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Keywords:

  • mortality;
  • infections;
  • refugees;
  • immigration;
  • ethnic groups
  • mortalité;
  • infections;
  • réfugiés;
  • immigration;
  • groupes ethniques
  • mortalidad;
  • infecciones;
  • refugiados;
  • inmigración;
  • grupos étnicos

Summary

  1. Top of page
  2. Summary
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. References

Objectives  Refugees and immigrants are likely to be vulnerable to mortality from infectious diseases as a result of high prevalences in their countries of origin and barriers in access to healthcare in the recipient countries. Consequently, we aimed to compare and investigate differences in mortality from infectious diseases among refugees and immigrants and native Danes.

Methods  A register-based, historical prospective cohort design. All refugees (n = 29 139) and family-reunited immigrants (n = 27 134) who, between 1 January1993 and 31 December1999, were granted the right to reside in Denmark were included and matched 1:4 on age and sex with native Danes. Civil registration numbers were cross-linked to the Register of Causes of Death, and fatalities owing to infectious diseases (based on ICD-10 diagnosis) were identified. Mortality ratios were estimated separately for men and women by migrant status and region of birth; adjusting for age and income; using a Cox regression model, after a mean follow-up of 10–12 years after arrival.

Results  Female [hazard ratio (HR) = 4.15; 95% CI: 2.38, 7.25] and male (HR = 2.05; 95% CI: 1.27, 3.33) refugees experienced significantly higher mortality risks from infectious diseases than did native Danes, as was the case for male immigrants (HR = 2.39; 95% CI: 1.20, 4.76) but less so for female immigrants (HR = 1.23; 95% CI: 0. 50-3.01). Mortality by region of origin was notably higher for individuals from North Africa and sub-Saharan Africa.

Conclusions  Higher mortality among refugees and immigrants than among the native population should lead to reflections on medical reception systems in recipient countries and subsequent possibilities of access to specialised diagnostic and curative healthcare.

Objectifs:  Les réfugiés et les immigrants sont susceptibles d’être vulnérables à la mortalité due aux maladies infectieuses en raison de la prévalence élevée dans leur pays d’origine et des obstacles à l’accès aux soins de santé dans les pays hôtes. Par conséquent, nous avons cherchéà comparer et à enquêter sur les différences de mortalité par maladies infectieuses chez les réfugiés/immigrés et les Danois de souche.

Méthodes:  Une étude prospective de cohorte historique basée sur les registres. Tous les réfugiés (n = 29.139) et immigrés de familles réunies (n = 27.134) qui, entre le 1er janvier 1993 et le 31 décembre 1999 ont obtenu le droit de résidence au Danemark ont été inclus et appariés dans un rapport ¼ pour l’âge et le sexe avec des Danois de souche. Les numéros d’immatriculation civile croisés au registre des causes de décès et les décès dus aux maladies infectieuses (sur base du diagnostic ICD-10) ont été identifiés. Les taux de mortalité ont été estimés séparément pour les hommes et les femmes selon le statut de migrant et la région de naissance, avec ajustement pour l’âge et le revenu, en utilisant un modèle de régression de Cox, après un suivi moyen de 10 à 12 ans après l’arrivée.

Résultats:  Les réfugiés féminins (RR = 4,15; IC95%: 2,38–7,25) et masculins (RR = 2,05; IC95%: 1,27–3,33) avaient un risque de mortalité par maladies infectieuses significativement plus élevé que les Danois de souche de même que les immigrés masculins (RR = 2,39; IC95%: 1,20–4,76) mais moins pour les immigrés féminins (RR = 1,23; IC95%: 0,50 – 3,01). La mortalité par région d’origine était notablement plus élevée pour les ressortissants d’Afrique du Nord et subsaharienne.

Conclusions:  La mortalité plus élevée chez les réfugiés et les immigrés que chez les autochtones devrait conduire à des réflexions sur les systèmes d’offre médicale dans les pays hôtes et les possibilités d’accès aux soins diagnostiques et curatifs spécialisés.

Objetivos:  Los refugiados e inmigrantes suelen ser vulnerables a la mortalidad por enfermedades infecciosas como resultado de la alta prevalencia en sus países de origen y de las barreras al acceso de cuidados sanitarios en los hogares que les acogen. En consecuencia, buscábamos comparar e investigar las diferencias en mortalidad por enfermedades infecciosas entre refugiados e inmigrantes y Daneses nativos.

Métodos:  Diseño histórico-prospectivo de cohortes, basado en registros. Se incluyeron todos los refugiados (n = 29,139) e inmigrantes reunidos con sus familias (n = 27,134) que obtuvieron la residencia en Dinamarca entre el 1 de Enero de 1993 y el 31 de Diciembre de 1999, y se les pareó 1:4 por edad y sexo con Daneses nativos. Los números de registro civil se cruzaron con los del Registro de Causas de Muerte, y se identificaron las muertes por enfermedades infecciosas (basándose en el diagnóstico ICD-10). Se calcularon las tasas de mortalidad para hombres y mujeres de forma separada, según estatus migratorio y lugar de nacimiento; ajustando para edad e ingresos; utilizando un modelo de regresión de Cox, después de una media de seguimiento de 10–12 años después de su llegada.

Resultados:  Los refugiados, tanto mujeres (RR = 4.15; 95%CI: 2.38; 7.25) como hombres, (RR = 2.05; 95%CI: 1.27;3.33) experimentaron un riesgo de mortalidad por enfermedades infecciosas significativamente mayor que los Daneses nativos, al igual que los inmigrantes hombres (RR = 2.39; 95%CI: 1.20; 4.76), pero era menor para inmigrantes mujeres (RR = 1.23; 95%CI:0. 50–3.01). La mortalidad por región de origen era notablemente más alta para individuos del Norte de África y África sub-Sahariana.

Conclusiones:  Una mayor mortalidad entre refugiados e inmigrantes que entre la población nativa debería conllevar a una reflección sobre los sistemas sanitarios de acogida en países receptores, y las subsecuentes posibilidades de acceso a pruebas diagnósticas especializadas y cuidados curativos.


Introduction

  1. Top of page
  2. Summary
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. References

In 2010, the migrant population in Europe was estimated to be 70 million, of whom 1.6 million were refugees (United Nations 2008). Among the migrants, our study focuses on refugees and family-reunited immigrants. From 1994 to the end of 2010, Denmark received approximately 75 000 refugees and 105 000 family-reunited immigrants (The Danish Immigration Service 2004; The Ministry of Refugee, Immigrant and Integration Affairs 2009, 2010). Refugees may enter Denmark as spontaneous asylum seekers or as quota refugees. The first group arrives in Denmark under its own means, whereas around 500 quota refugees have arrived in Denmark annually since 1985 under an agreement between the Danish State and the United Nations High Commissioner for Refugees (UNHCR). The Danish Red Cross is responsible for asylum seekers’ healthcare and living conditions in cooperation with the Danish Immigration Service during the asylum-seeking procedure. In contrast, quota refugees automatically have right to residency and are immediately dispersed in municipalities throughout Denmark where they are assigned housing and a general practitioner. Lastly, family-reunited immigrants rely entirely on their family when establishing life in exile, both regarding housing and establishing initial contact with health care providers. In this study, family-reunited immigrants are henceforth named ‘immigrants’, and ‘migrants’ refers to all groups of foreign-born individuals.

Studies from European countries show lower all-cause mortality estimates among non-Western migrants than among the native born, which has been attributed, for example, to better access to healthcare in recipient countries, ‘the healthy migrant effect’ and remigration of (terminally) ill individuals (Razum et al. 1998; Bos et al. 2004). In contrast, mortality from infectious diseases is estimated to be higher among non-Western migrants than among natives (Bos et al. 2004; Stirbu et al. 2006). This is disconcerting because mortality from most infectious diseases should be avoidable in the setting of European health care services.

Our hypothesis was that migrants are more vulnerable to death from infectious diseases than from native Danes owing to a series of risk factors associated with migration. First, many refugees and immigrants come from countries with a high prevalence of infectious diseases and poor access to diagnosis and treatment. Especially refugees may have been exposed to strenuous living conditions before and after exile, including problems in accessing healthcare during flight or in refugee camps, resulting in an increased risk of contracting infectious diseases. Second, although many European countries provide screenings, these often miss newly arrived migrants (Norredam et al. 2006). In Denmark, screening is systematically offered only to asylum seekers, but not to quota refugees and migrants. Third, migrants may lack knowledge about the health care system in the recipient country and consequently experience problems in accessing (specialist) care. Newly arrived migrants are particularly vulnerable.

To date, the documentation of infectious disease mortality among migrants is scarce in Europe: studies are based on ‘region of origin’ as the determinant and do not include migrant status (refugees vs. family-reunited immigrants); most studies concern well-established migrant groups and rarely recent arrivals; and no data exist from Denmark or the other Nordic countries. To overcome some of these shortcomings, we conducted a national register-based study of the mortality risk from infectious diseases among refugees and immigrants after a median follow-up of 10–12 years after arrival and compared it with the mortality risk among native Danes.

Methods

  1. Top of page
  2. Summary
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. References

Study cohort

The study cohort was obtained through the statistics department at the Danish Immigration Service. All migrants who obtained right of residency as refugees or through family reunification in Denmark between 1 January 1993 and 31 December 1999 were included; 84 379 individuals were identified. Those younger than 18 years (= 18 861) when they obtained residency were excluded. Individuals less than 18 years were excluded as the original studies deriving from the cohort focused on morbidity and health care use among adult migrants in relation to cancer and mental illness (Norredam et al. 2007, 2008, 2010). Another 3042 individuals were excluded owing to missing civil registration number or because their personal security numbers appeared more than once in the sample. 15 migrants and their controls were excluded owing to problems with their registration of nationality. A Danish-born reference population was identified through Statistics Denmark, and a 4:1 match on an individual level on age and sex was performed through a random sampling procedure. We were able to make a 4:1 matching for all refugees. Four immigrants were missing a total of five controls because of the difficulties with age matching because of outlying ages. This sampling was chosen to optimise the group comparisons, i.e., refugees vs. controls and immigrants vs. controls. Further, this matched sampling resulted in an age distribution among controls, which is identical to that among the refugees (or immigrants), and therefore, non-adjusted mortality rates for refugees and controls may be compared directly. The study cohort and matching procedure has previously been described in more detail (Norredam et al. 2010). Lastly, 6188 migrants born in Western Countries were excluded from the cohort with their corresponding controls. The final cohort comprised 29 139 refugees (controls: 116 556) and 27 134 immigrants (controls: 108 534). Migrants were consecutively censored on their first registered emigration date and were not included again if they later returned to Denmark. Follow-up time was thus defined for both refugees and immigrants and their corresponding controls as the time from the commencement of right of residency until the time of the first of the following events: (i) date of death; (ii) end of study (31.12.2007); or (iii) date of first emigration. Characteristics of the study population are shown in Table 1.

Table 1.   Characteristics of the study cohort. Refugees (n = 29 139) and immigrants (27 134) and their matched Danish-born control groups distributed by sex
 Female refugeesDanesMale refugeesDanesFemale immigrantsDanes % (n)Male immigrantsDanes
% (n)% (n)% (n)% (n)% (n)% (n)% (n)% (n)
  1. *31.12.2007.

  2. **31.12.1999.

Regional of origin
 Asia1.8 (238) 3.1 (509) 27.3 (4996) 10.8 (955) 
 East Europe2.0 (258) 1.8 (297) 16.8 (3100) 5.4 (481) 
 Former Yugoslavia57.2 (7404) 49.2 (7965) 5.7 (1038) 9.8 (856) 
 Iraq11.3 (1464) 19.5 (3154) 6.5 (1185) 2.0 (180) 
 Middle East10.3 (1329) 10.0 (1625) 27.8 (5088) 47.3 (4140) 
 North Africa15.7 (2031) 14.5 (2335) 9.8 (1826) 15.0 (1322) 
 Sub-Saharan Africa1.7 (225) 1.9 (305) 6.1 (1121) 9.7 (846) 
 Total100 (12 949)100 (51 796)100 (16 190)100 (64 760)100 (18 354)100 (73 416)100 (8780)100 (35 118)
 Sex44.4 (12 949)44.4 (51 796)55.6 (16 190)55.6 (64 760)67.6 (18 354)67.6 (73 416)32.4 (8780)32.4 (35 118)
Events during follow-up
 Total deaths3.7 (481)4.7 (2451)4.0 (657)5.2 (3377)0.9 (171)1.9 (1411)1.6 (143)3.3 (1164)
 Emigrations13.6 (1765)3.8 (1977)14.3 (2324)5.0 (3212)17.6 (3222)6.0 (4458)23.0 (2017)6.6 (2333)
 Population at closure**82.7 (10 703)91.5 (47 368)81.7 (13 209)88.8 (58 171)81.5 (14 961)92.1 (67 547)75.4 (6620)90.1 (31 621)
 Median age at entry33.1 (26.5;42.9)33.1 (26.5;42.9)32.6 (26.4;41.0)32.6 (26.4;41.0)26.6 (22.2;33.1)26.6 (22.2;33.1)27.0 (23.4;32.5)27.0 (23.4;32.4)
 Median age at study end*44.3 (37.1;54.2)44.7 (37.7;54.5)43.5 (37.0;52.2)43.9 (37.6;52.4)36.8 (32.1;43.4)37.5 (32.8;44.1)36.9 (32.8;42.2)37.6 (33.8;43.3)
 Median follow-up in years12.1 (10.3;12.4)12.1 (10.7;12.5)11.9 (9.7;12.4)12.1 (10.5;12.5)10.6 (9.0;12.4)10.9 (9.2;12.6)10.5 (9.0;12.2)10.8 (9.2;12.4)

Data collection

Civil registration numbers of the study cohort were cross-linked to the Danish Register on Causes of Death, which has data based on the report of death certificates to the National Board of Health. The register was updated to 31 December 2007. Death causes were coded according to the International Classification of Diseases, tenth revision (ICD-10). The register has used the ICD-10 coding system since 1 January 1994, which was a change from the ICD-8 coding system previously used. As the validity of the translations in the register from ICD-8 to ICD-10 is questionable, we decided to use only ICD-10 diagnoses starting from 1 January 1994 (although the cohort was established from 01.01.1993). Among all deaths (n = 9855) in the cohort, 168 individuals were missing cause of death and were consequently excluded from the study at their date of death. Data in the Register of Causes of Death are grouped into 14 major causes of death of which the first two concern infectious diseases: (i) tuberculosis, including late-stage complications (ICD-10: A15-A19, B90), and (ii) other infectious diseases including HIV/AIDS (ICD-10: A00-A09, A20-A99, B00-B89, B91-B99). A similar classification was also used previously (Bos et al. 2004). All deaths between 1 January 1994 and 31 December 2007 related to these diagnostic ICD-10 groups were identified, totalling 51 refugees (controls: 81) and 16 immigrants (controls: 26).

Data on income were obtained from Statistics Denmark. The variable on income is updated annually on 31 December. Personal income was divided into three categories: low (<13 500 €/year), middle (13 500–40 500 €/year) and high (>40 500 €/year). In total, 848 individuals such as, 113 refugees (controls: 224) and 368 immigrants (controls: 143), did not have a registered income by 31 December 2007. These individuals were all excluded from our analysis, which was consequently based on 29 026 refugees (controls: 116 332) and 26 766 immigrants (controls: 108.391). Region of birth was categorised into the seven most common geographical regions of origin/countries in the cohort, according to World Health Organisation (2003): Asia, Eastern Europe, former Yugoslavia, Iraq, Middle East, North Africa and sub-Saharan Africa.

Analysis

We estimated the HR and 95% confidence intervals for mortality by infectious disease among refugees and immigrants compared with their Danish-born controls using a Cox regression model (in SAS version 9.1), which was fitted separately for men and women. Native Danes form the reference group. The Cox regression analysis implies a continuous adjustment for age in the model based on the assumption that the age distribution is the same in all groups. Hazard ratios analysed by both migrant status and region of birth and adjusted for income. The analyses take into consideration the time during which an individual has been in a certain income category and allows for people changing from one income category to another over time. We assumed that the effect of income on mortality was the same for refugees, immigrants and controls. Before making this assumption, we analysed the influence of interaction terms, e.g., migrant status*region of origin*income, on the infectious disease-specific mortality finding no significant interactions. Firstly, we studied the unadjusted HR, and then, the HR adjusted for income. As these separate analyses gave the same conclusion, Table 2 shows only the adjusted rates. The Cox regression model allows us to compare the relative risk for refugees with that of immigrants and not only with that of their Danish-born controls.

Table 2.   Hazard ratios (HR) of sex specific mortality from infectious diseases estimated by migrant status and region of birth, adjusting for age and income. Danish born controls form the reference group. Analyses are based on data from 1.1.1994 to 31.12.2007
Region of originFemale refugeesMale refugees
HR95%CIP-valuen*(n)†HR95%CIP-valuen*(n)†
  1. *Fatalities among refugees and immigrants.

  2. †Fatalities among controls.

Asia0.000(1)5.04(1.22; 20.80)0.0252(2)
Eastern Europe0.000(0)0.000(0)
Former Yugoslavia1.54(0.64; 3.73)0.3346(15)1.40(0.72; 2.74)0.31413(34)
Iraq2.35(0.32; 17.20)0.4011(3)0.51(0.07; 3.71)0.5061(10)
Middle East0.000(3)0.72(0.10; 5.21)0.7451(1)
North Africa18.43(8.48; 40.07)<0.00019(3)9.58(4.82; 19.07)<0.000110(8)
Sub-Saharan Africa195.7(79.23; 483.2)<0.00016(0)8.11(1.11; 58.99)0.0392(2)
Total4.15(2.38; 7.25)<0.000122(25)2.05(1.27; 3.33)0.00429(56)
 Female immigrantsMale immigrants
Asia0.79(0.11; 5.82)0.8151(4)2.50(0.60; 10.42)0.2082(1)
Eastern Europe0.00(2)7.73(1.85; 32.29)0.0052(2)
Former Yugoslavia0.00(0)0.00(0)
Iraq0.00(1)0.00(0)
Middle East0.00(2)1.26(0.30; 5.25)0.7462(5)
North Africa2.90(0.39; 21.40)0.2971(3)1.64(0.23; 11.89)0.6251(5)
Sub-Saharan Africa22.48(7.63; 66.22)<0.00014(0)10.25(3.15; 33.33)<0.00013(0)
Total1.23(0.50; 3.00)0.6516(12)2.40(1.21; 4.79)0.01310(14)

Results

  1. Top of page
  2. Summary
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. References

The median age at study end was 44 years among refugees and 37 years among immigrants. The median follow-up time was 10–12 years. Women comprised 44% of refugees and 68% of immigrants. Approximately half of the refugees in the cohort came from former Yugoslavia, whereas immigrants originated mainly from the Middle East and Asia.

Table 2 shows that overall, female refugees had a fourfold significantly increased mortality risk (HR = 4.15; 95% CI: 2.38, 7.25) compared with Danish born; male refugees had a twofold increased mortality risk (HR = 2.05; 95% CI: 1.27, 3.33). Regarding the effect of region of birth, although absolute numbers were small, the mortality risk of female refugees from North Africa (HR = 18.43; 95% CI: 8.48–40.07) and sub-Saharan Africa (HR = 195.7; 95% CI: 79.23, 483.2) was markedly higher than that of Danish born. A similar effect of being born in Asia (HR = 5.04; 95% CI: 1.22, 20.80), North Africa (HR = 9.58; 95% CI: 4.82, 19.07) and sub-Saharan Africa (HR = 8.11; 95% CI: 1.11, 58.99) was seen among male refugees. Apart from this, no significant differences were found between the various regions of origin and native Danes.

Table 2 also shows the HR of sex-specific mortality from infectious diseases among immigrants compared with their Danish-born comparison group. Overall, mortality risk did not differ significantly between female immigrants and their Danish-born control group (HR = 1.23; 95% CI: 0.50, 3.00), whereas for male immigrants, mortality risk was twice as high as for native men (HR = 2.40; 95% CI: 1.21, 4.79). Regarding the effect of region of birth, there was a significantly higher risk among female immigrants from sub-Saharan Africa (HR = 22.48; 95% CI: 7.63, 66.22) than among Danish born, although absolute numbers were small. A similar effect of being born in Eastern Europe (HR = 7.73; 95% CI: 1.85, 32.29) and sub-Saharan Africa (HR = 10.25; 95% CI: 3.15, 32.33) was seen among male immigrants, although the first was only borderline significant. Apart from this, no significant differences were found between the various regions of origin among immigrants and native Danes.

Table 3 shows the frequency distribution of infectious disease mortality by specific disease categories (ICD-10) among refugees and immigrants compared to their Danish-born controls. Generally, more migrants were likely to die from tuberculosis, AIDS and hepatitis than their Danish-born counterparts, who were more likely to die from ‘other’ infectious diseases. Specifically, female refugees (36.4%vs. 0.0%) and female immigrants (83.3%vs. 25%) died more often from AIDS than native controls, whereas male refugees and immigrants less often had AIDS as a death cause than native controls.

Table 3.   Frequency distribution of infectious disease mortality by specific infectious disease categories (ICD-10) among refugees and immigrants compared to their Danish born controls. Analyses are based on data from 1.1.1994 to 31.12.2007
Specific infectious mortality causes according to ICD-10Female refugeesDanesMale refugeesDanesFemale immigrantsDanesMale immigrantsDanes
%n%n%n%n%n%n%n%n
  1. *Total (100%) refers to all deaths due to infectious diseases in the cohort.

TB (A15-19, B90)9.124.0124.171.8116.7117.0220.02
AIDS (B20-24)36.4817.2539.32283.3525.0340.0450.07
Viral hepatitis (B15-19)18.2427.68  10.01
Other (A39, A00-09, A20-99, B00-09, B25-89, B91-99)36.4888.02431.0958.93358.0730.0350.07
Total*100221002510029100561006100121001010014

Discussion

  1. Top of page
  2. Summary
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. References

Our study showed that in total, female and male refugees experienced significantly higher mortality risks from infectious diseases than native Danes. This was also the case for male, but not female, immigrants. Mortality was significantly higher for refugees from Asia, North Africa and sub-Saharan Africa and immigrants from Eastern Europe and sub-Saharan Africa, whereas the remaining regional subgroups did not differ consistently from native Danes. The results are supported by two Dutch studies (Bos et al. 2004; Stirbu et al. 2006), which likewise show a general tendency towards higher mortality from infectious diseases among migrants compared with that among natives, although the studies did not use migrant status as a determinant but only region of origin.

There may be several interacting factors playing a role in the documented differences. (i) They may reflect increased morbidity owing to infectious exposure in countries of origin and also more advanced disease upon arrival. This could explain why individuals from regions with high prevalences of infectious diseases, such as North Africa (including Somalia) and sub-Saharan Africa, have notably higher mortality risks (Williamson et al. 2009). A high prevalence of these infectious diseases, including HIV/AIDS (Norman et al. 2010; Udayaraj et al. 2009), tuberculosis (Statens Serum Institut 2006; Lillebaek et al. 2002), hepatitis (Gjorup et al. 2003) and some other vaccine-preventable diseases (Gushulak & MacPherson 2004), have also been reported both among newly arrived migrants and more well-established groups of migrants in immigration countries. (ii) Ineffective or non-existent screening programmes upon arrival may account for lack of earlier diagnosis. The content and target group of screening programmes vary across and within European countries (Norredam et al. 2006; François et al. 2008). Although Denmark’s National Board of health has issued a guide (National Board of Health 2002) on how to handle infectious disease among migrants, it has not led to any official policy or practical implementation of consequence to the screening of new arrivals. The Danish Red Cross offers a nurse-directed voluntary physical and mental health screening of all new asylum seekers. Infectious diseases are screened for only if the attendee reveals symptoms during the consultation. As for quota refugees, it is at the discretion of the local municipality caseworker or individual general practitioner whether individuals are medically screened upon arrival. There is no screening programme for family-reunited immigrants upon arrival nor a systematic update according to the Danish vaccination programme. Thus, lack of effective screening programmes may have contributed to our results.

Tuberculosis screening should receive special consideration as screening upon arrival is not sufficient to detect latent disease that may later become active. Somali migrants remain at high risk even several years after arrival (Lillebaek et al. 2002). The implications for health, ethics and costs of insufficient or non-existing screening programmes have been addressed and documented, but evaluations and models of best practice are lacking (Veldhuijzen et al. 2010; Coker 2004; Blumberg et al. 2010; Fätkenheuer et al. 1999). (iii) It has been argued that substandard housing, overcrowding and poor sanitation may contribute to increased risks of infectious diseases among migrants (Fätkenheuer et al. 1999; Bos et al. 2004). Indeed, in Denmark and other countries, refugees and immigrants tend to be less educated, have lower incomes and lower job rates, which may be linked to substandard living environments (Statistics Denmark 2010). (iv) Restrictions on legal access to healthcare for certain migrant groups may increase disease severity. In Denmark, asylum seekers are not included under the Danish National Health Insurance System; however, in principle, they have access to acute care. If specialist treatment is needed, a doctor from the Danish Red Cross must apply to the Danish Immigration Service for treatment costs to be covered. Once asylum seekers obtain refugee status and their consequent residency, they are included under the Danish National Insurance System just as quota refugees and family-reunited immigrants, who already have residency when they arrive (Norredam et al. 2006). (v) Lack of knowledge about the use of health care services and language barriers may impair access. Neither quota refugees nor family-reunited immigrants are offered any introduction to the Danish health care system upon arrival, including facilitating contact to general practitioners, which may impede access. (vi) Lack of specialised services, including lack of doctors specialised in migrants’ health issues, may delay referral and access to relevant healthcare and increase disease severity. However, the first hospital clinic specialising in migrant health has recently been established in Denmark. This has already helped create medical knowledge and raise professional awareness.

Methodological strengths and limitations

Our study used the unique Danish possibilities of cross-linkage between several different national registers. This enabled us to identify a large cohort of refugees and family-reunited immigrants based on specific information on migrant type from the immigration authorities and divide refugees and immigrants according to seven geographical subgroups. The design allowed us to calculate death rates over 11 years’ follow-up rather than using only prevalence rates; this enabled us to compare directly with a matched group of native Danes.

There are several factors that may have influenced the results of this study: although based on a relatively large cohort of migrants, absolute numbers become relatively small when specific diseases are investigated and stratification is undertaken according to region of birth and migrants status. Despite this power problem, our analyses were significant. However, further analysis according to specific infectious disease was not possible apart from a frequency distribution (Table 3). The Register on Causes of Death did not receive death certificates for 3–4% of all the annual deaths that were registered in the Population Register at Statistics Denmark. In addition, 3% of all death certificates in the Registry of Causes of Death during the study period had ‘unknown’ cause of death listed. Although there may be differences between migrants and Danes here, they are unlikely to be substantial. Our results may have also been affected by registered or unregistered remigration, which would have skewed the denominator figures. Thus, remigration of healthy individuals may inflate our results, whereas remigration of critically ill individuals with infectious diseases who then die abroad would have led to an underestimation of our results (so-called re-migration bias). We have no means of taking these biases into consideration as we do not know the extent of remigration in relation to these two points. Deaths abroad of individuals with a Danish personal identification number are reported to Danish authorities on an irregular basis, but those death certificates sent to the Register of Death Causes are not included owing to validity problems. Finally, we controlled for income, but other measures, such as number of family members in household, marital status, employment status, would be interesting to investigate in the future.

In conclusion, our results document an overall higher risk of death from infectious diseases both among refugees and immigrants and an according need for better diagnosis and healthcare for migrants with such diseases in a Danish context. On the national level, voluntarily screening on arrival and information about the Danish health care system should reach all newly arrived migrants. A general health assessment should include tuberculosis screening as well as exploring vaccination status and important infectious disease such as HIV and hepatitis. Preferably, these initiatives should be carried out in cooperation between specialised clinicians and clinics and with existing health care pathways, including general practitioners. This has earlier been documented for Vietnamese refugees arriving in Denmark (Kjersem et al. 1982). On the EU level, relevant institutions should support the development of coordinated best practice models within the area of screening programmes and healthcare for migrants.

References

  1. Top of page
  2. Summary
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. References
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