SEARCH

SEARCH BY CITATION

Keywords:

  • mortality; minority groups; transients and migrants; Germany; Turkey

Abstract

  1. Top of page
  2. Abstract
  3. Introduction
  4. Materials and methods
  5. Results
  6. Discussion
  7. Acknowledgements
  8. References

Summaryobjective To test the hypothesis that as a minority with lower socio-economic status, Turkish residents in Germany might experience a higher mortality than Germans.

methods All-cause mortality rates by age group and sex of Turkish and German adults for the time period 1980–94 were calculated from death registry data and mid-year population estimates.

results The age-adjusted mortality rate (per 100000) of Turkish males aged 25–65 years resident in Germany was 299 in 1980 and 247 in 1990, consistently half that of German males. The mortality of Turkish females in Germany was 140 in 1990, half that of German females. Mortality of Turkish males/females in Ankara was 835 and 426 in 1990.

conclusion In view of the socio-economic status of Turkish residents in Germany the large mortality difference compared to Germans is unexpected. It cannot be fully explained by a selection at the time of hiring (healthy migrant effect) because it lasts over decades and extends into the second generation. A healthy worker effect is unlikely because Turkish residents have a lower employment rate than Germans. There is little evidence for movement of gravely ill persons back to Turkey. An ‘unhealthy re-migration effect’ in which socially successful migrants with a lower mortality risk stay in the host country while less successful ones return home even before becoming manifestly ill would partly explain our findings.


Introduction

  1. Top of page
  2. Abstract
  3. Introduction
  4. Materials and methods
  5. Results
  6. Discussion
  7. Acknowledgements
  8. References

Migration within Europe is an on-going social phenomenon of large scale. It affects the health of individual migrants as well as that of populations (Bollini & Siem 1995; Elkeles & Seifert 1996). Since the 1950s, millions of people have temporarily migrated to Germany looking for work. About 900 000 people came from Turkey between 1963 and 1973. Many of these Gastarbeiter (guestworkers) settled and brought their families. They were joined by asylum seekers from Turkey. Turkish nationals now form the largest foreign nationality group in Germany. Their number increased from 1.5 to 2 million between 1980 and 1994 (Statistisches Bundesamt 1996), with a brief decrease in 1985 after financial incentives for re-migration were offered by the German Government.

People who migrate, whether their move is temporary or permanent, are on average healthier than the population they originate from, and often also healthier than the population of their host country (Swerdlow 1991; Williams 1993; Parkin 1993). This ‘healthy migrant effect’ is due to a self-selection process: the chronically ill and disabled are less likely to migrate. Among migrants there are also particularly courageous, innovative and socially skilled individuals (Schiffauer 1991).

Once they have moved to their host country, however, migrant workers are often a minority with lower social status than the host population. Numerous studies show that low socio-economic position and minority status are associated with chronic stress (Collatz 1994), higher morbidity (Marmot et al. 1991; Bollini & Siem 1995; Elkeles & Seifert 1996) and mortality (Davey Smith et al. 1990; Geronimus et al. 1996). Foreign nationals employed in Germany were found to have particularly high health risks (Oppen 1985; Elkeles & Seifert 1996) and higher occupational accident rates (Weber et al. 1990) than Germans; chronic diseases are more frequent and emerge at a younger age (Collatz 1994). Turkish residents in Germany are believed to suffer from more severe forms of coronary heart disease than Germans at a younger age (Bilgin et al. 1994). They also have higher unemployment rates (Sen 1996) and less access to appropriate medical care (Collatz 1994). Many second-generation Turkish nationals born in Germany are not fully integrated into either the German or the Turkish culture (Collatz 1996).

So far, one study (Weber et al. 1990) compared mortality rates of foreigners in Germany (not differentiated by nationality) to mortality rates of the German population for the period 1984–86. In the age group 35 to 65 years, age-standardized all-cause mortality of foreigners was roughly half that of Germans. The authors assumed that this was due to a healthy migrant effect and re-migration of severely ill individuals.

Little is known about time trends in mortality of migrants. Cancer mortality rates in immigrants tend to be lower initially and converge upon the rates of the host population with increasing length of stay (Thomas & Karagas 1987). Regarding all-cause mortality, there are indications that initial advantages in comparison with the host population may be maintained over years (Swerdlow 1991; Balzi et al. 1993) before wearing off (Williams 1993; Chaturvedi & McKeigue 1994), but data are scarce.

Thus the hypothesis emerges that the mortality rate of migrants from Turkey to Germany would initially have been lower than that of Turks residing in Turkey and possibly that of Germans. Over time and in the second generation, the healthy migrant effect would wear off. To test this hypothesis we compared all-cause mortality of Turkish residents in Germany, Germans, and Turks living in Turkey in the period 1980–94.

Materials and methods

  1. Top of page
  2. Abstract
  3. Introduction
  4. Materials and methods
  5. Results
  6. Discussion
  7. Acknowledgements
  8. References

We extracted all-cause mortality of Turkish nationals residing in (former West) Germany in the time period 1980–94 from annual registry data and calculated age and sex-specific as well as age-standardized mortality rates. For comparison, we present mortality rates of adult Germans and of the adult population of Ankara in Turkey. Rates for the age group 25 to under 65 years were obtained by direct standardization using deaths in 5-year age bands (Ankara: 10-year bands) and the German ‘standard’ population of 1987 (Statistisches Bundesamt 1991).

Denominator populations and death registration in Germany

Population figures 1980 to 1994 by sex and age group of Germans and of Turkish nationals residing in Germany were obtained from the Federal Statistical Office. German population figures are projected forward anually, based on the 1970 and 1987 census results. Population figures of foreigners are continuously updated by the central registry of foreigners. From age 65 years upwards, the number of Turkish residents is small and a breakdown by age is not available. As some retirees remain registered in Germany but spend considerable time in Turkey, their deaths may not be registered in Germany. Therefore we excluded the age group 65 years and above from the analysis. Data on migration, unemployment and naturalization were compiled from official sources (Statistisches Bundesamt 1980–1994; Cornelsen 1990; Statistisches Bundesamt 1996).

Death figures of Germans based on death certificates were supplied by the Federal Statistical Office. Deaths of foreign residents are registered by nationality only at the statistical offices of the federal states; the place of birth is not specified. Mortality data for Turkish residents are not routinely available. For this study, data from all federal states of former West Germany were compiled at the statistical office of the state of Baden-Württemberg. Figures exclude Turkish visitors to Germany and former Turkish nationals who obtained a German passport (double citizenship is not legally possible).

To calculate death rates, we estimated mid-year populations (MYP) as the mean of the population on 31 December of the actual and of the preceding year. For 1980–84, population figures for Turkish residents are available only for 30 September. We used these directly as the best available estimate of MYP.

Denominator population and death registration in Turkey

In Turkey, national censuses are carried out five-yearly with enumeration on a present-in-area basis (State Institute of Statistics 1980–1990a). Substantial internal migration affects the precision of estimates for between-census years. Deaths (but not mortality rates) are reported from province and district centres (State Institute of Statistics 1980–1990b). It is assumed that in spite of legal notification requirements there is underreporting of deaths, particularly in rural areas. For this reason we present mortality data for Ankara only. To obtain denominators for death rates we used estimates of the total mid-year population for Ankara's provincial and district centres 1980, 1985 and 1990 and broke them down by age and sex according to the census results (State Institute of Statistics 1980–1990a).

Results

  1. Top of page
  2. Abstract
  3. Introduction
  4. Materials and methods
  5. Results
  6. Discussion
  7. Acknowledgements
  8. References

Turkish population in Germany

Figure 1 shows the population development of Turkish men in 10-year age groups. A generation gap is clearly visible: the number of individuals aged 35–45 years is decreasing due to ageing and re-migration; their number is not yet replenished as the second generation is still mostly under 35 years of age. For females, this effect is less pronounced (not shown). Re-migration rates in 1981 were around 5% for males aged 25–50 and 10% in males aged 50–65 years; they decreased to below 4% in both groups from 1990 onwards. In females aged 25–50 re-migration decreased from 3% in 1981 to 2% from 1990 onwards, and in those aged 50–65 from 6% to about 3%. In 1994, 64% of Turkish residents had been in Germany for 10 years or longer (not controlled for age). Immigration is 2–3% per year. In 1987, 34% of immigrants were children under 18 and 17% were asylum seekers (0.8% of the migrant population). The majority were persons who had stayed in Germany before.

image

Figure 1. Population size, by 10 year age groups, of Turkish males resident in Germany. —– 25–34, ····· 35–44, –––– 45–54 and —·—· 55–64 years. Based on figures supplied by Statistiches Bundesamt.

Download figure to PowerPoint

Deaths

In the period 1980–94, the total number of deaths among Turkish nationals residing in Germany was 29148. Of these, 12210 (42%) were people below 25 years of age and 1652 (6%) were people 65 years and older. The remaining 15286 deaths, 11451 (75%) of which were men, occurred in the age group 25–64 years.

Figure 2 shows all-cause mortality rates per 100000 population in 10-year age groups for the years 1980–94. Turkish residents in Germany consistently have the lowest rates, 35–70% lower than that of Germans of the same sex and age group. Death rates in Ankara are higher. German mortality rates decrease over time, mainly as a consequence of decreasing cardiovascular mortality. For Turkish residents in Germany, a decrease is less distinct. Low case numbers among females in the early 1980s lead to unstable estimates. However, there is no indication of increasing mortality, not even in the 1990s when the second, partly German-born generation reaches the ages of 25–34. Figure 3 summarizes the findings by showing truncated age-standardized rates for males and females aged 25–64 years.

image

Figure 2. Mortality rates in 10 year age groups. a–d, Males (closed symbols); e–h, Females (open symbols). ○, • Turks in Germany; ▵, ▴ Germans; □, ▪ Turks in Ankara.

Download figure to PowerPoint

image

Figure 3. Age standardized and mortality rates for age group 25–64 years. a, Males; b, Females. ○, • Turks in Germany; ▵, ▴ Germans; □, ▪ Turks in Ankara.

Download figure to PowerPoint

Discussion

  1. Top of page
  2. Abstract
  3. Introduction
  4. Materials and methods
  5. Results
  6. Discussion
  7. Acknowledgements
  8. References

We found no evidence to support our hypothesis of increasing mortality among Turkish nationals resident in Germany. On the contrary, they appear to have strikingly and persistently lower all-cause mortality rates than the German population and an urban population in Turkey. These are unexpected findings. Studies from the UK and the US show two to four-fold increased mortality in minorities and socio-economically disadvantaged groups compared to the general population (Davey Smith et al. 1990; Geronimus et al. 1996). Migrant studies have demonstrated a decreasing mortality differential over time (Williams 1993; Parkin 1993). A decreased mortality similar in size to the one we found has been reported in Vietnamese refugees to the UK; it persisted for 5–10 years after arrival (Swerdlow 1991). Thus, our findings may reflect research artefacts, environmental or biological differences between populations, or selection processes.

Research artefacts

It is highly unlikely that the mortality differential could be explained by errors in death registration or population statistics in Germany. The observed difference is large and stable over time, except for females in the early 1980s when the number of deaths was small. Communication problems or cultural differences that might bias cause-of-death assignment do not affect all-cause death rates. Illegal immigration would not have an effect as only registered individuals are counted among both denominator populations and deaths. Deaths in Turkey of Turkish nationals resident in Germany are not included in German death statistics. As Germans dying while outside Germany are also excluded, the resulting bias is balanced out. Mortality rates in Ankara, however, could be an underestimate due to under-reporting of deaths or an overestimate due to referred patients from rural areas dying there.

Environment and genetics

In many studies, socio-economic status was found to be a strong predictor of morbidity and mortality. Turkish residents in Germany have lower job ratings and lower income which would explain a higher rather than the observed lower mortality. In recent years, numerous Turkish residents have started businesses of their own but this has not yet led to a major change in social composition (Sen 1996).

Regarding cardiovascular risk factor levels, Turkish residents might eat a healthier (Mediterranean) diet than Germans, which, by reducing cardiovascular mortality, would result in a reduction of overall mortality. Available figures, however, suggest that risk factors such as smoking are at least as prevalent among Turkish males as among Germans (Bilgin et al. 1994).

Selection processes

The size of the mortality differential suggests that a selection process may be at work. Our data are based on population registers, not on the follow-up of individuals. While this approach is commonly used in migrant studies (Parkin 1993), it cannot satisfactorily account for individuals entering or leaving the population under study. Some conclusions, however, can be drawn regarding selection by healthy migrant effect, healthy worker effect, change of nationality and re-migration in case of grave illness.

Migrants constitute a self-selected population with better-than-average health status (Weber et al. 1990; Swerdlow 1991; Balzi et al. 1993). However, this effect is likely to wear off over time (Williams 1993; Chaturvedi & McKeigue 1994). Before 1973, Turkish ‘Gastarbeiter’ underwent a health exam before being hired, but this was said to be rather superficial and is unlikely to explain the low mortality decades later. Also, family members who followed were not examined, further diluting a healthy migrant effect over the years.

Another obvious explanation for the differential in mortality would be a ‘healthy worker effect’. Workers usually have lower overall death rates than the general population because chronically ill and disabled people are excluded from the workforce (McMichael 1976). Fifteen years after recruitment, this effect would not account for more than a 10% differential (Fox & Collier 1976); it can even reverse in workers living under adverse conditions (Juel 1994). Substantially larger reductions in mortality have only been observed immediately after recruitment (SMR = 0.37) (Fox & Collier 1976), among airline pilots (SMR = 0.63) who undergo regular health check-ups (Band et al. 1996) and among steel workers in Brazil (SMR < 0.5) where there is a huge socio-economic gap between employed and unemployed (Barreto et al. 1996). Neither would apply to Turkish residents in Germany.

The healthy worker effect is an unlikely explanation for the observed differential for additional reasons. First, the effect would attenuate with ageing of the workers (McMichael 1976; Fox & Collier 1976) which we did not observe. Second, the Turkish population in Germany consists not only of employed persons but also of their family members, of unemployed, chronically ill and jobless individuals. Since 1973, the employment rates of Turkish residents and of Germans have converged. In 1988, the employment rate of male Turkish residents (58.9%) was slightly lower than that of German males (60.5%); that of Turkish females (27.5%) was considerably lower than that of German females (37%). Furthermore, 76% of employed Turkish residents but only 44% of employed Germans had a manual job (Cornelsen 1990) which, in other countries, is associated with a higher mortality (Davey Smith et al. 1990). Immigration, at 1% per year in the age group of interest (Statistisches Bundesamt 1980–1994), cannot explain a persisting healthy worker effect.

Naturalization is a relatively small and recent phenomenon among Turkish residents in Germany; double citizenship is currently not a legal option. In 1994, 4067 Turkish nationals above 25 years of age (0.4% of the denominator population) attained German citizenship (Statistisches Bundesamt 1996). Considering the availability of equal medical treatment options for Turkish residents in Germany, it is unlikely that naturalization would be differential with regard to health status.

In 1994, the re-migration rate to Turkey was 2.9% in the age group 25 years and older (Statistisches Bundesamt 1980–1994). To fully explain the mortality differential, 4% of all returnees would have to re-migrate because of grave illness subsequently leading to death. Ensuing mortality rates of returnees would be 10–20 times those of the Turkish population in Germany, which should have raised attention. Re-migration to die at home has been observed in moribund cancer patients. It is unlikely in conditions such as cardiovascular disease for which medical treatment in Germany is readily available and almost free.

While Turkish residents are socio-economically disadvantaged compared to Germans, they are nonetheless an active and productive group (Sen 1996; Collatz 1996). Relative socio-economic differences within the Turkish population in Germany could be more important and smaller than those in comparison with Germans, leading to lower mortality (Wilkinson 1997). In addition, first-generation Turkish migrants may draw positive experiences from migration (Schiffauer 1991), e.g. achieving economic and social success. Integration into familial and religious networks offers potentially effective ways to deal with stress (Antonovsky 1996; Collatz 1996). Thus, Turkish residents in Germany, perhaps more so than Germans, may perceive a sense of cohesion in their lives that is ‘salutogenic’ (Antonovsky 1996), i.e. a protective resource. Success also influences re-migration plans: elderly Turkish residents planning to stay in Germany are significantly better socially integrated and satisfied with their life than those intending to re-migrate (Fabian & Straka 1993).

We thus propose an additional hypothesis to help explain the mortality differential. Unlike emigration to another continent, ‘Gastarbeiter’ type migration within Europe is temporary by intention (if not necessarily so in practice) and the migrants are comparatively mobile. In such migrant populations a continuous selection process might be taking place. Individuals and families who cope well socially and economically stay in the host country; those who fail (and thus might in future experience a higher mortality) re-migrate even before becoming manifestly ill. As a consequence of this (so far hypothetical) ‘unhealthy re-migration effect’, the population remaining in the host country is constantly selected according to low mortality risk. This effect should be discernible in other European countries with similarly dynamic migrant populations. It would have public health repercussions: effects of preventive activities for migrants would be difficult to evaluate in terms of morbidity and mortality, as those at highest risk return before disease becomes manifest.

To learn more about what distinguishes returnees from persons remaining in the host country, research needs to follow up individuals. Reaching a decision to re-migrate is likely to be a complex process. Thus it will be necessary to carry out qualitative studies in order to obtain information on the range of motives for re-migration.

From our data it should not be concluded that there is no need for activities to improve the health of Turkish residents in Germany. Overall mortality figures may fail to reveal excess mortality from specific causes warranting public health action. For many chronic diseases, morbidity and disability are disproportionately higher than mortality. Common health problems such as psychosomatic, psychiatric and musculo-skeletal disorders are not reflected by mortality statistics. Thus, when populations are compared, lower mortality rates do not necessarily indicate better health.

Acknowledgements

  1. Top of page
  2. Abstract
  3. Introduction
  4. Materials and methods
  5. Results
  6. Discussion
  7. Acknowledgements
  8. References

This study was supported by the German Federal Ministry of Health (Kapitel 1501 Titel 532 02 1996). The authors wish to thank Dr Baumann, Statistical Office Baden-Württemberg, Germany, for crucial assistance in obtaining mortality data of Turkish residents; and Professor Diesfeld, Director, Department of Tropical Hygiene and Public Health, Heidelberg University, for his continual support and encouragement.

References

  1. Top of page
  2. Abstract
  3. Introduction
  4. Materials and methods
  5. Results
  6. Discussion
  7. Acknowledgements
  8. References
  • 1
    Antonovsky, A (1996) The salutogenic model as a theory to guide health promotion. Health Promotion International 11, 1118.
  • Balzi D, Brancker A & Geddes M (1993) Canada. In
    Cancer in Italian Migrant Populations (eds. M. Geddes, DM Parkin, M Khlat, D Balzi & E Buiatti). IARC publications, Lyon, pp. 55–66.
  • 3
    Band, PR Le, ND Fang, R, et al (1996) Cohort study of Air Canada pilots: mortality, cancer incidence, and leukemia risk. American Journal of Epidemiology 143, 137143.
  • 4
    Barreto, SM Swerdlow, AJ Smith, PG Higgins, CD (1996) Mortality from injuries and other causes in a cohort of 21,800 Brazilian steel workers. Occupational and Environmental Medicine 53, 343350.
  • 5
    Bilgin, Y Arat, A Karatay, E, et al (1994) Risikofaktorprofil bei Patienten mit koronarer Herzerkrankung. Die Medizinische Welt 45, 136139.
  • 6
    Bollini, P Siem, H (1995) No real progress towards equity: Health of migrants and ethnic minorities on the eve of the year 2000. Social Science and Medicine 41, 819828.
  • 7
    Chaturvedi, N McKeigue, PM (1994) Methods for epidemiological surveys of ethnic minority groups. Journal of Epidemiology and Community Health 48, 107111.
  • 8
    Collatz, J (1994) Zur Realität von Krankheit und Krankheitsversorgung von Migranten in Deutschland. Jahrbuch für Kritische Medizin 23, 101132.
  • 9
    Collatz, J (1996) Die Welt im Umbruch. Zu Lebenssituation, Gesundheitszustand und Krankheitsversorgung von Migrantinnen und Migranten in Deutschland. Pro Familia Magazin 22, 26.
  • 10
    Cornelsen, C (1990) Erwerbstätigkeit von Ausländern 1988. Wirtschaft und Statistik 42, 8594.
  • 11
    Davey Smith, G Shipley, MJ Rose, G (1990) Magnitude and causes of socioeconomic differentials in mortality: further evidence from the Whitehall Study. Journal of Epidemiology and Community Health 44, 265270.
  • 12
    Elkeles, T Seifert, W (1996) Immigrants and health: unemployment and health-risk of labour migrants in the Federal Republic of Germany. Social Science and Medicine 43, 10351047.
  • 13
    Fabian, T Straka, GA (1993) Lebenszufriedenheit älterer türkischer Migranten. Zeitschrift für Gerontologie 26, 404409.
  • 14
    Fox, AJ Collier, PF (1976) Low mortality rates in industrial cohort studies due to selection for work and survival in the industry. British Journal of Preventive Social Medicine 30, 225230.
  • 15
    Geronimus, AT Bound, J Waidmann, TA Hillemeier, MM Burns, PB (1996) Excess mortality among blacks and whites in the United States. New England Journal of Medicine 335, 15521558.
  • 16
    Juel, K (1994) High mortality in the Thule cohort: an unhealthy worker effect. International Journal of Epidemiology 23, 11741178.
  • 17
    Marmot, MG Davey Smith, G Stansfeld, S, et al (1991) Health inequalities among British civil servants: the Whitehall II study. The Lancet 337, 13871393.
  • 18
    McMichael, AJ (1976) Standardized mortality ratios and the ‘healthy worker effect’: scratching beneath the surface. Journal of Occupational Medicine 18, 165168.
  • Oppen M (1985) Ausländerbeschäftigung, Gesundheitsverschleiss und Krankenstand. In
    Gesundheit für alle. Die medizinische Versorgung türkischer Familien in der Bundesrepublik. (eds. J. Collatz, E. Kürsat-Ahlers, & J. Korporal), EB-Verlag, Rissen, pp. 196–212.
  • Parkin DM (1993) Studies of cancer in migrant populations. In
    Cancer in Italian Migrant Populations (eds. M. Geddes, DM Parkin, M Khlat, D Balzi & E Buiatti) , IARC publications, Lyon, pp. 1–10.
  • Schiffauer W (1991)
    Die Migranten aus Subay. Türken in Deutschland: eine Ethnographie. Klett-Cotta, Stuttgart.
  • Sen F (1996) Türkische Migranten in Deutschland – ein Überblick. In
    Türken als Unternehmer (eds. F. Sen & A. Goldberg), Leske & Budrich, Opladen, pp. 11–45.
  • State Institute of Statistics (1980a, 1985a, 1990a)
    Census results Turkey. State Institute of Statistics, Ankara, Turkey.
  • State Institute of Statistics (1980b, 1985b, 1990b)
    Deaths Statistics (in Province and District Centres). State Institute of Statistics, Ankara, Turkey.
  • Statistisches Bundesamt (1980–1994)
    Fachserie 1, Reihe 1 und 2. Bevölkerung und Erwerbstätigkeit Statistisches Bundesamt, Wiesbaden.
  • Statistisches Bundesamt (1991)
    Fachserie 12 ‘Gesundheitswesen’. Statistisches Bundesamt, Wiesbaden.
  • Statistisches Bundesamt (1996)
    Statistisches Jahrbuch für die Bundesrepublik Deutschland 1996. Statistisches Bundesamt, Wiesbaden.
  • 28
    Swerdlow, AJ (1991) Mortality and cancer incidence in Vietnamese refugees in England and Wales: a follow-up study. International Journal of Epidemiology 20, 1319.
  • 29
    Thomas, DB Karagas, MR (1987) Cancer in first and second generation Americans. Cancer Research 47, 57715776.
  • Weber I, Abel M, Altenhofen L
    et al. (1990) Zur gesundheitlichen Lage der ausländischen Bevölkerung in der Bundesrepublik Deutschland: Erste Erkenntnisse. In Dringliche Gesundheitsprobleme der Bevölkerung in der Bundesrepublik Deutschland (ed. by Projektgruppe Prioritäre Gesundheitsziele), Nomos Verlagsgesellschaft, Baden-Baden, pp. 577–601.
  • 31
    Wilkinson, RG (1997) Health inequalities: relative or absolute material standards? British Medical Journal 314, 591595.
  • 32
    Williams, R (1993) Health and length of residence among South Asians in Glasgow: a study controlling for age. Journal of Public Health Medicine 15, 5260.