LIMITATIONS AND CHALLENGES OF HEALTH AND MIGRATION RESEARCH IN THE WORLD

This literature review supports the idea that social and spatial migration affects health. It affects the distribution of poor health and wellbeing, and people’s experience of these conditions.

However, migration research faces several difficulties and studies tend to show a range of results depending on the group observed and the comparison made. Moreover, moving can be beneficial or detrimental to health, depending on the nature of the move, the individual or group moving, and the origin and destination (Shaw, Dorling and Mitchel, 2002). The literature on migration and health often compares the patterns of migrant groups to the patterns of the host population and, in addition, to their non-migrant counterparts in the country of origin. The health status of migrants usually differs from that of the non-migrants and these differences provide an

opportunity to separate the influences of genetic and environmental factors on human health (McKay, Macintyre and Ellaway, 2003). The mortality and morbidity patterns of immigrants can be influenced by both their country of origin and their destination, and by the process of

migration itself (McKay, Macintyre and Ellaway, 2003). However, a positive and useful characteristic of migration is that it involves a concrete and particular change (spatial and or social mobility) that allows the observation of the effects of this change over time upon a large number of possible health outcomes (Shaw, Dorling and Mitchel, 2002). Describing these patterns can shed light on why the migration process, its causes and consequences, are so complex and difficult to analyse and interpret.

The main methodological limitations of research concerning migration and health are displayed in Table 3.4. Some of these limitations are common to broader issues of research on migration and have been presented in Chapter 2 (section 2.7). In addition, they are linked to the challenges of studying migration and health in the world and in Chile. Those are, at least, the following four:

1. Health is not considered a major issue for migrants in the world: Limited human and economic effort is addressed to this matter compared to other health problems or vulnerable groups. This can be observed, for example, in the limited number of publications related to migration and health (compared to biomedical publications, for instance). However, it should be a major issue as it involves human rights, a large proportion of migrants suffer the burden of several diseases, health problems move from one country to the other, there is lack of

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access to health care for immigrants, receiver populations also suffer, and issuer countries are losing health workers (EESC, 2007).

2. Very few countries collect information about migration and health: Many of the coding systems do not ask for the migrant status and some undocumented migrants would hide this information out of fear. There is a lack of differentiation between first generation immigrants and their descendants and how this is related to health. More information has appeared during recent years, but can be collected as or confused with ethnicity (EESC, 2007).

3. Migration affecting geographic differences in disease risk: Human migration can make it more difficult to detect geographic differences in disease risk because of the spatial diffusion of people originally exposed in a given geographic area (Rogerson and Han, 2002). As mentioned previously, health might affect migration through a range of possible processes and large-scale movement of people can also affect the geography of health, changing patterns of morbidity and mortality (Shaw, Dorling and Mitchel, 2002; Boyle, 2004).

Geographical studies of disease tend to focus on particular locations and contrast “long-term, native non-migrants with in-migrants” (Rogerson and Han, 2002), but data constraints often limit the alternative to develop better analysis.

4. Poor policy development from available data: Some European Union countries have adopted resettlement policies that stress geographical dispersal of minorities and migrants in order to achieve faster integration into mainstream society. There is little evidence as to whether this has been effective and the “isolation that follows can instead be highly detrimental to the mental health and social integration potential of newcomers” (Carballo, Divino and Zeric, 1998). Some authors discuss how many countries and employers still restrict migration to those who will be employed full-time and do not include close family members (Carballo, Divino and Zeric, 1998). Despite arguments for this from the receiving country, physical and mental implications of these policies deserve consideration. Moreover, even when family is accepted in the host country, families may continue to struggle. Work conditions and social isolation can lead to high risk for mental illness and other diseases for parents and children.

Programs to help social integration need urgent consideration (Carballo, Divino and Zeric, 1998).

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Table 3.4 Main methodological limitations of research concerning migration and health Methodological limitation Explanation

Most literature is descriptive and the best comparison group for immigrants is difficult to define (i.e. what is the best counterfactual)

Migrants can have better health status than the average for people in their country of origin, but might have worse health status than the population of the country they arrive in and their health may decrease over time. There is a possible bias when comparing different groups, as immigrants are different from the population of origin and the receiver society.

Most studies are cross-sectional No causal inference can be explored in cross-sectional studies. As reported by Niclas et al. (2007) some studies have found increased wellbeing among movers who had moved into areas with improved environmental housing quality. On the other hand, some people may have difficulties in adapting to a new area, such as creating

connections with neighbours, which may be detrimental to health. In addition, cross-sectional studiesdo not reflect the different latent periods that might be responsible for some of the associations (Barker, 1987). Besides, a specific migration effect must be separated from cohort effects (Holland, 2000; Kindig, 2002). The common

denominator in dealing with these types of bias is the requirement for longitudinal health data to reduce the risk of bias associated to cross-sectional studies.

Access to health care as a selection bias

Several barriers to access to health care among immigrants have been reported: language, costs, being undocumented, fear of discrimination, lack of accurate information (health system complexity), cultural differences about the conceptions of health and disease, and others (EESC, 2007). These might confound the prevalence of health indicators measured in the health care system between immigrants and the local population.

Confounding effect of short stays

Around 14 million people make a brief trip from developed countries to developing countries and a proportion of them return with a foreign disease. Controlling these risks and potential confounding effects in research is very complicated as tourism, short term and circular migration continues to grow (EESC, 2007).

Underestimation effect because of the presence of

undocumented people

There is a lack of information of health status of undocumented people who do not access the health systems because of their irregular situations (EESC, 2007). This might create an underestimation of the real severity of health problems among migrants, as they don’t appear in any system and are not willing to complete surveys.

“Place of birth” versus “place of residence” as a predictor of health outcomes

Much variation exists between migrant groups and that the disease patterns of immigrants are influenced by the country of origin and by the migration process (McKay et al., 2003). For example, Elford and colleagues (1990) found that place of residence is a more important determinant than place of birth, Osmond et al. (1990) found the opposite results, and Strachan and collaborators (1995) found that both were relevant (Rogerson and Han, 2002).

Migration as a cause of mental health outcomes or vice-versa?

The causal direction of the association between migration and mental illness is not straightforward. People tend not to move at random and their chance to travel is highly influenced by their social and health circumstances. Simultaneously, health can be modified over time, caused by the migration process (Shaw et al., 2002).

Choice and size of area borders Administrative areas may not be ecologically meaningful or natural (Pickett and Pearl, 2001). The use of smaller areas may lead to an increase in measurement error, but small areas will, at the same time, be more homogeneous in terms of their socioeconomic and other important characteristics (Niclas et al., 2007).

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3.5 EVIDENCE, CHALLENGES AND LIMITATIONS OF HEALTH AND MIGRATION