Models explaining the relationship between the SDH and health

Four main models have been developed in order to explain the relationship between the SDH and health. Those models are: (1) material/neo material models; (2) behavioural/cultural models;

(3) psychosocial models; and (4) the life-course approach (Bartley, 2007) (see Table 4.1). The following paragraphs will describe each of them in a brief narrative fashion. It should be noted that these models have been developed outside of Latin America and are based on research into health primarily in the UK, the US and other developed countries. However, some key variables of these models are available in the CASEN survey 2006, and will be explored as a first step towards an understanding of the transferability of these theoretical models into middle-income countries such as those in Latin America, especially Chile.

The CASEN survey includes measures of material household conditions. These are directly related to the effects of absolute poverty included in the materialist model and indirectly related to the effects of relative social position included in the psychosocial model. The CASEN survey also contains measures of socioeconomic status, including income, education and type of occupation, again related to the psychosocial model. Unfortunately, no data on individual health-risk behaviours are captured by the CASEN survey and will need to be explored in the future.

This thesis also includes measures of access to health care and use of health care services by international immigrants in Chile, which are not clearly displayed in these theoretical models and only partially tackled by the neo-materialist model, but might be a significant dimension to include in future adapted versions of these frameworks in Chile. The complexity of the Chilean health care system and the lack of universal coverage for every person living in the country will be described in detail in Chapter 8.

Table 4.1Main models developed to explain the relationship between SDH and health outcomes MAIN EXPLANATORY MODELS (Bartley, 2007)

Material Cultural/ behavioural Psycho-social

Influences Individual income less likely to drink alcohol moderately, abstain from smoking and take exercise in leisure time, etc.

Status, control, social support at work or at home, balance between effort and reward influence health through their impact in body functions

122 4.1.1.a) Material/Neo material models

Much of the evidence for the existence of material causes of health inequalities has come from different studies that showed that health is worse in people who live in poverty (e.g. Marmot et al., 1991; Mustard et al., 1997; Wolfson et al., 1993; Kaufman et al., 1998; Pappas et al., 1993;

Bartley, 2007). An impressive feature from several studies is that illness and mortality are not just high in the poor and average in the rest. Rather, illness and mortality show a gradient, that is to say a stepwise increase, with each step down the income ladder (Davey Smith et al., 1996a;

Davey Smith et al., 1996b). A large number of studies have tested the materialist model, most of them in developed countries. Both individual and household incomes have been found to be associated with mortality (Mustard et al., 1997; Kaufman et al., 1998) and life expectancy (Wolfson et al., 1993). Moreover, levels of analysis used in the past include the individual, neighbourhoods, regions, nations, amongst others, and have all shown a consistent income gradient with poorest health rates in those living in poverty compared to those who are wealthy.

As proposed by Bartley (2007), the materialist model can be easily understood, but is more complex than is observed on the surface. It is commonly accepted that the environment is the place where the body comes into contact with health hazards like damp, mould, fumes and dust, low temperatures, or hazardous places engendering disease and injury, and that those are

partially determined by household income (i.e. the ability to obtain adequate housing and keep it warm and clean, materialist model) or the existence of social policies providing minimum adequate housing to those who unable to afford it (i.e. public sources such as social benefits to those in poverty and to a lesser extent universal coverage for health care, neo materialist model) (Blane, Bartley and Davey Smith, 1998; Blane, Mitchel and Bartley, 2000; Doniach et al., 1975).

However, when trying to estimate the size of the effect of these types of material factors on health, they are not responsible for more than 25% of deaths (Bartley, 2007). On the one hand, methodological limitations, such as the recognition of the real causes of death among workers exposed to hazards, are a relevant issue. In addition, psycho-social and life-course perspectives need major consideration to complement the material or neo-material factors (developed to explain why countries with public subsidies have better health outcomes than those that don’t have social public support) (Bartley, 2007, Deaton and Lubotsky, 2003; Duncan, 1961; Fiscella and Franks, 1997; Mitchell, Blane and Bartley, 2002; Morris et al., 2002; Platt et al., 1989).

An extensive debate regarding the importance of the materialist/neo materialist model has been held in the past two decades, particularly in developed countries like the UK and the USA.

Currently, it is agreed that the materialist/neo materialist model is not as important as other

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explanatory models of health inequalities among developed countries, where absolute material poverty does not exist to a large extent (Lynch et al., 2001; Mackenbach, Looman and Kunst, 1993; Blane, Bartley and Davey Smith, 1998; Blane, Mitchel and Bartley, 2000; Martin, Platt and Hunt, 1987; Coburn, 2000; Davey Smith et al., 1996a; Davey Smith et al., 1996b). Within developed countries, it is the effect of relative poverty (as established when comparing different socioeconomic groups in a country or across similarly developed countries) that has the largest effect upon health inequalities (Wilkinson & Pickett, 2009; Wilkinson, 1996; Kawachi et al., 1997; Kennedy, Kawachi and Prothorwstith, 1996). In contrast, developing countries like Chile and others in the Latin American region have not tested the relative importance of a materialist model versus other models. Nonetheless, because of the early stage of their economic

development, they do face the existence of absolute poverty in a large proportion of their population (Roberts, 2002; Ortiz-Hernandez, Lopez-Moreno and Borges, 2007; De Almeida et al., 2003). For that reason, it is unclear the extent to which material factors might explain inequalities in health between socioeconomic groups. No study in Chile has yet analysed this hypothesis and I will explore the possible effect in the immigrant population and the Chilean-born in this thesis.

4.1.1.b) Behavioural/cultural models

Since the publication of the Black Report in the UK in 1986, “both individual research reports and official surveys have repeatedly documented persistent differences between social groups in various types of consumption and leisure activities that are related to health” (Bartley, 2007).

Major risk behaviours, like smoking, have displayed a clear socioeconomic gradient in different countries, meaning that the less advantaged the social class position, the more likely it is that a person will smoke. Similar findings have been reported by other authors (Bunton and Burrows, 1995; Cable, 1999; Cameron and Jones, 1985; Lantz et al., 2001; Lynch et al., 1997b; Stronks et al., 1997). Bartley (2007) has described two types of behavioural/ cultural model, the direct model and the indirect model.

The direct behavioural model rests on the assumption that people with less control over their employment circumstances, and with a lower socioeconomic position and income, are less capable of developing certain types of personal abilities and characteristics like IQ, coping skills or personal resilience. The direct behavioural model could be seen as a sub-type of the

behavioural/ cultural explanation, where the link between social position and behaviour is due to adverse personal characteristics (or the lack of good ones) that are independent of social status.

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However, people with favourable attributes, such as internal locus of control, may move up the social scale into more advantaged positions as a result of their mental capacities. The indirect model observes behaviour as a result of culture, defined as a complex whole that includes knowledge, beliefs, art, morals, laws, customs, and other capabilities and habits (Bartley, 2007).

Shared rules govern behaviours that are shaped by exposure to a certain social environment over the life course. Very few studies have appeared which acknowledge cultural differences between social classes causing social differences in health. However, what has been developed so far tends to support the relevance of cultural circumstances affecting social differences in health (Bartley, 2007; Shewry et al., 1992; Chandola, 1998; Sacker et al., 2000).

In the context of migration, research has suggested that some protective individual behaviours disappear after immigrants arrive in the foreign country, and that individual health-risk behaviours that are prevalent in the host society tend to be acquired by first and second generation immigrants over time, through a process of acculturation. Acculturation has been defined as an individual’s process of learning about and adoption of the receiving society’s cultural norms, as well as the degree to which the person maintains his or her cultural heritage (Kohatsu, 2005; Phinney, 2003; Schwartz et al., 2010; Schwartz et al., 2011). The concept of assimilation is particularly defined as immigrants becoming more similar to the host society, and the concept of enculturation is defined as immigrants maintaining their social norms and cultural traditions in the foreign country (Warner, Fischbein and Krebs, 2010). Acculturation issues are salient not only for first-generation immigrants but also for those of the second generation.

Indeed, the heritage culture often predominates in the home (and the local community) for individuals from immigrant families. As a result, second generation immigrants are still likely to be socialized toward the practices, values, and identifications typical of their heritage cultures (enculturation process) (Schwartz et al., 2010b; Portes & Rumbaut, 2001). These changes, and the interaction between acculturation/assimilation and enculturation processes among

immigrants over time, could go a long way to explaining the gradual deterioration of their health (i.e. the disappearance of the healthy migrant effect mentioned in Chapter 3).

International evidence regarding different migrant groups in different settings supports the phenomenon described above (e.g. Acevedo-Garcia et al., 2005; Jeltova, Fish and Revenson, 2005; Warner, Fischbein and Krebs, 2010; Toppelberg & Collins, 2010; Chun, Chelsa and Kwan, 2011; Arcia, Skinner and Bailey, 2001; Gordon-Larsen et al., 2003; Stoddard, 2009). No research in this topic has been conducted among immigrants in Chile, but recent evidence reports an increased prevalence of individual health-risk behaviours in the Chilean population,

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especially among those of low socioeconomic status (with the exception of tobacco) (Encuesta Nacional de Salud, National Health Survey, ENS, 2010). Moreover, an urgent need to

incorporate a broader understanding of the social inequalities that underlie this phenomenon, due to its direct policy implications in Chile, has been also identified (Cabieses, Zitko and Espinoza, 2011).