Health status is influenced by a variety of determinants: genetics2, individual and contextual factors. Individual factors refer to social condition and individual choices, including living and working conditions, education level, socioeconomic status, integration in social life, health-related lifestyle behaviours (such as smoking, drinking, diet and physical activity), as well as the demand for health care services. Contextual factors refer to multiple surrounding dimensions, including national wealth, income inequality, health system features (e.g. supply of health care services, free access at point of care delivery, health prevention policy), social norms, and environment factors (e.g. transport and pollution).
All these determinants have an effect on health status, and interactions between them may influence health status more or less strongly. Understanding health inequalities relies heavily on the understanding of the relationships between socioeconomic factors, behaviours and health. The analysis framework of this thesis proposes to study social inequalities in behavioural risk factors and in health care utilisation as a means of addressing social inequalities in health. As shown below, this framework is consistent with G oss a s odel a d its e te sions.
2 This discussion leaves apart genetic factors, as they are not generally in the action target of governments. However it is worth noting that more and more attention is paid to the genomics, the science of genomic sequences, that is promising in the coming years to help to detect and prevent diseases such as cancers and cardio-vascular diseases.
2.1. Theoretical framework
Grossman (1972, 2000) developed an economic framework for the demand for health based on the human capital theory. In this framework, health is a capital which depends on the initial stock and depreciates over time, but can be increased with investment in health. Individuals are active producers of their health, buying market inputs (e.g. health care, food) and combining them with their own time to increase their utility. Education increases efficiency in the production of health since more educated people are in a better position to process health information, and make better investment in health.
G oss a s odel p o ides a theo eti al f a e o k fo aki g p edi tio s of health as a fu tio of education and socioeconomic status, which are positive determinants of the investments in health. Thus, G oss a s odel is a solid foundation for the study of inequality in health (Galama and van Kippersluis, 2013).
As investment in health is a key concept in this model, lifestyle behaviours and individual preferences play an important role in this theoretical framework. A number of studies confirm the impact of health-related behaviours on social inequalities in health (McGinnis and Foege, 1993; Contoyannis and Jones, 2004; Stringhini et al., 2010). However, unhealthy behaviours may not all contribute to determining health status to the same degree or in the same direction. While smoking contributes largely to the well-known gradient of social health inequalities, drinking behaviours may sometimes contrast.
Van Kippersluis and Galama (2013) study why the rich drink more but smoke less, and they propose a theory of health behaviours to explain why richer people engage more in moderate unhealthy behaviours and less in harmful behaviours3.
I G oss a s odel, edu atio a d so ioe o o i status a e o elated to health. This correlation has been widely validated in empirical studies. However, evidence for a causal relationship remains debated. The challenge is to identify whether the social gradient in health reflects a causal link from socioeconomic status to health, or a reverse causality from health to social outcomes. This question has been studied in the literature leading to mixed findings. Evidence goes in both directions, showing for example that health influences labour (Morris, 2007; Lundborg et al., 2010; Burton et al. 1998) and labour
3 Van Kippersluis and Galama (2013) assume that the decision to engage in unhealthy consumption is governed by the monetary cost of the good and the health cost related to the consumption of the good (i.e. value of health lost). They assume that wealth influences health behaviours via two competing effects: the direct wealth effect that increases the demand for (unhealthy) consumption goods; and the indirect health cost effect that decreases the demand for unhealthy consumption goods (since the
influences health status (Llena-Nozal, 2009; Robone et al. 2011). About the latter, the impact of labour on health status has been shown to be positive in some studies and negative in others, but a convergence in findings emerges, suggesting that the negative health impact of work is related to situations in which workers have essentially no control (no choice) over the amount of work they provide (Bassanini and Caroli, 2014).
When studying inequalities in health-related behaviours, one important dimension to consider is individual time preferences i.e. whether people value more short-term satisfaction rather than long-term consequences of their health behaviours. In particular, about health-related and addictive behaviours, individuals must often make the trade-off between immediate satisfaction of unhealthy goods consumption (e.g. food high in fat and sugar, tobacco, and alcohol) and future losses in health capital.
Economic models for addictive goods were originally introduced by Becker and Murphy (1988) with the rational addiction theory which assumes that the consumer is aware of the future consequences of addictive goods consumption and accounts for them when making consumption choices. This model relies on the idea that current preferences for addictive goods depend on past and anticipated consumption of that goods. The rational addiction theory finds support in empirical studies, in particular in relation to smoking (Chaloupka and Warner, 2000; Clark and Etilé, 2002).
Individual time preferences are correlated to education and socioeconomic status, with little evidence on the direction of causality. Individuals who discount the future less (i.e. who have a preference for future) invest more in education and engage more in healthy behaviours (Fuchs, 1982).
Similarly, less educated and poorer people discount the future more heavily than richer people (Becker and Mulligan, 1997). The interplay between time preferences, health behaviours, and education is therefore of importance for the study of social inequalities in health-related behaviours. Individual time preferences may affect the relationship between education and health by having a mediating role of social health inequalities, as suggested by empirical studies (van der Pol, 2011; Jusot and Khlat 2013).
2.2. Focus on social inequalities in health-related behaviours
Figure 1 illustrates the analysis framework of this thesis wherein social disparities in health outcomes results from direct and indirect pathways of social determinants. Tackling social inequalities in health can be achieved to some extent by addressing inequalities in behavioural risk factors and inequalities in health care utilisation.
Figure 1. Determinants of social inequalities in health
Source: Author.
Differences in morbidity and mortality may be directly related to living and working conditions (e.g.
type of occupation that may have inherent cancer risks), but they may also emerge from between-groups differences in behavioural risk factors (e.g. smoking, obesity, alcohol use) (arrow (a) in Figure 1) and differences in health care services utilisation (e.g. doctor consultations) (arrow (b)). Lifestyles and behavioural risk factors play an important role in the relationship between health and socioeconomic factors. They are often significantly influenced by education and socioeconomic status and, at the same time, they contribute to health and longevity by affecting the probability of developing a wide range of diseases (e.g. cardiovascular diseases, diabetes, cancers, musculoskeletal diseases, mental ill-health).
Similarly, access to health care is as important as lifestyle in the determination of social health inequalities. For example, higher-income people are shown to have better access to health care services, which translates into differences in health outcomes.
Thus, reducing social health inequalities depends not only on efforts directly made to improve health outcomes of the worst-off, but also efforts to reduce social inequalities in behavioural risk factors and health care utilisation. In addition to health-related behaviours, external factors may interact with and exacerbate or diminish social inequalities in health. For instance, there are potential interactions with contextual and environmental factors, such as health system characteristics (e.g. density of medical
Environment : External constraints i flue i g i di idual s behaviours, Heath system features, Social norms Health outcomes
Education / Socioeconomic
background
Health care utilisation Health-related
behavioural risk factors
(a) (b)
services, copayment system), social norms, transport and pollution. This aspect is further discussed in Chapter 4, with the analysis of health system characteristics as determinants of inequities in health care utilisation.