Differences in healthy life expectancy between older migrants and non-migrants in three European countries over time

In all three countries studied, migrants aged 50 years and older could expect to live fewer years in good self-rated health than non-migrants. Non-western migrants had the lowest HLE₅₀, especially in the Netherlands. The differences in HLE₅₀ between (non-western) migrants and non-migrants were mainly determined by differences in self-rated health. Between 2001 and 2011, migrant inequalities in both HLE₅₀ and HLE₅₀/LE₅₀ were reduced in the Netherlands, mainly driven by improvements in self-rated health among non-western migrants. While migrant inequalities in HLE₅₀ diminished among males in England and Wales, migrant inequalities in HLE₅₀/LE₅₀ increased for both sexes.

The results of our analysis are based on highly reliable population and health data. Nevertheless, several limitations of the study should be noted. Although self-rated health has been reported to be reliable for the total population, concerns have been raised about its use when comparing different ethnic groups (e.g. Chandola and Jenkinson 2000). Seo et al. (2014), however, found that variations in the response patterns do not differ according to origin, but to the responding language instead. In our study, census and surveys were provided in the national languages only, which helps reducing the potential variability in the response pattern between migrants and non-migrants. Furthermore, studies of older migrants that relied on more objective health indicators, such as depression, functioning, or disability (Solé-Auró and Crimmins 2008; Lanari and Bussini 2012; Carnein et al. 2014), found similar results, i.e. migrants are less healthy than non-migrants.

Our data might also suffer from comparability issues between countries and over time. Even when the same question format is used, self-rated health outcomes reported by the older population in surveys may vary due to differences in survey response, sample size, and survey mode (Croezen et al. 2016). For instance, the exclusion of people living in institutions from the sample frame in the Netherlands might have led to an overestimation of HLE₅₀, as a high share of the population—and especially non-migrants and western migrants—live in institutions after age 80. In England and Wales, the self-rated health data in the 2001 census were originally classified in three response categories instead of five. Although we applied adjustment factors to ensure comparability across countries and over time, the adjustment factors are less reliable among the oldest old (Smith and White 2009). To assess the influence of these data limitations on our HLE₅₀ estimations, we performed a sensitivity analysis excluding the population aged 80 and over. We therefore calculated the temporary healthy life expectancy between ages 50 and 79 (THLE₅₀₋₇₉) by applying the Sullivan method (1971) to the temporary life expectancy (Arriaga 1984) between ages 50 and 79 (results not shown). The most remarkable difference found in both analyses was that the THLE₅₀₋₇₉ for females in England and Wales increased between 2001 and 2011, while the HLE₅₀ decreased. The THLE₅₀₋₇₉ gap between non-migrants and non-western migrants in the Netherlands was also smaller than the HLE₅₀ gap; thus supporting the assumption that the large migrant health inequalities in the Netherlands were, at least partially, attributable to the exclusion of the institutionalized population from the sample frame. Nevertheless, similar patterns were found in HLE₅₀ and THLE₅₀₋₇₉ when comparing migrants and non-migrants across countries, and when comparing trends over time. In light of the outcomes of these additional THLE₅₀₋₇₉ analyses, we may not be able to identify with certainty the countries in which older migrants have a longer or a shorter HLE₅₀. However, we can conclude that older migrants, especially those of non-western origin, can expect to live fewer years in good self-rated health than older non-migrants, in all three countries studied. These findings are consistent across the three countries, and with the results of previous studies in Europe (Solé-Auró and Crimmins 2008; Lanari and Bussini 2012). In a similar vein, while we may be unable to state with certainty that HLE₅₀ among females in England and Wales decreased over time, we can assert that the migrant health gaps in HLE₅₀ and HLE₅₀/LE₅₀ in England and Wales increased.

Finally, we classified residents of England and Wales who were born in other parts of the UK as western migrants. Since the migration trajectories of these internal migrants are likely to differ considerably from those of international migrants, we performed a sensitivity analysis in which we excluded Scottish and Northern Irish individuals from the dataset. This did not substantially alter the results, and the conclusions drawn from the comparison of HLE₅₀ and HLE₅₀/LE₅₀ between groups and over time remained the same (results not shown).

Using HLE as an indicator that combines mortality and health, our results consistently show that the HLE of older migrants, especially those of non-western origin, was lower than that of non-migrants. In most cases, these differences were mainly attributable to differences in self-rated health. Thus, our results are consistent with those of previous studies that merely used health as an outcome measure. These studies showed that compared to their non-migrant counterparts, older migrants in Europe have worse self-rated health, and more chronic conditions, limitations, and depression (Solé-Auró and Crimmins 2008; Lanari and Bussini 2012; Carnein et al. 2014). Poor health among migrants has often been explained by a range of individual and contextual factors, including economic difficulties, poor housing and working conditions, limited access to health care, cultural and language barriers, and social exclusion (Gushulak et al. 2010). The health-related lifestyles migrants adopt over their life course can affect their health at older ages; in addition, older migrants may be more prone than non-migrants to contracting diseases related to early life deprivation in their country of origin (Razum and Twardella 2002). The results also indicate, however, that the contribution of mortality to differences in HLE₅₀ between migrants and non-migrants was often small, and in certain cases, even contributed in the opposite direction. These findings are in line with the general migrant mortality paradox (Razum et al. 1998; Abraído-Lanza et al. 1999), or at least with weaker versions of it (Riosmena et al. 2013). The decomposition results illustrate how health and mortality do not necessarily follow a similar pattern, and hence the added value of using a combined measure (HLE) to study health and mortality disparities between migrants and non-migrants.

In England and Wales, the migrant HLE₅₀ inequalities decreased among males, but increased among females. However, the migrant HLE₅₀/LE₅₀ inequality gap in England and Wales increased for both sexes. The discrepancy among males can be attributed to the failure of improvements in HLE to keep pace with improvements in LE (morbidity expansion), especially among non-western migrants. Previous studies have also found that contemporary improvements in HLE in Europe tend to be slower than improvements in LE (Harper 2015). The increase in migrant HLE inequalities observed in England and Wales follows more general patterns, such as the increase in differences in HLE between local areas in Great Britain (Wohland et al. 2014) or between European countries (Fouweather et al. 2015). Economic hardship due to the economic crisis may explain why self-rated health did not improve over time (Clair et al. 2016), especially among (non-western) migrants, who are especially vulnerable to economic downturns given their fragile socio-economic position (International Organization for Migration 2010).

Our results also show, however, that migrant inequalities in both HLE₅₀ and in HLE₅₀/LE₅₀ in the Netherlands declined over time. In fact, only among non-western migrants in the Netherlands, improvements in HLE₅₀ over time were mainly driven by improvements in self-rated health, rather than by decreases in mortality. Although non-western migrants were the only group in the Netherlands for whom improvements in HLE were markedly faster than improvements in LE, there was also no morbidity expansion among western migrants or non-migrants either. A potential explanation for this finding is that unlike in most European countries, public spending on health in the Netherlands after the 2008 crisis was increased, and measures aimed at reducing pressure on highly congested medical services were implemented (Mladovsky et al. 2012).

Our analysis of health and mortality differences between older migrants and non-migrants across three countries over a 10-year period has generated some important new findings. Self-rated health, rather than mortality, seems to be the key explanatory factor beyond migrant inequalities in HLE, and their reduction over time. Interventions to reduce the health and mortality inequalities between older migrants and non-migrants should focus mainly on prevention rather than (palliative) treatment, and target the most disadvantaged groups, including non-western migrants.