status (n=90). This yielded to a final sample size of 29,748 respondents. M a n u s c r i p t 9

Pre-existing medical conditions as risk factors for COVID-19 severity. This study estimated the proportion of adults having one or more out of nine underlying medical conditions that have been identified as clinical risk factors for severe illness from COVID-19 by the U.S. Centers for Disease Control and Prevention (Raifman & Raifman, 2020) . Consistent with recent U.S. studies (Gibson & Greene, 2020; Raifman & Raifman, 2020) , these nine physician-diagnosed medical conditions include: diabetes, asthma, cancer, previous heart attack or myocardial infarction, kidney disease, cardiovascular disease (angina or chest pain due to heart disease), hypertension, chronic obstructive pulmonary disease (COPD), and obesity (as assessed by body mass index >30 kg/m2).

The outcome measure was an aggregated variable grouped into 3 levels: none; ≤ 2 medical conditions; and ≥ 3 medical conditions (i.e., multimorbidity).

In light of the WHO's SDoH paradigm (Marmot, 2005) , racial-nativity status, income and education levels were selected as three key equity stratifiers in this study. Racial-nativity status was classified into 11 groups, including Canadian-born (CB) categories (White, non-White), aboriginal Canadians (including First Nations, Inuit and Métis) and eight foreign-born (FB) categories by their self-identified racial backgrounds (i.e., White, Black, Latin American, East Asian, West Asian, South Asian, Southeast Asian and others) (Gkiouleka et al., 2018) .

Because of small numbers, Filipinos were combined with Southeast Asians and Arabs with West Asians (Quan et al., 2006) . The operationalization of racial-nativity status recognizes race as a social construct rooted in broader structures of racial oppression (Krieger, N., 2000) and immigration as a complete realignment of life (Castañeda et al., 2015) . Due to the small sample size (n=242), detailed ethnic groups could not be disaggregated among Canadian-born non-Whites. Highest level of education was divided into four categories: grade 11 or less, high-school graduate, some college, and post-secondary education. Income was defined as the household income received by all family A c c e p t e d M a n u s c r i p t 10 members in the past 12 months (<$20k; $20k to <$50k; $50k to <$100k; $100k to <$150k; ≥$150k, and non-response).

Intersecting social vulnerability. Informed by the intersectionality lens to examine multiple forms of marginalization (Gkiouleka et al., 2018; Kapilashrami & Hankivsky, 2018; Shi & Stevens, 2005) , a cumulative profile of social vulnerabilities was created to identify respondents in one or more out of three disadvantaged social positions: racial-nativity minorities status (South Asian immigrants, Black immigrants, aboriginal Canadians), middle-to-lower annual household income (<$50k), less educated (≤ high school graduates). These three racial categories were selected as they have been consistently associated with adverse health outcomes (e.g., hypertension, diabetes) in Canada (Chiu, Maclagan, Tu, & Shah, 2015; Ramraj et al., 2016; Veenstra, 2009 ). Since only 4.4% respondents with <$20k household income, we adopted <$50k as the cut-off value that was less than the median after-tax income for senior families ($63,500) reported in 2018 Canadian income survey.

To consider other potential confounders and/or effect modifiers known to be involved in the ageing process, control variables include social demographics (age groups, sex, marital status, retirement status), health indicators (chronic pain, functional limitation), a behavioral health risk factor (never-vs.-ever smokers using the cut-off value of 100 cigarettes per lifetime), and health care utilization (past-year contact with general practitioners). Functional limitation assessed respondent's capacity to perform basic and instrumental activities of daily living (ADLs) such as eating or bathing (Fillenbaum & Smyer, 1981) and the summation index was dichotomized into two levels of ADLs impairments.

A c c e p t e d M a n u s c r i p t 11

Weighted statistics were applied to describe sample characteristics by racial-nativity status.

The weights provided by CLSA were normalized to produce population-representative estimates corrected for the sample size and nonresponse bias. First, chi-square tests were used to test the statistical differences at the bivariate level. Second, multinomial logistic regression models were undertaken to calculate multivariable-adjusted odds ratio (OR) and 95% confidence intervals (95% CI) of having ≤ 2 and ≥ 3 medical conditions (risk factors) for racial-nativity, income and educational levels, after controlling for known health determinants. Third, multinomial logistic regression analysis was for the same outcome measure included the cumulative profile of social vulnerabilities as the key explanatory variable adjusted for covariates. Lastly, a sensitivity test was conducted for two stratified samples by age (middle-aged group: 45-65; older-aged group: 66-85) to examine whether racial health inequalities are consistent between younger and older generations. Statistical analyses and data management were performed using SPSS software package, Version 26 (IBM Corp., Armonk, N.Y., USA). A p-value <.05 (two-tailed) was considered statistically significant.

[Editor: please insert Table 1 & Figure 1 here from the Appendix] Table 1 summarizes the sample characteristics for all variables by racial-nativity status. The sample (n=29,748) mainly consisted of respondents who were Canadian-born White (80%), aged 45-76 years (82.5%), earning > $50,000/year (67.3%), in a relationship (68.7%), had a post-secondary diploma or degree (77.5%), had no/mild ADLs impairment (98.6%), had no chronic pain (76.4%) and had past-year contacts with family doctors (84.1%). The sex distribution was even (men: 49%; women: 51%). Around half of the sample was ever smoker (50.4%) and retired (56.8%).

Approximately 68% of the middle-aged and older Canadians (n=20,248) had at least one pre-existing A c c e p t e d M a n u s c r i p t 12 medical condition that had placed them at higher risk of severe illness from COVID-19. Fourteen percent of respondents (n=5,033) had three or more of these medical conditions. Among racial immigrants (average time since immigration: 42.7 years), aboriginal populations, Black immigrants and South Asian immigrants were over-represented in low-income group (<$20k: 7.4%, 6.7%, 8.4%) compared to Canadian-born Whites (4.5%). Only 4.6% (n=244) of immigrants had lived in Canada fewer than 10 years. All aforementioned categorical indicators were significantly linked to the underlying medical conditions and thus were included the multivariable analyses. Figure 1 illustrates weighted prevalence of nine specific underlying medical conditions stratified by race-nativity status. The most prevalent medical condition for the overall sample was hypertension (32%), followed by obesity (27.5%), diabetes (15.4%), asthma (13.6%), cancer (12.5%), COPD (4.8%), previous heart attack (3.6%), angina (3.5%) and kidney disease (2.6%). Among racial communities, aboriginal populations, Black immigrants and South Asian immigrants had the highest prevalence of obesity (40.3%), hypertension (44.6%) and diabetes (31.2%), respectively. All differences in these nine medical conditions by race-nativity status were significant based on chisquare tests (p<0.05), except for kidney disease (p=0.30) and heart attack (p=0.12). Table 2 displays the unweighted counts of overall sample characteristics, weighted prevalence and multivariable-adjusted odds of having one and/or two (≤ 2) and multiple (≥3) underlying medical conditions. Figure 2 shows a series of eight figures including four bar charts of weighted prevalence (Figure 2A , 2C, 2E, 2G) and four odds ratio plots of logistic-regression analyses ( Figure 2B , 2D, 2F, 2H) stratified by each social position. All selected covariates were associated with multimorbidity and thus they were retained in the statistical model (see Table 2 

As shown in Table 2 , even after adjusting for confounders, several minority populations had significantly elevated risk of having multiple medical conditions. Figure 2A and 2B display these racial-nativity gaps in multimorbidity prevalence and odds ratios. 

A salient social-class gradient in underlying medical conditions of severe COVID-19 illness stood out, especially among those with ≥ 3 medical conditions (see Table 2 ). As shown in Figure 2C and 2D, there was a dose-response relationship between family income level and multiple medical A c c e p t e d M a n u s c r i p t 14 conditions. In other words, with decreasing income, the odds of reporting ≥ 3 medical conditions significantly escalated, ranging from middle-income persons with 17% higher odds (OR=1.17, 95% CI=1.01, 1.34) to individuals in the poorest bracket having close to two-and-a-half greater odds (OR=2.44, 95% CI=1.96, 3.04), compared to the wealthiest respondents. Likewise, as illustrated in Figure 2E and 2F, there was a similar dose-response pattern between educational attainment and multiple medical conditions. As education level decreased, a greater proportion of respondents reported having ≥ 3 medical conditions (ORs range from 1.21 to 2.10), among whom the odds of having ≥ 3 medical conditions in the lowest educational group rose more than two times (OR=2.10, 95% CI=1.76, 2.50) in comparison to their peers in the highest educational bracket. The educational gradient was also visible in the odds of having ≤ 2 medical conditions (ORs range from 1.11 to 1.15), whereas the income gradient was less pronounced. The current investigation examined the relationship between three sources of social status (i.e., income, education and racial-nativity status) and the prevalence of having multiple medical conditions among Canadians who aged 45 years and older. These relationships may shed some light on who may have higher susceptibility to negative sequelae of COVID-19 illness. The findings reveal that multimorbidity is more prevalent among marginalized people who are Aboriginal, South Asian immigrants, Black immigrants, those with less educational attainment, and those living in lowincome households in comparison to those who are White, more educated and/or wealthier. The results of this research indicate that health inequities by social status exist in Canada as they do in the US (Raifman & Raifman, 2020) . Despite the fact that Canada has a universal health system and the USA has a market-oriented health system, Canada is not immune to structural drivers of health disparities (Ramraj et al., 2016; Siddiqi et al., 2017) . This study extends existing research on the healthy immigrant effect (HIE), a phenomenon that immigrants appear to in better health than the host populations, resulting from the selective immigration policy and mandatory health screening (Vang et al., 2017; Kobayashi & Prus, 2012) . The findings show that, relative to Canadian-born Whites, White and East Asian immigrants have a persistent health advantage, whereas Black and South Asian immigrants have significant worse health consequences and other racialized immigrants (i.e., Latin American, West Asian and Southeast Asian) tend to have comparable health profiles. This study challenges previous studies that may overgeneralize the HIE experience to racial minority immigrants in mid-to-late life (McDonald & Kennedy, 2004; Newbold, 2006) . In line with intersectionality research (Adjei, Adu, & Ackah, 2020; Brown, 2018; Kobayashi & Prus, 2012) , this study suggests that, for Black and South Asian immigrants, any immigrant health advantage may be offset by cumulative exposure to stressors (e.g., language difficulties, racism, cultural misunderstanding) in the post-migration period that lead to the accumulation of chronic conditions at later life stages (Bailey et al., 2017) .

The findings of our study are particularly relevant in the context of COVID-19 pandemic, where racialized and socially disadvantaged individuals experience structural inequities that increase the risk of exposure to pathogens (Wright et al., 2020), such as precarious work which require extensive interaction with the public (e.g. retail positions, cleaners, or cashiers), the need to use public transit rather than driving a car ( Van et al., 2020) , and living in overcrowded housing that makes self-isolation difficult (Selden & Berdahl, 2020) . Racialized populations are also overrepresented in frontline healthcare occupations including personal support worker and nursing (Raphael et al., 2008) . Blacks and Aboriginals in Canada are more prone to everyday discrimination A c c e p t e d M a n u s c r i p t 17 associated with chronic conditions (Siddiqi et al., 2017) and the experiences of othering may be further reinforced during the COVID-19 crisis (Devakumar, Shannon, Bhopal, & Abubakar, 2020).

Many of the First Nations, Inuit and Métis communities locate in remote areas resulting in geographical barriers to accessing timely medical care.

This study has several strengths, including its large sample size, its ability to include measures of intersecting social positions, its pragmatic categorization of diverse racialized immigrant populations and its attention to the clustering of underlying medical conditions. However, several methodological flaws and biases limited the generalisability of this study. Relatively small sample sizes of certain minority groups and low response rates in the CLSA have weakened the study's power. This study relied on self-reported survey data and may induce recall bias. The non-random sample seems to be unusually well-educated, perhaps due to self-selection. The reported rates of chronic diseases from this healthy sample may, therefore, be lower than actual prevalence in the Canadian population. This is particularly true for immigrants who were more likely to have had postsecondary education than Canadian-born Whites in this sample and thus survival bias may be stronger in these populations that could lead to an underestimation of racial-nativity inequalities.

The CLSA baseline survey does not cover all underlying conditions (i.e., liver disease, HIV, hepatitis) identified by the CDC or any direct measures of COVID-19 confirmed cases. Because of the sensitive nature of income reporting, the CLSA only collected family income information in categorical format, which is subject to an unquestioned assumption that material resources are distributed equally according to needs within the household. The absence of absolute income value precludes further calculation of income-to-needs ratios to adjust for the poverty threshold and family size. Since CLSA only includes participants speaking English or French, immigrants facing language barriers were less likely to be surveyed and at elevated risk of under-detection of health problems. In addition, the CLSA excludes individuals residing in nursing home where are the loci of 

Overall, this nationwide study has demonstrated inequalities by race, nativity, income and education in the prevalence of pre-existing medical conditions associated with greater COVID-19 severity among middle-aged and older Canadians in a universal health system. Such multimorbidity inequalities are potentially amenable to policy beyond the scope of the traditional health sector.

Policies that redistribute resources could address this problem (Phelan et al., 2010) , for example, by expanding social welfare programs (e.g., old-age pension, unemployment insurance, public housing).

Such policies could tackle upstream social inequities and enhance vulnerable individuals' capacity to cope with day-to-day life challenges during a public health emergency (Wang & Tang, 2020) . Another rapid approach lies in redirecting health-enhancing resources to people living in lower-income and minority communities. This initiative involves the formulation of community outreach and health screening programs targeted for vulnerable older adults that are potentially left behind by the M a n u s c r i p t 32 Notes: FB=Foreign-born; CB=Canadian-born; Unwtg.= Unweighted; Wtg.=Weighted; OR=odds ratio; 95%CI=95% Confidence Interval; GP=general practitioners; ADLs=Activities of Daily Living Scales; Statistics for multinominal logistic regression that reach the 0.05 level of significance are bolded (Nagelkerke R 2 = 0.14). Cumulative profile was tested in a separated identical analysis adjusted for same covariates (not shown; Nagelkerke R 2 = 0.13). Cumulative profile=a sum of three social positions (R=South Asian, Black or Aboriginals; and/or I=household income <$50k; and/or E=≤ high school graduates).

M a n u s c r i p t 34 Figure 1 Weighted prevalence of 9 specific medical conditions as risk factors of severe COVID-19 illness by racenativity status in the CLSA, persons aged 45-85 years (n=29,748)

Notes: FB=Foreign-born; CB=Canadian-born; CLSA= Canadian Longitudinal Study on Aging (baseline comprehensive cohort). COPD=chronic obstructive pulmonary disease. All differences by race-nativity status reached the 0.05 level of statistically significance in the chi-square test (p<0.05), except for kidney disease (p=0.30) and heart attack (p=0.12).

*P <0.05; **P <0.01; ***P <0.001; ns=not significant. Multimorbidity: having ≥ 3 medical conditions (risks). 

Temporal estimates of case-fatality rate for COVID-19 outbreaks in Canada and the United States

COVID-19 and the impact of social determinants of health. The Lancet

Revisiting the healthy immigrant effect with diabetes risk in Canada: Why race/ethnicity matters

Why inequality could spread COVID-19. The Lancet. Public Health

Structural racism and health inequities in the USA: Evidence and interventions. The Lancet

The COVID-19 pandemic and health inequalities

Socioeconomic inequalities in childhood and adolescent body-mass index, weight, and height from 1953 to 2015: An analysis of four longitudinal, observational, British birth cohort studies

Social conditions as fundamental causes of disease

Differences between women's and men's socioeconomic inequalities in health: Longitudinal analysis of the Canadian population

Social determinants of health inequalities

Insights into the 'healthy immigrant effect': Health status and health service use of immigrants to Canada

The socioeconomic determinants of cancer

Gradient of disability across the socioeconomic spectrum in the united states

Income inequalities in multimorbidity prevalence in ontario, canada: A decomposition analysis of linked survey and health administrative data

The impact of social disadvantage in moderate-to-severe chronic kidney disease: An equityfocused systematic review

Chronic conditions and the healthy immigrant effect: Evidence from canadian immigrants

Social determinants of health: Future directions for health disparities research

Factors associated with hospital admission and critical illness among 5279 people with coronavirus disease

Controlling disease and creating disparities: A fundamental cause perspective

Social conditions as fundamental causes of health inequalities: Theory, evidence, and policy implications

Variation in health services utilization among ethnic populations

Racial disparities in exposure, susceptibility, and access to health care in the US H1N1 influenza pandemic

Disparities in the population at risk of severe illness from COVID-19 by race/ethnicity and income

The canadian longitudinal study on aging (CLSA)*

Greater risk of severe COVID-19 in black, asian and minority ethnic populations is not explained by cardiometabolic, socioeconomic or behavioural factors, or by 25(OH)-vitamin D status: Study of 1326 cases from the UK biobank

Equally inequitable? A cross-national comparative study of racial health inequalities in the united states and canada

Barriers to addressing the social determinants of health: Insights from the canadian experience

The prevalence of multimorbidity and associations with lifestyle factors among middle-aged canadians: An analysis of canadian longitudinal study on aging data

COVID-19 and racial/ethnic disparities in health risk, employment and household composition: Study examines potential explanations for racialethnic disparities in COVID-19 hospitalizations and mortality

Socioeconomic differentials in peripheral biology: Cumulative allostatic load

Vulnerability and unmet health care needs

Associations between race, discrimination and risk for chronic disease in a population-based sample from canada

Using social and behavioural science to support COVID-19 pandemic response

Are immigrants healthier than native born Canadians? A systematic review of the healthy immigrant effect in Canada

Racialized identity and health in canada: Results from a nationally representative survey

Black-White health inequalities in Canada

More than culture: structural racism, intersectionality theory, and immigrant health

Combating COVID-19: Health equity matters

Chronic kidney disease. The Lancet

Closing the gap in a generation: Health equity through action on the social determinants of health

A c c e p t e d

M a n u s c r i p t 35 Figure 2 Weighted prevalence and adjusted odds ratios of multiple medical conditions as risk factors of severe COVID-19 illness by race-nativity, income, education and cumulative profile (n=29,748)