A selection from Stockholm University publication database

• Inequalities in COVID-19 severe morbidity and mortality by country of birth in Sweden

  2023. Mikael Rostila (et al.). Nature Communications 14 (1)

  Article

  Migrants have been more affected by the COVID-19 pandemic. Whether this has varied over the course of the pandemic remains unknown. We examined how inequalities in intensive care unit (ICU) admission and death related to COVID-19 by country of birth have evolved over the course of the pandemic, while considering the contribution of social conditions and vaccination uptake. A population-based cohort study was conducted including adults living in Sweden between March 1, 2020 and June 1, 2022 (n = 7,870,441). Poisson regressions found that migrants from Africa, Middle East, Asia and European countries without EU28/EEA, UK and Switzerland had higher risk of COVID-19 mortality and ICU admission than Swedish-born. High risks of COVID-19 ICU admission was also found in migrants from South America. Inequalities were generally reduced through subsequent waves of the pandemic. In many migrant groups socioeconomic status and living conditions contributed to the disparities while vaccination campaigns were decisive when such became available.

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• Differences in incidence, nature of symptoms, and duration of long COVID among hospitalised migrant and non-migrant patients in the Netherlands: a retrospective cohort study

  2023. Felix Patience Chilunga (et al.). The Lancet Regional Health - Europe 29

  Article

  Background Comprehensive data on long COVID across ethnic and migrant groups are lacking. We investigated incidence, nature of symptoms, clinical predictors, and duration of long COVID among COVID-19 hospitalised patients in the Netherlands by migration background (Dutch, Turkish, Moroccan, and Surinamese origin, Others).

  Methods We used COVID-19 admissions and follow up data (January 2021–July 2022) from Amsterdam University Medical Centers. We calculated long COVID incidence proportions per NICE guidelines by migration background and assessed for clinical predictors via robust Poisson regressions. We then examined associations between migration background and long COVID using robust Poisson regressions and adjusted for derived clinical predictors, and other biologically relevant factors. We also assessed long COVID symptom persistence at one-yearpost-discharge.

  Findings 1886 patients were included. 483 patients had long COVID (26%, 95% CI 24–28%) at 12 weeks post-discharge.

  Symptoms like dizziness, joint pain, insomnia, and headache varied by migration background. Clinical predictors of long COVID were female sex, hospital admission duration, intensive care unit admission, and receiving oxygen, or corticosteroid therapy. Long COVID risk was higher among patients with migration background than Dutch origin patients after adjustments for derived clinical predictors, age, smoking, vaccination status, comorbidities and remdesivir treatment. Only 14% of long COVID symptoms persisted at one-year post-discharge.

  Interpretation There are significant differences in occurrence, nature of symptoms, and duration of long COVID by migration background. Studies assessing the spectrum of functional limitation and access to post-COVID healthcare are needed to help plan for appropriate and accessible health care interventions.

  Funding The Amsterdam UMC COVID-19 biobank is supported by the Amsterdam UMC Corona Research Fund and the Talud Foundation (Stichting Talud). The current analyses were supported by the Novo Nordisk Foundation[NNF21OC0067528]

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• Microsimulation as a flexible tool to evaluate policies and their impact on socioeconomic inequalities in health

  2023. Daniel Kopasker (et al.). The Lancet Regional Health - Europe 34

  Article

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• Substance use disorder and suicide-related behaviour around dates of parental death and its anniversaries: a register-based cohort study

  2022. Ayako Hiyoshi (et al.). The Lancet Public Health 7 (8), e683-e693

  Article

  Summary

  Background Parental death and its anniversaries, including anticipation of these dates, might cause distress andincrease the risk of substance use disorder and suicide-related behaviour in bereaved adolescents and young adults.We examined whether the risk of substance use disorder and suicide-related behaviour increases around the date ofparental death and subsequent anniversaries.

  Methods Using Swedish national registers, we conducted a cohort study of individuals aged 12–24 years. We includedindividuals aged 12–24 years between Jan 1, 2001, and Dec 31, 2014, whose parents were alive at entry (n=1 858 327)and followed up with them until the end of age 24 years. We excluded individuals with a half-sibling, a history ofemigration, a previous record of the outcome events, a parental death before study entry, two parental deaths on thesame day during the follow-up, or missing data for relevant variables. Follow-up ended on the day of an outcomeevent or on Dec 31, 2014; at age 25 years, emigration, or death; or a year before the second parental death. We studiedsubstance use disorder and suicide-related behaviour outcomes separately and included non-fatal and fatal events inboth outcomes. We used Cox regression to estimate hazard ratios (HRs), controlling for baseline psychiatric,demographic, and socioeconomic characteristics. Parental death was modelled as a time-varying exposure over72 monthly periods, starting from 1 year before the parental death to the fifth year and later after the death.Unmeasured confounding was also addressed in within-individual comparisons using a case-crossover design.

  Findings During follow-up (median 7·5 [IQR 4·3–10·6] years), there were 42 854 substance use disorder events, witha crude rate of 3·1 per 1000 person-years. For suicide-related behaviour, there were 19 827 events, with a crude rate of1·4 per 1000 person-years. Most of the events studied were non-fatal. In the month of parental death, the HR forsubstance use disorder risk was 1·89 (95% CI 1·07–3·33) among male participants, and, for suicide-related behaviour,was 3·76 (1·79–7·89) among male participants and 2·90 (1·61–5·24) among female participants. In male participants,there was an increased risk around the first anniversary (substance use disorder: HR 2·64 [95% CI 1·56–4·46] duringthe anniversary month; 2·21 [1·25–3 ·89] for the subsequent month; and for suicide-related behaviour: 3·18[1·32–7·66] for the subsequent month). Among female participants, an increased risk of substance use disorderrecurred around every year consistently in the month before the anniversary of the death and there was an increasedrisk for suicide-related behaviour in the months of the first and second anniversaries.

  Interpretation Although effect sizes were large in this cohort study, the number of individuals who had the outcomeswas small. Nevertheless, adolescents and young adults, especially women and girls, who had the death of a parentshowed increased risk of substance use disorder and suicide-related behaviour around the first few death anniversaries.Adolescents and young adults, especially women and girls, who had the death of a parent could benefit from preventivemeasures to reduce distress around the first few years of death anniversaries

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• School Outcomes Among Children Following Death of a Parent

  2022. Can Liu (et al.). JAMA Network Open 5 (4)

  Article

  Importance  To better support children with the experience of parental death, it is crucial to understand whether parental death increases the risk of adverse school outcomes.

  Objectives  To examine whether parental death is associated with poorer school outcomes independent of factors unique to the family, and whether children of certain ages are particularly vulnerable to parental death.

  Design, Setting, and Participants  This population-based sibling cohort study used Swedish national register-based longitudinal data with linkage between family members. Register data were collected from January 1, 1990, to December 31, 2016. Data analyses were performed on July 14, 2021. The participants were all children born between 1991 and 2000 who lived in Sweden before turning age 17 years (N = 908 064).

  Exposure  Parental death before finishing compulsory school.

  Main Outcomes and Measures  Mean school grades (year-specific z scores) and ineligibility for upper secondary education on finishing compulsory school at age 15 to 16 years. Population-based cohort analyses were conducted to examine the association between parental death and school outcomes using conventional linear and Poisson regression models, after adjustment for demographic and parental socioeconomic and health indicators measured before childbirth. Second, using fixed-effect linear and Poisson regression models, children who experienced parental death before finishing compulsory school were compared with their siblings who experienced the death after. Third, the study explored the age-specific associations between parental death and school outcomes.

  Results  In the conventional population-based analyses, bereaved children (N = 22 634; 11 553 boys [51.0%]; 11 081 girls [49.0%]; mean [SD] age, 21.0 [2.8] years) had lower mean school grade z scores (adjusted β coefficient, −0.19; 95% CI, −0.21 to −0.18; P < .001) and a higher risk of ineligibility for upper secondary education than the nonbereaved children (adjusted risk ratio, 1.36; 95% CI, 1.32-1.41; P < .001). Within-sibling comparisons using fixed-effects models showed that experiencing parental death before finishing compulsory school was associated with lower mean school grade z scores (−0.06; 95% CI, −0.10 to −0.01; P = .02) but not with ineligibility for upper secondary education (adjusted risk ratio, 1.07; 95% CI, 0.93-1.23; P = .34). Independent of birth order, losing a parent at a younger age was associated with lower grades within a family.

  Conclusions and Relevance  In this cohort study, childhood parental death was associated with lower school grades after adjustment for familial confounders shared between siblings. Children who lost a parent may benefit from additional educational support that could reduce the risk of adverse socioeconomic trajectories later in life.

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• Disparities in Coronavirus Disease 2019 Mortality by Country of Birth in Stockholm, Sweden

  2021. Mikael Rostila (et al.). American Journal of Epidemiology 190 (8), 1510-1518

  Article

  Preliminary evidence points to higher morbidity and mortality from coronavirus disease 2019 (COVID-19) in certain racial and ethnic groups, but population-based studies using microlevel data are lacking so far. We used register-based cohort data including all adults living in Stockholm, Sweden, between January 31, 2020 (the date of the first confirmed case of COVID-19) and May 4, 2020 (n = 1,778,670) to conduct Poisson regression analyses with region/country of birth as the exposure and underlying cause of COVID-19 death as the outcome, estimating relative risks and 95% confidence intervals. Migrants from Middle Eastern countries (relative risk (RR) = 3.2, 95% confidence interval (CI): 2.6, 3.8), Africa (RR = 3.0, 95% CI: 2.2, 4.3), and non-Sweden Nordic countries (RR = 1.5, 95% CI: 1.2, 1.8) had higher mortality from COVID-19 than persons born in Sweden. Especially high mortality risks from COVID-19 were found among persons born in Somalia, Lebanon, Syria, Turkey, Iran, and Iraq. Socioeconomic status, number of working-age household members, and neighborhood population density attenuated up to half of the increased COVID-19 mortality risks among the foreign-born. Disadvantaged socioeconomic and living conditions may increase infection rates in migrants and contribute to their higher risk of COVID-19 mortality.

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• Parental death in childhood and pathways to increased mortality across the life course in Stockholm, Sweden

  2021. Ayako Hiyoshi (et al.). PLoS Medicine 18 (3)

  Article

  Background

  Previous studies have shown that the experience of parental death during childhood is associated with increased mortality risk. However, few studies have examined potential pathways that may explain these findings. The aim of this study is to examine whether familial and behavioural factors during adolescence and socioeconomic disadvantages in early adulthood mediate the association between loss of a parent at age 0 to 12 and all-cause mortality by the age of 63.

  Methods and findings

  A cohort study was conducted using data from the Stockholm Birth Cohort Multigenerational Study for 12,615 children born in 1953, with information covering 1953 to 2016. Familial and behavioural factors at age 13 to 19 included psychiatric and alcohol problems in the surviving parent, receipt of social assistance, and delinquent behaviour in the offspring. Socioeconomic disadvantage in early adulthood included educational attainment, occupational social class, and income at age 27 to 37. We used Cox proportional hazard regression models, combined with a multimediator analysis, to separate direct and indirect effects of parental death on all-cause mortality.

  Among the 12,582 offspring in the study (men 51%; women 49%), about 3% experienced the death of a parent in childhood. During follow-up from the age of 38 to 63, there were 935 deaths among offspring. Parental death was associated with an elevated risk of mortality after adjusting for demographic and household socioeconomic characteristics at birth (hazard ratio [HR]: 1.52 [95% confidence interval: 1.10 to 2.08, p-value = 0.010]). Delinquent behaviour in adolescence and income during early adulthood were the most influential mediators, and the indirect associations through these variables were HR 1.03 (1.00 to 1.06, 0.029) and HR 1.04 (1.01 to 1.07, 0.029), respectively. After accounting for these indirect paths, the direct path was attenuated to HR 1.35 (0.98 to 1.85, 0.066). The limitations of the study include that the associations may be partly due to genetic, social, and behavioural residual confounding, that statistical power was low in some of the subgroup analyses, and that there might be other relevant paths that were not investigated in the present study.

  Conclusions

  Our findings from this cohort study suggest that childhood parental death is associated with increased mortality and that the association was mediated through a chain of disadvantages over the life course including delinquency in adolescence and lower income during early adulthood. Professionals working with bereaved children should take the higher mortality risk in bereaved offspring into account and consider its lifelong consequences. When planning and providing support to bereaved children, it may be particularly important to be aware of their increased susceptibility to delinquency and socioeconomic vulnerability that eventually lead to higher mortality.

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• Inequalities in all-cause and cause-specific mortality across the life course by wealth and income in Sweden

  2020. S Vittal Katikireddi (et al.). International Journal of Epidemiology 49 (3), 917-925

  Article

  Background: Wealth inequalities are increasing in many countries, but their relationship to health is little studied. We investigated the association between individual wealth and mortality across the adult life course in Sweden.

  Methods: We studied the Swedish adult population using national registers. The amount of wealth tax paid in 1990 was the main exposure of interest and the cohort was followed up for 18 years. Relative indices of inequality (RII) summarize health inequalities across a population and were calculated for all-cause and cause-specific mortality for six different age groups, stratified by sex, using Poisson regression. Mortality inequalities by wealth were contrasted with those assessed by individual and household income. Attenuation by four other measures of socio-economic position and other covariates was investigated.

  Results: Large inequalities in mortality by wealth were observed and their association with mortality remained more stable across the adult life course than inequalities by income-based measures. Men experienced greater inequalities across all ages (e.g. the RII for wealth was 2.58 [95% confidence interval (CI) 2.54-2.63) in men aged 55-64 years compared with 2.29 (95% CI 2.24-2.34) for women aged 55-64 years), except among the over 85s. Adjustment for covariates, including four other measures of socio-economic position, led to only modest reductions in the association between wealth and mortality.

  Conclusions: Wealth is strongly associated with mortality throughout the adult life course, including early adulthood. Income redistribution may be insufficient to narrow health inequalities-addressing the increasingly unequal distribution of wealth in high-income countries should be considered.

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• Residential context and COVID-19 mortality among adults aged 70 years and older in Stockholm

  2020. Maria Brandén (et al.). The Lancet. Healthy Longevity 1 (2), e80-e88

  Article

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• Effects of non-health-targeted policies on migrant health

  2019. Sol Juárez (et al.). The Lancet Global Health

  Article

  Background: Government policies can strongly influence migrants' health. Using a Health in All Policies approach, we systematically reviewed evidence on the impact of public policies outside of the health-care system on migrant health. Methods: We searched the PubMed, Embase, and Web of Science databases from Jan 1, 2000, to Sept 1, 2017, for quantitative studies comparing the health effects of non-health-targeted public policies on migrants with those on a relevant comparison population. We searched for articles written in English, Swedish, Danish, Norwegian, Finnish, French, Spanish, or Portuguese. Qualitative studies and grey literature were excluded. We evaluated policy effects by migration stage (entry, integration, and exit) and by health outcome using narrative synthesis (all included studies) and random-effects meta-analysis (all studies whose results were amenable to statistical pooling). We summarised meta-analysis outcomes as standardised mean difference (SMD, 95% CI) or odds ratio (OR, 95% CI). To assess certainty, we created tables containing a summary of the findings according to the Grading of Recommendations Assessment, Development, and Evaluation. Our study was registered with PROSPERO, number CRD42017076104. Findings: We identified 43 243 potentially eligible records. 46 articles were narratively synthesised and 19 contributed to the meta-analysis. All studies were published in high-income countries and examined policies of entry (nine articles) and integration (37 articles). Restrictive entry policies (eg, temporary visa status, detention) were associated with poor mental health (SMD 0·44, 95% CI 0·13–0·75; I²=92·1%). In the integration phase, restrictive policies in general, and specifically regarding welfare eligibility and documentation requirements, were found to increase odds of poor selfrated health (OR 1·67, 95% CI 1·35–1·98; I²=82·0%) and mortality (1·38, 1·10–1·65; I²=98·9%). Restricted eligibility for welfare support decreased the odds of general health-care service use (0·92, 0·85–0·98; I²=0·0%), but did not reduce public health insurance coverage (0·89, 0·71–1·07; I²=99·4%), nor markedly affect proportions of people without health insurance (1·06, 0·90–1·21; I²=54·9%). Interpretation: Restrictive entry and integration policies are linked to poor migrant health outcomes in high-income countries. Efforts to improve the health of migrants would benefit from adopting a Health in All Policies perspective.

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• Experience of Sibling Death in Childhood and Risk of Death in Adulthood

  2017. Mikael Rostila (et al.). American Journal of Epidemiology 185 (12), 1247-1254

  Article

  Although there is some evidence of an association between loss of a sibling in adulthood and subsequentmortality, there have been no previous studies in which investigators have examined whether the death of a sibling in childhood is associated with adult mortality using total population data. Data on a national cohort born in Sweden in 1973-1982 (n = 717,723) were prospectively collected from the Cause of Death Register until 2013 (i.e., from the ages of 18 years to 31-40 years). Cox proportional hazards models were used to analyze the association between sibling loss during childhood and death in young adulthood. After adjustment for sociodemographic confounders and parental psychosocial covariates, the hazard ratio for all-cause mortality in bereaved siblings versus nonbereaved siblings was 1.39 (95% confidence interval: 1.14, 1.69). Risks were more pronounced for those who lost a noninfant sibling (i.e., > 1 year of age) (hazard ratio = 1.53, 95% confidence interval: 1.18, 1.95) and those who lost a sibling in adolescence (i.e., between the ages of 12 and 18 years) (hazard ratio = 1.71, 95% confidence interval: 1.24, 2.35). Excess mortality risk was found for concordant causes of death (i. e., siblings dying from the same causes) but not for discordant causes.

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• Birth Order and Suicide in Adulthood

  2014. Mikael Rostila, Jan Saarela, Ichiro Kawachi. American Journal of Epidemiology 179 (12), 1450-1457

  Article

  Each year, almost 1 million people die from suicide, which is among the leading causes of death in young people. We studied how birth order was associated with suicide and other main causes of death. A follow-up study based on the Swedish population register was conducted for sibling groups born from 1932 to 1980 who were observed during the period 1981-2002. Focus was on the within-family variation in suicide risk, meaning that we studied sibling groups that consisted of 2 or more children in which at least 1 died from suicide. These family-fixed effects analyses revealed that each increase in birth order was related to an 18% higher suicide risk (95% confidence interval (CI): 1.14, 1.23, P = 0.000). The association was slightly lower among sibling groups born in 1932-1955 (hazard ratio = 1.13, 95% CI: 1.06, 1.21, P = 0.000) than among those born in 1967-1980 (hazard ratio = 1.24, 95% CI: 0.97, 1.57, P = 0.080). Further analyses suggested that the association between birth order and suicide was only modestly influenced by sex, birth spacing, size of the sibling group, own socioeconomic position, own marital status, and socioeconomic rank within the sibling group. Causes of death other than suicide and other external causes were not associated with birth order.

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• Mortality differentials by immigrant groups in Sweden

  2014. Mikael Rostila, Johan Fritzell. American Journal of Public Health 104 (4), 686-695

  Article

  Objectives. We studied mortality differentials between specific groups of foreign-born immigrants in Sweden and whether socioeconomic position (SEP) could account for such differences. Methods. We conducted a follow-up study of 1 997 666 men and 1 964 965 women ages 30 to 65 years based on data from national Swedish total population registers. We examined mortality risks in the 12 largest immigrant groups in Sweden between 1998 and 2006 using Cox regression. We also investigated deaths from all causes, circulatory disease, neoplasms, and external causes. Results. We found higher all-cause mortality among many immigrant categories, although some groups had lower mortality. When studying cause-specific mortality, we found the largest differentials in deaths from circulatory disease, whereas disparities in mortality from neoplasms were smaller. SEP, especially income and occupational class, accounted for most of the mortality differentials by country of birth. Conclusions. Our findings stressed that different aspects of SEP were not interchangeable in relation to immigrant health. Although policies aimed at improving immigrants' socioeconomic conditions might be beneficial for health and longevity, our findings indicated that such policies might have varying effects depending on the specific country of origin and cause of death.

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• Social capital and health inequality in European welfare states

  2013. Mikael Rostila.

  Book

  This book sets out unique findings on whether social capital influences health and health inequalities in European welfare states. Drawing on cross-national data from the European Social Survey (ESS) as well as Swedish national survey data and registers, the book develops a new theoretical definition of social capital that guides the books empirical studies. The findings suggest that welfare state generosity is a decisive factor for social capital and that social capital is of significance for health inequalities both between and within European welfare states. The book also discusses the potential dark sides of social capital and examines evidence of circumstances in which social capital has negative health externalities.

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• Den orättvisa hälsan

  2012. Mikael Rostila, Susanna Toivanen.

  Book

  I vilken utsträckning är hälsan ojämlikt fördelad i Sverige och i övriga världen? Varför lever människor med högre social position längre än andra? Hur kan hälsan fördelas mer rättvist?Dessa är några av de frågor som denna unika svenska bok önskar besvara och klargöra. Boken handlar om hur människors position i samhällets hierarkiska strukturer är nära förknippad med systematiska skillnader i hälsa. Var vi råkar födas i världen, men även den sociala position vi har i ett givet samhälle, har stor betydelse för vår hälsa och livslängd. Trots att en jämlik hälsa borde vara en mänsklig rättighet har hälsans ojämlika fördelning ofta stått långt ned på den politiska dagordningen.

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• The Forgotten Griever

  2012. Mikael Rostila, Jan Saarela, Ichiro Kawachi. American Journal of Epidemiology 176 (4), 338-346

  Article

  Previous findings have suggested that the loss of a family member is associated with mortality among bereaved family members. The least-studied familial relationship in the bereavement literature is that of siblings, although loss of a sibling may also involve health consequences. The authors conducted a follow-up study based on data from the Swedish total population register, covering the period 1981–2002. Using Cox regression, mortality risk ratios for bereaved and nonbereaved persons aged 18–69 years were estimated. All-cause mortality and cause-specific mortality (unnatural causes, natural causes, cardiovascular disease, cancer, suicide, accidents, and all other causes) were examined. In men, the mortality risk for bereaved persons versus nonbereaved persons was 1.26 (95% confidence interval: 1.22, 1.30), and in women it was 1.33 (95% confidence interval: 1.28, 1.39). An elevated mortality risk associated with a sibling's death was found in all age groups studied, but the association was generally stronger at younger ages and could be observed predominantly after more than 1 year of follow-up. There was also an increased mortality risk if the sibling had died from a discordant main cause, which may strengthen the possibility that the association observed is not due to confounding alone.

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• The two facets of social capital

  2011. Mikael Rostila. Journal for the Theory of Social Behaviour 41 (3), 308-326

  Article

  The emergence of the two facets of social capital, the individual and the collective, has contributed to much of the confusion in the field of social capital. The overall objective of this article is to elaborate on a theoretical model aiming at clarifying some bridges between the facets and dimensions of social capital previously suggested in the literature. Initially, the article shortly presents and discusses some important definitions of social capital. Furthermore, limitations and shortcomings of previous definitions are discussed. Moreover, a theoretical model is elaborated on suggesting that social capital comprises social resources that evolve in accessible social networks or social structures characterized by mutual trust. This model also emphasises some of the potential dark sides of social capital. The presented definition does not definitively address the theoretical uncertainties in the field; however, it suggests that a resource-oriented notion of social capital could be useful in bridging the facets of social capital.

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• Risk of long COVID and associated symptoms after acute SARS-COV-2 infection in ethnic minorities: a nationwide register-linked cohort study in Denmark

  2024. George Frederick Mkoma (et al.). PLoS Medicine 21 (2), e1004280

  Article

  Background: Ethnic minorities living in high-income countries have been disproportionately affected by Coronavirus Disease 2019 (COVID-19) in terms of infection rates, hospitalisations, and deaths; however, less is known about long COVID in these populations. Our aim was to examine the risk of long COVID and associated symptoms among ethnic minorities.

  Methods and findings: We used nationwide register-based cohort data on individuals diagnosed with COVID-19 aged ≥18 years (n = 2,287,175) between January 2020 and August 2022 in Denmark. We calculated the risk of long COVID diagnosis and long COVID symptoms among ethnic minorities compared with native Danes using multivariable Cox proportional hazard regression and logistic regression, respectively.

  Among individuals who were first time diagnosed with COVID-19 during the study period, 39,876 (1.7%) were hospitalised and 2,247,299 (98.3%) were nonhospitalised individuals. Of the diagnosed COVID-19 cases, 1,952,021 (85.3%) were native Danes and 335,154 (14.7%) were ethnic minorities. After adjustment for age, sex, civil status, education, family income, and Charlson comorbidity index, ethnic minorities from North Africa (adjusted hazard ratio [aHR] 1.41, 95% confidence interval [CI] [1.12,1.79], p = 0.003), Middle East (aHR 1.38, 95% CI [1.24,1.55], p < 0.001), Eastern Europe (aHR 1.35, 95% CI [1.22,1.49], p < 0.001), and Asia (aHR 1.23, 95% CI [1.09,1.40], p = 0.001) had significantly greater risk of long COVID diagnosis than native Danes. In the analysis by largest countries of origin, the greater risks of long COVID diagnosis were found in people of Iraqi origin (aHR 1.56, 95% CI [1.30,1.88], p < 0.001), people of Turkish origin (aHR 1.42, 95% CI [1.24,1.63], p < 0.001), and people of Somali origin (aHR 1.42, 95% CI [1.07,1.91], p = 0.016). A significant factor associated with an increased risk of long COVID diagnosis was COVID-19 hospitalisation. The risk of long COVID diagnosis among ethnic minorities was more pronounced between January 2020 and June 2021. Furthermore, the odds of reporting cardiopulmonary symptoms (including dyspnoea, cough, and chest pain) and any long COVID symptoms were higher among people of North African, Middle Eastern, Eastern European, and Asian origins than among native Danes in both unadjusted and adjusted models. Despite including the nationwide sample of individuals diagnosed with COVID-19, the precision of our estimates on long COVID was limited to the sample of patients with symptoms who had contacted the hospital.

  Conclusions: Belonging to an ethnic minority group was significantly associated with an increased risk of long COVID, indicating the need to better understand long COVID drivers and address care and treatment strategies in these populations.

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