Background

In recent decades, Sweden has become an increasingly diverse society by origin, but one in which residential segregation by migrant background has also increased. This study examines how different aspects of migrant residential segregation are associated with all-cause mortality among native-born and migrant populations.

Methods Using Swedish population-based registers, this longitudinal open cohort study assessed associations between four local level indices of migrant residential segregation and all-cause mortality among adult migrant and native-born residents of Sweden's three largest metropolitan areas (Stockholm, Gothenburg, and Malmö) between 2004 and 2016. Multilevel Poisson regression models, adjusted for individual-level sociodemographic and socioeconomic factors as well as area-level socioeconomic conditions, were used to estimate associations between these indices and all-cause mortality.

Results

Moderate decreased mortality risks were observed among migrants in residential areas with higher levels of migrant density, isolation, and exposure in fully adjusted models. However, isolation and exposure effects could not be distinguished due to a high degree of correlation between the isolation and exposure measures. In fully adjusted models mortality gradients were largely unobserved among native-born individuals in relation to migrant residential segregation. The evenness dimension of segregation showed limited relevance for mortality risk in both groups.

Conclusions

This study provides evidence that higher migrant density is associated with lower mortality risks among migrants, suggesting that residential areas with higher proportions of migrants may offer health benefits for migrants. These findings highlight the importance of residential contexts in shaping migrant health outcomes.

Conjugal ties may contribute to a convergence of health behaviours between migrants and natives, but the association between intermarriage and health outcomes remains understudied. We investigated mortality patterns among Finnish migrants in Sweden according to the spouse’s country of birth and compared these patterns with those observed in the native populations of both Sweden and Finland. Leveraging register data from Sweden and Finland, we identified all married Finnish migrants aged 40–64 and their spouses in Sweden in 1999 and corresponding reference groups in both countries. We used a combination of direct matching and inverse probability weighting to adjust for sociodemographic differences between the groups. We followed individuals for all-cause, alcohol-related, smoking-related, and cardiovascular disease (CVD) mortality during 2000–17. Accounting for sociodemographic characteristics, Finnish migrant men married to Swedish-born as opposed to Finnish-born spouses showed lower all-cause [incidence rate ratio (IRR) 0.94, 95% confidence interval (CI) 0.90–0.98], and CVD mortality (IRR 0.88, 95% CI 0.81–0.95), levels more akin to native Swedes. Migrant women with Swedish-born spouses instead had higher smoking-related mortality (IRR 1.41, 95% CI 1.24–1.61) than those married to Finnish-born spouses, mirroring the higher smoking-related mortality of native Swedish women. Individual-level regression analysis on migrants further indicated lower alcohol-related mortality for intermarried men, adjusted for duration of marriage (IRR 0.74, 95% CI 0.56–0.98). These findings suggest that intermarriage with a native spouse can facilitate the convergence of health behaviours and behaviour-related mortality between migrants and natives.

Background  Many studies have found more severe COVID-19 outcomes in migrants and ethnic minorities throughout the COVID-19 pandemic, while recent evidence also suggests higher risk of longer-term consequences. We studied the risk of a long COVID diagnosis among adult residents in Sweden, dependent on country of birth and accounting for known risk factors for long COVID.

Methods  We used linked Swedish administrative registers between March 1, 2020 and April 1, 2023, to estimate the risk of a long COVID diagnosis in the adult population that had a confirmed COVID-19 infection. Poisson regressions were used to calculate incidence rate ratios (IRR) of long COVID by country/region of birth. The contribution of sex, preexisting health status, disease severity, vaccination status, and socioeconomic factors to differences in long COVID diagnosis by country/region of birth were further investigated.

Results  Of the 1,869,188 persons diagnosed with COVID-19 that were included, 7539 had received a long COVID diagnosis. Compared with residents born in Sweden, we found higher risks of long COVID among migrants from East Europe (IRR: 1.44 CI: 1.29–1.60), Finland (IRR: 1.36 CI: 1.15–1.61), South Asia (IRR: 1.28 CI: 1.03–1.59), Other Asia (IRR: 1.35 CI: 1.13–1.62), Other Africa (IRR: 1.48 CI: 1.17–1.87), and the Middle East (IRR: 1.43 CI: 1.27–1.63) in models adjusted for age and sex. We discovered that disease severity, i.e., whether the person was hospitalized (IRR: 18.6 CI: 17.3–20.0) or treated in an intensive care unit (IRR: 120.5 CI: 111.7–129.8), primarily contributed to the higher risk of long COVID found in migrants while the contribution of vaccinations and social conditions were moderate. Preexisting health problems did not contribute to the increased risk of long COVID in migrants.

Conclusions  The greater exposure and impact of the COVID-19 virus among migrants also affected longer-term consequences. Disease severity was the most important risk factor for long COVID in migrants. The findings emphasize the need for targeted health interventions for migrant communities during an infectious disease pandemic, such as strategic vaccination campaigns and extending social insurance schemes, focusing on reducing disease severity to mitigate the longer-term health consequences of an infection.

Objectives: Polycystic ovary syndrome (PCOS) is an endocrine disorder in women of fertile age which may also affect the labor market attachment. We investigated labor market attachment trajectories among working age women diagnosed with PCOS.

Methods: A cohort of 157,356 women born in 1975–1977 were followed annually between the ages of 30 and 39, using data from Swedish administrative registers. Multinomial logistic regression was employed to assess associations between being diagnosed with PCOS (after the age of 15) and belonging to the identified clusters of labor market attachment trajectories.

Results: Women with PCOS spent less time in employment and were more dependent on sickness benefits during the follow-up time than those without PCOS. Five labor market attachment clusters were identified: stable employment, education into employment, labor market exclusion, continuously unstable position, long-term sickness. Compared to being in the stable employment cluster, women diagnosed with PCOS were more likely to experience long-term sickness [RRR (relative risk ratio): 1.97 (CI: 1.90–2.05)], and education into employment [RRR: 1.11 (CI: 1.07–1.15)].

Conclusion: PCOS can lead to disadvantaged labor market outcomes. Better strategies are needed to prevent economic exclusion among women diagnosed with PCOS.

Background: Low socioeconomic status has been demonstrated as a risk factor for COVID-19 severity and mortality. However, whether socioeconomic disparities also influence the risk of long COVID diagnosis among ethnic minorities compared to the native majority population remains unclear. Methods: We conducted a nationwide register-based cohort study in Denmark, including individuals with a first-time COVID-19 diagnosis between January 2020 and August 2022. The risk of long COVID diagnosis among ethnic groups (defined by country of birth) was compared according to socioeconomic status. Results: Among 2 287 175 COVID-19 cases, 4579 were diagnosed with long COVID. The risk of long COVID diagnosis did not significantly differ by income or educational attainment for most ethnic groups. However, among low-income individuals, migrants had a higher risk of long COVID than native Danes, particularly Eastern Europeans (HRadjusted 1.45, 95 % CI [1.25,1.70], p < 0.001), Southeast Asians (HRadjusted 2.08, 95 % CI [1.32,3.28], p = 0.002), Middle Easterners (HRadjusted 1.65, 95 % CI [1.31,2.07], p < 0.001), and North Africans (HRadjusted 1.68, 95 % CI [1.24,2.27], p < 0.001). Additionally, migrant workers (Eastern European, Middle Eastern, and South Asian) in occupational sectors such as “economy, business, and administration”, “operator, driver and transportation service”, “sales and customer service”, “general office and secretarial service” and “education” had a higher long COVID risk than native Danish workers in the same workplaces. Implications: These findings highlight the need to address ethnic disparities in long COVID, particularly among migrants with low income. Workplace interventions and policies targeting work-related vulnerabilities could help reduce the disproportionate burden of long COVID among migrant workers.

Numerous studies have reported lower overall cancer mortality rates among immigrants compared to native populations. However, limited information exists regarding cancer mortality among immigrants based on specific birth countries and cancer types. We used population-based registries and followed 10 million individuals aged 20 years or older in Sweden between 1992 and 2016. The Cox proportional hazard model was used to explore the disparities in cancer mortality by country of birth and cancer type, stratified by gender. Age-standardized mortality rates were also computed using the world standard population. Hazard ratio (HR) of all-site cancer was slightly lower among immigrants (males: HRm = 0.97: 95% confidence interval: 0.95, 0.98; females: HRf = 0.93: 0.91, 0.94) than Swedish-born population. However, the immigrants showed higher mortality for infection-related cancers, including liver (HRf = 1.10: 1.01, 1.19; HRm = 1.10: 1.02, 1.17), stomach (HRf = 1.39: 1.31, 1.49; HRm = 1.33: 1.26, 1.41) cancers, and tobacco-related cancers, including lung (HRm = 1.44: 1.40, 1.49), and laryngeal cancers (HRm = 1.47: 1.24, 1.75). The HR of mesothelioma was also significantly higher in immigrants (HRf = 1.44: 1.10, 1.90). Mortality from lung cancer was specifically higher in men from Nordic (HRm = 1.41: 1.27, 1.55) and non-Nordic Europe (HRm = 1.49: 1.43, 1.55) countries and lower in Asian (HRm = 0.78: 0.66, 0.93) and South American men (HRm = 0.70: 0.57, 0.87). In conclusion, there are large variations in cancer mortality by country of birth, and cancer type and require regular surveillance. Our detailed analyses lead to some novel findings such as excess mortality rate of mesothelioma and laryngeal cancers in Immigrants in Sweden. A targeted cancer prevention program among immigrants in Sweden is needed.

Background Polycystic ovary syndrome (PCOS) has previously been associated with several comorbidities that may have shared genetic, epigenetic, developmental or environmental origins. PCOS may be influenced by prenatal androgen excess, poor intrauterine or childhood environmental factors, childhood obesity and learned health risk behaviors. We analyzed the association between PCOS and several relevant comorbidities while adjusting for early-life biological and socioeconomic conditions, also investigating the extent to which the association is affected by familial risk factors.

Methods This total-population register-based cohort study included 333,999 full sisters, born between 1962 and 1980. PCOS and comorbidity diagnoses were measured at age 17-45 years through national hospital register data from 1997 to 2011, and complemented with information on the study subjects´ early-life and social characteristics. In the main analysis, sister fixed effects (FE) models were used to control for all time-invariant factors that are shared among sisters, thereby testing whether the association between PCOS and examined comorbidities is influenced by unobserved familial environmental, social or genetic factors.

Results Three thousand five hundred seventy women in the Sister sample were diagnosed with PCOS, of whom 14% had obesity, 8% had depression, 7% had anxiety and 4% experienced sleeping, sexual and eating disorders (SSE). Having PCOS increased the odds of obesity nearly 6-fold (adjusted OR (aOR): 5.9 [95% CI:5.4-6.5]). This association was attenuated in models accounting for unobserved characteristics shared between full sisters, but remained considerable in size (Sister FE: aOR: 4.5 [95% CI: 3.6-5.6]). For depression (Sister FE: aOR: 1.4 [95% CI: 1.2-1.8]) and anxiety (Sister FE: aOR: 1.5 [95% CI: 1.2-1.8), there was a small decrease in the aORs when controlling for factors shared between sisters. Being diagnosed with SSE disorders yielded a 2.4 aOR (95% CI:2.0-2.6) when controlling for a comprehensive set of individual-level confounders, which only decreased slightly when controlling for factors at the family level such as shared genes or parenting style. Accounting for differences between sisters in observed early-life circumstances influenced the estimated associations marginally.

Conclusion Having been diagnosed with PCOS is associated with a markedly increased risk of obesity and sleeping, sexual and eating disorders, also after accounting for factors shared between sisters and early-life conditions.

Background: Explanations for the disproportional COVID-19 burden among immigrants relative to host-country natives include differential exposure to the virus and susceptibility due to poor health conditions. Prior to the pandemic, immigrants displayed deteriorating health with duration of residence that may be associated with increased susceptibility over time. The aim of this study was to compare immigrant–native COVID-19 mortality by immigrants’ duration of residence to examine the role of differential susceptibility. Methods: A population-based cohort study was conducted with individuals between 18 and 100 years old registered in Sweden between 1 January 2015 and 15 June 2022. Cox regression models were run to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). Results: Inequalities in COVID-19 mortality between immigrants and the Swedish-born population in the working-age group were concentrated among those of non-Western origins and from Finland with more than 15 years in Sweden, while for those of retirement age, these groups showed higher COVID-19 mortality HRs regardless of duration of residence. Both age groups of immigrants from Africa and the Middle East showed consistently higher COVID-19 mortality HRs. For the working-age population: Africa: HR<15: 2.46, 95%CI: 1.78, 3.38; HR≥15: 1.49, 95%CI: 1.01, 2.19; and from the Middle East: HR<15: 1.20, 95%CI: 0.90, 1.60; HR≥15: 1.65, 95%CI: 1.32, 2.05. For the retirement-age population: Africa: HR<15: 3.94, 95%CI: 2.85, 5.44; HR≥15: 1.66, 95%CI: 1.32, 2.09; Middle East: HR<15: 3.27, 95%CI: 2.70, 3.97; HR≥15: 2.12, 95%CI: 1.91, 2.34. Conclusions: Differential exposure, as opposed to differential susceptibility, likely accounted for the higher COVID-19 mortality observed among those origins who were disproportionately affected by the pandemic in Sweden.

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.

Higher rates of adverse birth outcomes have been consistently reported among children conceived via assisted reproductive technology (ART) compared with children conceived through natural conception. Higher rates of multiple births in ART pregnancies partially explain the increased risk. It remains unclear to what extent the remaining difference can be attributed to the reproductive technology or to factors related to infertility, which is associated with an elevated risk of poorer birth outcomes. Same-sex lesbian couples undergo ART treatments generally without experiencing infertility. To distinguish the effects of reproductive treatment and infertility, we compared birth outcomes in ART pregnancies among same-sex lesbian couples vs natural conceptions and ART pregnancies among heterosexual couples.

Methods: In Sweden, same-sex lesbian couples have been eligible to receive publicly funded ART treatments with donated sperm since 2005. This study included all births in Sweden from 2007 to 2018. Using pseudonymized personal identifiers, the Swedish National Quality Registry for Assisted Reproduction, which includes all ART treatments (in vitro fertilization [IVF], intracytoplasmic sperm injection [ICSI], and intrauterine insemination [IUI]), was linked to the medical birth register and the total population registers, which include information on birth outcomes and sociodemographic characteristics. We focused on first live births for ART and naturally conceived births because 97.3% of ART births among same-sex lesbian couples were first births. We analyzed 4 outcomes: birth weight (continuous), gestational age (continuous), low birth weight (binary, <2500 g), and preterm delivery (binary, <37 weeks of gestation). We estimated linear models on the continuous outcomes and linear probability models on the binary outcomes comparing ART-conceived births among same-sex lesbian couples (reference category) with ART births and naturally conceived births among heterosexual couples. For each outcome, we estimated unadjusted and adjusted (controlling for child sex, multiplicity, and maternal age at birth) models. We also estimated differences focusing on children conceived via IVF/ICSI because 99.4% of ART births among heterosexual couples were conceived via IVF/ICSI compared with 63.3% in same-sex couples, as same-sex couples often start treatments with IUI, which has a lower chance of success regardless of subfertility.

Analyses were conducted using R version 4.1.1 (R Foundation). Statistical significance was set at P < .05 (2-sided). This study was approved by the Regional Ethical Review Board of Stockholm. Informed consent was not required for pseudonymized data.

Results: During the study period, there were 868 ART births among same-sex lesbian couples, 23 488 ART births among heterosexual couples, and 456 898 naturally conceived births. ART-conceived births from same-sex and heterosexual couples showed a higher proportion of multiplicity (5.8% and 7.5%, respectively) than naturally conceived births (2.1%) (Table 1). Couples who conceived naturally had significantly lower birth weight and gestational age and similar risk of low birth weight and preterm delivery compared with same-sex couples who conceived via ART (Table 2). For example, birth weight was 3429.5 g in naturally conceived births vs 3460.2 g in same-sex ART births (adjusted difference, −76.2 g [95% CI, −113 to −39.3 g]; P < .001; low birth weight, 4.9% vs 6.7%, adjusted difference, 0.28 [95% CI, −1.11 to 1.66] percentage points; P = .70). Heterosexual couples who conceived via ART had statistically significantly lower birth weight and gestational age than same-sex couples (eg, birth weight: 3342.9 g vs 3460.2 g; adjusted difference, −97.4 g [95% CI, −134.8 to −59.9 g]; P < .001). Percentages of low birth weight and preterm birth were higher in ART conceptions among heterosexual couples vs same-sex couples but did not reach statistical significance (eg, low birth weight: 8.9% vs 6.7%; adjusted difference, 1.23 [95% CI, −0.17 to 2.65] percentage points; P = .09). The results were qualitatively similar when only considering IVF/ICSI-conceived children (Table 2).

Discussion: This study demonstrated that same-sex lesbian couples undergoing ART had more favorable or similar birth outcomes to heterosexual couples who conceived naturally or underwent ART to conceive, suggesting that infertility-related factors rather than reproductive treatments contribute to higher rates of adverse birth outcomes in ART pregnancies. Limitations of the study include that the presence of infertility factors was not directly assessed and the relatively small sample size of same-sex couples reduced the statistical power of the study, particularly in the binary outcomes analyses.