Social determinants of health

Social determinants of health are the economic and social conditions under which people live which determine their health. Virtually all major diseases are primarily determined by a network of interacting exposures that increase or decrease the risk for the disease. This is particularly the case for cardiovascular disease and type II diabetes. And these conditions are a result of social, economic, and political forces.

Factors

Social determinants of health have been recognized by several health organizations such as the Public Health Agency of Canada and the World Health Organization to greatly influence collective and personal well-being. A list of determinants of health — only some of which are social determinants — is below:

1. Income and social status
Social support networks
3. Education and literacy, i.e. health literacy
4. Employment/Working conditions
Social environments
Physical environments
Life skills
8. Personal health practices and coping skills
9. Healthy child development
10. Biology and genetic endowment
Health services
Gender
Culture

The term social determinants of health grew out of the search by researchers to identify the specific exposures by which members of different socio-economic groups come to experience varying degrees of health and illness. While it was well documented that individuals in various socio-economic groups experienced differing health outcomes, the specific factors and means by which these factors led to illness remained to be identified. Overviews of the concept, recent findings, and an analysis of emerging issues are available. All these formulation share a concern with factors beyond those of biomedical and behavioural risk.

The SDOH National Conference list (see Raphael, below) is unique in that it specifically focuses on the public policy environment (e.g., income and its distribution) rather than characteristics associated with individuals (e.g. income and social status). These 11 social determinants of health are:

1. Aboriginal status
2. early life
3. education
4. employment and working conditions
5. food security
6. gender
7. health care services
8. housing
9. income and its distribution
10. social safety net
11. social exclusion
12. unemployment and employment security.

Background

The modern study of the social determinants of health can be said to have begun with the writings of Rudolph Virchow and Friedrich Engels during the mid 19th century. Virchow's Report on the Typhus Epidemic in Upper Silesia (Virchow 1848/1985) and Engels' The Condition of the Working Class in England (Engels 1845/1987) not only made the explicit link between living conditions and health but also explored the political and economic structures that create inequalities in the living conditions which lead to health inequalities. Over 150 years ago Virchow stated: Do we not always find the diseases of the populace traceable to defects in society? (Virchow, 1849/1985) p.117, while Engels noted: That a class which lives under the conditions already sketched and is so ill-provided with the most necessary means of subsistence, cannot be healthy and can reach no advanced age is self-evident (Engels, 1845/1987) p. 128).

More recent developments

More recently, international interest in the social determinants of health led to the World Health Organization;s creating a Commission on the Social Determinants of Health (World Health Organization, 2008). Its final report Closing the Gap in a Generation: Health Equity through Action on the Social Determinants of Health succinctly summarizes the current state of knowledge (Box 1).

• Box 1: The Commission calls for closing the health gap in a generation

Social justice is a matter of life and death. It affects the way people live, their consequent chance of illness, and their risk of premature death. We watch in wonder as life expectancy and good health continue to increase in parts of the world and in alarm as they fail to improve in others. A girl born today can expect to live for more than 80 years if she is born in some countries – but less than 45 years if she is born in others. Within countries there are dramatic differences in health that are closely linked with degrees of social disadvantage.

These inequities in health, avoidable health inequalities, arise because of the circumstances in which people grow, live, work, and age, and the systems put in place to deal with illness. The conditions in which people live and die are, in turn, shaped by political, social, and economic forces.

Social and economic policies have a determining impact on whether a child can grow and develop to its full potential and live a flourishing life, or whether its life will be blighted. Increasingly the nature of the health problems rich and poor countries have to solve are converging. The development of a society, rich or poor, can be judged by the quality of its population’s health, how fairly health is distributed across the social spectrum, and the degree of protection provided from disadvantage as a result of ill-health.

In the spirit of social justice, the Commission on Social Determinants of Health was set up by the World Health Organization (WHO) in 2005 to marshal the evidence on what can be done to promote health equity, and to foster a global movement to achieve it.

As the Commission has done its work, several countries and agencies have become partners seeking to frame policies and programmes, across the whole of society, that influence the social determinants of health and improve health equity. These countries and partners are in the forefront of a global movement.

The Commission calls on the WHO and all governments to lead global action on the social determinants of health with the aim of achieving health equity. It is essential that governments, civil society, WHO, and other global organizations now come together in taking action to improve the lives of the world’s citizens. Achieving health equity within a generation is achievable, it is the right thing to do, and now is the right time to do it.

Source: Commission on the Social Determinants of Health. (2008). Closing the Gap in a Generation: Health Equity through Action on the Social Determinants of Health. Geneva: World Health Organization.

Canada's role

Canada has been a leader in developing social determinants of health concepts (Evans, Barer, & Marmor, 1994; Health Canada, 2001; Restrepo, 2000). But Canada has been rather less successful than other wealthy nations in seeing these concepts put into action (Canadian Population Health Initiative, 2002; Collins & Hayes, 2007; Raphael, 2007a) . Instead, the application of these concepts in the service of health is well established in many European nations where it has been integrated into development and application of public policy (Mackenbach & Bakker, 2002). In Canada however, the approach remains subordinate to traditional medical and behavioural paradigms of health, illness, and health care.

What are social determinants of health?

The term “social determinants of health” grew out of researchers' search for the specific mechanisms by which members of different socio-economic groups come to experience varying degrees of health and illness (Graham, 2004; Tarlov, 1996). Everywhere, individuals of different socio-economic status show profoundly different levels of health and incidence of disease (Raphael, 2008d; Wilkinson & Marmot, 2003).

Another stimulus to investigating social determinants of health was the finding of national differences in population health. For example, the health status of Americans—using indicators such as life expectancy, infant mortality, and death by childhood injury rates—compares unfavourably to citizens in most industrialized wealthy nations (Navarro et al., 2004). In contrast, the health status of Scandinavians is generally superior to that seen in most nations (Burstrom, Diderichsen, Ostlin, & Ostergren, 2002). It was hypothesized that perhaps the same factors that explain health differences among groups within nations could also explain differences among national populations.

A variety of approaches to the social determinants of health exist and all of these are concerned with the organization and distribution of economic and social resources among the population. The Ottawa Charter for Health Promotion identifies the prerequisites for health as peace, shelter, education, food, income, a stable ecosystem, sustainable resources, social justice, and equity (World Health Organization, 1986). Health Canada outlines various determinants of health—most of which are social determinants—of income and social status, social support networks, education, employment and working conditions, physical and social environments, biology and genetic endowment, personal health practices and coping skills, healthy child development, gender, culture, and health services (Health Canada, 1998).

A British working group charged with the specific task of identifying social determinants of health named the social (class health) gradient, stress, early life, social exclusion, work, unemployment, social support, addiction, food, and transport (Wilkinson & Marmot, 2003). And the U.S. Centers for Disease Control and Prevention highlight social determinants of health of socioeconomic status, transportation, housing, access to services, discrimination by social grouping (e.g., race, gender, or class), and social or environmental stressors (Centers for Disease Control and Prevention, 2005).

Canadian workers synthesized these formulations to identify 12 key social determinants of health: Aboriginal status, early life, education, employment and working conditions, food security, gender, health care services, housing, income and its distribution, social safety net, social exclusion, and unemployment and employment security (Raphael, 2008b). These determinants are especially relevant to understanding and improving the health of Canadians. Evidence indicates that the health-related effects of each and every one of these factors equals or exceeds the influence of the so-called “lifestyle” or behavioural risk factors such as tobacco and alcohol use, diet, and physical activity (Raphael, 2008d), a conclusion stated as early as the mid 1970s (Marmot & Mustard, 1994; Marmot, Rose, Shipley, & Hamilton, 1978).

What is the evidence concerning the social determinants of health?

Research findings that examine the importance of the social determinants of health provide insights into: (a) the general improvement in health among citizens in developed nations over the past 100 years; (b) the health inequalities observed among populations within nations; and (c) differences in overall national health among both developed (e.g., between Sweden versus Canada versus the USA) and developing nations (e.g., between Cuba versus Argentina versus Brazil).

The social determinants of improved health among Canadians since 1900

Profound improvements in health status have occurred in industrialized nations such as Canada since 1900. It has been hypothesized that access to improved medical care is responsible for these differences, but best estimates are that only 10–15 percent of increased longevity since 1900 in wealthy industrialized nations is due to improved health care (McKinlay & McKinlay, 1987). As one illustration, the advent of vaccines and medical treatments are usually held responsible for the profound declines in mortality from infectious diseases in Canada since 1900. But by the time vaccines for diseases such as measles, influenza, and polio and treatments for scarlet fever, typhoid, and diphtheria appeared, dramatic declines in mortality had already occurred (McKinlay & McKinlay, 1987).

Improvements in behaviour (e.g., reductions in tobacco use, changes in diet, increased exercise, etc.) have also been hypothesized as responsible for improved longevity, but most analysts conclude that improvements in health are due to the improving material conditions of everyday life experienced by Canadians since 1900 (McKeown, 1976; McKeown & Record, 1975). These improvements occurred in the areas of early childhood, education, food processing and availability, health and social services, housing, employment security and working conditions and every other social determinant of health.

The social determinants of health inequalities among Canadians

Despite dramatic improvements in health in general, significant inequalities in health among Canadians persist (Canadian Population Health Initiative, 2004, 2008; Health Canada, 1999; Wilkins, Berthelot, & Ng, 2002). Access to essential medical procedures is guaranteed by Medicare in Canada. Nevertheless, access to care issues are common (McGibbon, 2008) and this is particularly the case in regards to required prescription medicines where income is a strong determinant of such access (Raphael, 2007b). It is believed however that health care issues account for a relatively small proportion of health status differences that exist among Canadians (Siddiqi & Hertzman, 2007). As for differences in health behaviours (e.g., tobacco and alcohol use, diet, and physical activity, etc.), studies from as early as the mid 1970s—reinforced by many more studies since then—find their impact upon health to be less important than social determinants of health such as income and other social determinants of health (Marmot, Shipley, Brunner, & Hemingway, 2001; Marmot et al., 1978; Nettleton, 1997; Raphael, 2007d).

Instead, evidence indicates that health differences among Canadians result primarily from experiences of qualitatively different living conditions associated with the social determinants of health. As just one example, consider the magnitude of differences in health that are related to the social determinant of health of income. Income is especially important as it serves as a marker of different experiences with many social determinants of health (Raphael et al., 2004). Income is a determinant of health in itself, but it is also a determinant of the quality of early life, education, employment and working conditions, and food security. Income also is a determinant of the quality of housing, need for a social safety net, the experience of social exclusion, and the experience of unemployment and employment insecurity across the life span. Also, a key aspect of Aboriginal life and the experience of women in Canada is their greater likelihood of living under conditions of low income (Raphael, 2007e).

Income is a prime determinant of Canadians’ premature years of life lost and premature mortality from a range of diseases (Raphael et al., 2006; Raphael et al., 2004). Numerous studies indicate that income levels during early childhood, adolescence, and adulthood are all independent predictors of who develops and eventually succumbs to disease (Benzeval, Dilnot, Judge, & Taylor, 2001; Benzeval & Judge, 2001; Davey Smith, 2003; Judge & Paterson, 2002).

In Canada almost a quarter of excess premature years of life lost (mortality prior to age 75) can be attributed to income differences among Canadians (Wilkins et al., 2002). These calculations are obtained by using the mortality in the wealthiest quintile of urban neighbourhoods as a baseline and considering all deaths above that level to be “excess” related to income differences. These analyses indicate that 23% of premature years of life lost to Canadians can be accounted for by differences existing between wealthy and other Canadians (Wilkins et al., 2002).

What are the diseases that differentially kill people of varying income levels? Income-related premature years of life lost can be correlated with death certificate cause of death (Wilkins et al., 2002). Among the not-wealthy, mortality by heart disease and stroke are especially related to income differences. Importantly, premature death by injuries, cancers, infectious disease, and diabetes are also all strongly related to not being wealthy in Canada. These rates are especially high among the least well-off Canadians,

In 2002, Statistics Canada examined the predictors of life expectancy, disability-free life expectancy, and the presence of fair or poor health among residents of 136 regions across Canada (Shields & Tremblay, 2002). The predictors included socio-demographic factors (proportion of Aboriginal population, proportion of visible minority population, unemployment rate, population size, percentage of population aged 65 or over, average income, and average number of years of schooling). Also placed into the analysis were daily smoking rate, obesity rate, infrequent exercise rate, heavy drinking rate, high stress rate, and depression rate.

Consistent with most other research, behavioural risk factors were rather weak predictors of health status as compared to socio-economic and demographic measures of which income is a major component (Benzeval et al., 2001; Lantz et al., 1998; Roux, Merkin, & Arnett, 2001). For life expectancy, the socio-demographic measures predicted 56% of variation (total variation is 100%) among Canadian communities. Daily smoking rate added only 8% more predictive power, obesity rate only another 1%, and exercise rate nothing at all! For disability-free life expectancy, socio-demographics predicted 32% of variation among communities, and daily smoking rated added only another 6% predictive power, obesity rate another 5%, and exercise rate another 3%. Differences among Canadians communities in numbers of residents reporting poor or fair health were related to socio-demographics (25% predictive power) with smoking rate adding 6%, obesity rate adding 10%, and exercise rate adding 3% predictive power.

Income-related effects are seen therefore in greater incidence and mortality from just about every affliction that Canadians experience. This is especially the case for chronic diseases. Incidence of, and mortality from, heart disease and stroke, and adult-onset or type 2 diabetes are especially good examples of the importance of the social determinants of health (Raphael, Anstice, & Raine, 2003; Raphael & Farrell, 2002).

While governments, medical researchers, and public health workers emphasize the importance of traditional adult risk factors (e.g., cholesterol levels, diet, physical activity, and tobacco and alcohol use), it is well established that these are relatively poor predictors of heart disease, stroke, and type 2 diabetes rates among populations (Chaufan, 2008; Davey Smith, Ben-Shlomo, & Lynch, 2002; Lawlor, Ebrahim, & Smith, 2002). The factors making a difference are living under conditions of material deprivation as children and adults, stress associated with such conditions, and the adoption of health threatening behaviours as means of coping with these difficult circumstances (Benzeval, Judge, & Whitehead, 1995). In fact, difficult living circumstances during childhood are especially good predictors of these diseases (Barker, Osmond, & Simmonds, 1989; Davey Smith & Hart, 2002; Eriksson et al., 1999; Eriksson, Forsen, Tuomilehto, Osmond, & Barker, 2001).

In addition to predicting adult incidence and death from disease, income differences — and the other social determinants of health related to income — are also related to the health of Canadian children and youth. Canadian children living in low-income families are more likely to experience greater incidence of a variety of illnesses, hospital stays, accidental injuries, mental health problems, lower school achievement and early drop-out, family violence and child abuse, among others (Canadian Institute on Children's Health, 2000). In fact, low-income children show higher incidences of just about any health-, social-, or education-related problem, however defined. These differences in problem incidence occur across the income range but are most concentrated among low-income children (Ross & Roberts, 1999; Ross, Roberts, & Scott, 2000; Willms, 2002).

One way to think about the different approaches to the determinants of health is presented in Box 2. In one approach the focus is on so-called lifestyle choices. In the other there is a concern with the social determinants of health.

• Box 2: Which tips for better health are more consistent with research evidence?

The messages given to the public by governments and health workers are influenced by the ways in which health issues are understood. Contrast the two sets of messages provided below. The first set assumes individuals can control the factors that determine their health. The second set assumes the most important determinants of health are beyond the control of most individuals. Which set of tips is most consistent with the evidence provided in this book?

The traditional 10 Tips for Better Health

• 1. Don't smoke. If you can, stop. If you can't, cut down.
• 2. Follow a balanced diet with plenty of fruit and vegetables.
• 3. Keep physically active.
• 4. Manage stress by, for example, talking things through and making time to relax.
• 5. If you drink alcohol, do so in moderation.
• 6. Cover up in the sun, and protect children from sunburn.
• 7. Practice safer sex.
• 8. Take up cancer-screening opportunities.
• 9. Be safe on the roads: follow the Highway Code.
• 10. Learn the First Aid ABCs: airways, breathing, circulation.

Source: L. Donaldson, Ten Tips for Better Health (London: Stationary Office, 1999).

The social determinants 10 Tips for Better Health

• 1. Don't be poor. If you can, stop. If you can't, try not to be poor for long.
• 2. Don't have poor parents.
• 3. Own a car.
• 4. Don't work in a stressful, low-paid manual job.
• 5. Don't live in damp, low-quality housing.
• 6. Be able to afford to go on a foreign holiday and sunbathe.
• 7. Practice not losing your job and don't become unemployed.
• 8. Take up all benefits you are entitled to, if you are unemployed, retired or sick or disabled.
• 9. Don't live next to a busy major road or near a polluting factory.
• 10. Learn how to fill in the complex housing benefit/asylum application forms before you become homeless and destitute.

Source: D. Gordon, Ten Tips for Better Health, 1999. Message posted on the Spirit of 1848 Listserv.

The social determinants of health differences between nations

Profound differences in overall health status exist between developed and developing nations. Much of this has to do with the lack of the basic necessities of life (food, water, sanitation, primary health care, etc.) common to developing nations. Yet among developed nations such as Canada, less profound but still highly significant differences in health status indicators such as life expectancy, infant mortality, incidence of disease, and death from injuries exist (Organisation for Economic Cooperation and Development, 2007). An excellent example is comparison of health status differences and the hypothesized social determinants of these health status differences among Canada, the United States, and Sweden.

Scholarship has noted that the USA takes an especially laissez-faire approach to providing various forms of security (employment, food, income, and housing) and health and social services while Sweden’s welfare state makes extraordinary efforts to provide security and services (Burstrom et al., 2002; Raphael & Bryant, 2006). The sources of these differences in public policy appear to be in differing commitments to citizen support informed by the political ideologies of governing parties within each nation (Bambra, 2004; Navarro & Shi, 2002).

Emerging scholarship is specifically focused on how national approaches to security provision to citizens influence health by shaping the quality of numerous social determinants of health. Nations such as Sweden whose policies reduce unemployment, minimize income and wealth inequality, and address numerous social determinants of health show evidence of improved population health using indicators such as infant mortality and life expectancy (Diderichsen, Whitehead, Burstrom, & Aberg, 2001). At the other end, nations with minimal commitments to such efforts such as the United States show rather worse indicators of population health (Raphael, 2008c).

Finally, poverty is an especially important indicator of how various social determinants of health combine to influence health. Using child – that is family – poverty rates as an important social determinants of both child and eventual health, Canada does not fare well in relation to European nations.

Mechanisms and pathways by which social determinants of health influence health

To secure attention to the social determinants of health and build support for their strengthening, it is important to understand how social determinants of health come to influence health and cause disease. How do social determinants of health “get under the skin” to influence health? The very influential UK Black and The Health Divide reports considered two primary mechanisms for understanding this process: cultural/ behavioural and materialist/structuralist (Townsend, Davidson, & Whitehead, 1992).

The cultural/behavioural explanation was that individuals' behavioural choices (e.g., tobacco and alcohol use, diet, physical activity, etc.) were responsible for their developing and dying from a variety of diseases. Both the Black and Health divide reports however, showed that behavioural choices are heavily structured by one’s material conditions of life. And—consistent with mounting evidence—these behavioural risk factors account for a relatively small proportion of variation in the incidence and death from various diseases. The materialist/structuralist explanation emphasizes the material conditions under which people live their lives. These conditions include availability of resources to access the amenities of life, working conditions, and quality of available food and housing among others.

The author of the Health Divide concluded: The weight of evidence continues to point to explanations which suggest that socio-economic circumstances play the major part in subsequent health differences (Whitehead, 1992). Despite this conclusion and increasing evidence in favour of this view, much of the Canadian public discourse on health and disease remains focused on “life-style” approaches to disease prevention (Raphael, 2008a).

These materialist/structuralist conceptualizations have been refined such that analysis is now focused upon three frameworks by which social determinants of health come to influence health (Bartley, 2003). These frameworks are: (a) materialist; (b) neo-materialist; and (c) psychosocial comparison. The materialist explanation is about how living conditions – and the social determinants of health that constitute these living conditions -- shape health. The neo-materialist explanation extends the materialist analysis by asking how these living conditions come about. The psychosocial comparison explanation considers whether people compare themselves to others and how these comparisons affect health and wellbeing.

Materialist approach: conditions of living as determinants of health

In this argument individuals experience varying degrees of positive and negative exposures over their lives that accumulate to produce adult health outcomes (Shaw, Dorling, Gordon, & Smith, 1999). Overall wealth of nations is a strong indicator of population health. But within nations, socio-economic position is a powerful predictor of health as it is an indicator of material advantage or disadvantage over the lifespan (Graham, 2007). Material conditions of life determine health by influencing the quality of individual development, family life and interaction, and community environments. Material conditions of life lead to differing likelihood of physical (infections, malnutrition, chronic disease, and injuries), developmental (delayed or impaired cognitive, personality, and social development), educational (learning disabilities, poor learning, early school leaving), and social (socialization, preparation for work, and family life) problems (Raphael, 2007c; Shaw et al., 1999).

Material conditions of life also lead to differences in psychosocial stress (Brunner & Marmot, 2006). The fight-or-flight reaction—chronically elicited in response to threats such as income, housing, and food insecurity, among others—weakens the immune system, leads to increased insulin resistance, greater incidence of lipid and clotting disorders, and other biomedical insults that are precursors to adult disease.

Adoption of health-threatening behaviours is a response to material deprivation and stress (Jarvis & Wardle, 2003). Environments determine whether individuals take up tobacco, use alcohol, experience poor diets, and have low levels of physical activity. Tobacco and excessive alcohol use, and carbohydrate-dense diets are also means of coping with difficult circumstances (Wilkinson, 1996). Materialist arguments help us understand the sources of health inequalities among individuals and nations and the role played by the social determinants of health.

Neo-materialist approach: conditions of living and social infrastructure as determinants of health

Exposures to the material conditions of life are important for health, but why are these material conditions so unequally distributed among the Canadian population but less so elsewhere? (Graham, 2004). The neo-materialist approach is concerned with how nations, regions, and cities differ on how economic and other resources are distributed among the population (Lynch, Smith, Kaplan, & House, 2000). Some jurisdictions have more equalitarian distribution of resources such that there are fewer poor people and the gaps that exist among the population in their exposures to the social determinants of health is narrower than places where there are more poor people and the gaps among the population are greater.

In the USA, states and cities with more unequal distributions of income have more low-income people and greater income gaps between rich and poor. They invest less in public infrastructure such as education, health and social services, health insurance, supports for the unemployed and those with disabilities, and spend less on education and libraries. All of these issues contribute to the quality of the social determinants of health to which people are exposed. Such unequal jurisdictions have much poorer health profiles than more equalitarian places (Kaplan, Pamuk, Lynch, Cohen, & Balfour, 1996; Lynch et al., 1998).

Canada has a smaller proportion of lower-income people, a smaller gap between rich and poor, and spends relatively more on public infrastructure than the U.S. (Ross, Wolfson et al., 2000). Not surprisingly, Canadians enjoy better health than Americans as measured by infant mortality rates, life expectancy, and death rates from childhood injuries (Siddiqi & Hertzman, 2007). Neither nation does as well as Sweden where distribution of resources is much more equalitarian, low-income rates are very low, and health indicators are among the best in the world.

The neo-materialist view therefore, directs attention to both the effects of living conditions – the social determinants of health -- on individuals' health and the societal factors that determine the quality of the distribution of these social determinants of health. How a society decides to distribute resources among citizens is especially important.

Social comparison approach: hierarchy and social distance as determinants of health

The argument here is that the social determinants of health play their role through citizens’ interpretations of their standings in the social hierarchy (Kawachi & Kennedy, 2002; Tarlov, 1996). There are two mechanisms by which this occurs.

At the individual level, the perception and experience of one’s status in unequal societies lead to stress and poor health. Comparing their status, possessions, and other life circumstances to those better-off than themselves, individuals experience feelings of shame, worthlessness, and envy that have psychobiological effects upon health. These processes involve direct disease-producing effects upon neuro-endocrine, autonomic and metabolic, and immune systems (Brunner & Marmot, 2006). These comparisons can also lead to attempts to alleviate such feelings by overspending, taking on additional employment that threaten health, and adopting health-threatening coping behaviours such as overeating and using alcohol and tobacco Kawachi & Kennedy, 2002).

At the communal level, widening and strengthening of hierarchy weakens social cohesion, a determinant of health (Kawachi & Kennedy, 1997). Individuals become more distrusting and suspicious of others with direct stress-related effects on the body. Such attitudes can also weaken support for communal structures such as public education, health, and social programs. An exaggerated desire for tax reductions on the part of the public can weaken public infrastructure.

This approach directs attention to the psychosocial effects of public policies that weaken the social determinants of health. But these effects may be secondary to how societies distribute material resources and provide security to its citizens – processes described in the materialist and neo-materialist approaches. Material aspects may be paramount and the stresses associated with deprivation simply add to the toll on individuals’ bodies.

The importance of a life-course perspective

Traditional approaches to health and disease prevention have a distinctly non-historical here-and-now emphasis. Usually adults, and increasingly adolescents and youth are urged to adopt “healthy lifestyles” as a means of preventing the development of chronic diseases such as heart disease and diabetes, among others (Chronic Disease Prevention Alliance of Canada, 2003; Health Canada, 2003). In contrast to these approaches, life-course approaches emphasize the accumulated effects of experience across the life span in understanding the maintenance of health and the onset of disease. It has been argued:

“The prevailing aetiological model for adult disease which emphasizes adult risk factors, particularly aspects of adult life style, has been challenged in recent years by research that has shown that poor growth and development and adverse early environmental conditions are associated with an increased risk of adult chronic disease (Kuh & Ben-Shilmo, 1997) p. 3”

More specifically, it is apparent that the economic and social conditions—the social determinants of health—under which individuals live their lives have a cumulative effect upon the probability of developing any number of diseases. This has been repeatedly demonstrated in longitudinal studies—the U.S. National Longitudinal Survey, the West of Scotland Collaborative Study, Norwegian and Finnish linked data—which follow individuals across their lives (Blane, 2006). This has been most clearly demonstrated in the case of heart disease and stroke (Raphael & Farrell, 2002). And most recently, studies into the childhood and adulthood antecedents of adult-onset diabetes show how adverse economic and social conditions across the life span predispose individuals to this disorder (Lawlor et al., 2002; Raphael et al., 2003)

A recent volume brings together some of the important work concerning the importance of a life-course perspective for understanding the importance of social determinants (Davey Smith, 2003). Adopting a life-course perspective directs attention to how social determinants of health operate at every level of development—early childhood, childhood, adolescence, and adulthood—to both immediately influence health as well as provide the basis for health or illness during later stages of the life course.

Hertzman outlines three health effects that have relevance for a life-course perspective (Hertzman, 2000). Latent effects are biological or developmental early life experiences that influence health later in life. Low birth weight, for instance, is a reliable predictor of incidence of cardiovascular disease and adult-onset diabetes in later life. Experience of nutritional deprivation during childhood has lasting health effects.

Pathway effects are experiences that set individuals onto trajectories that influence health, well-being, and competence over the life course. As one example, children who enter school with delayed vocabulary are set upon a path that leads to lower educational expectations, poor employment prospects, and greater likelihood of illness and disease across the lifespan. Deprivation associated with poor-quality neighbourhoods, schools, and housing sets children off on paths that are not conducive to health and well-being.

Cumulative effects are the accumulation of advantage or disadvantage over time that manifests itself in poor health. These involve the combination of latent and pathways effects. Adopting a life-course perspective directs attention to how social determinants of health operate at every level of development—early childhood, childhood, adolescence, and adulthood—to both immediately influence health and provide the basis for health or illness later in life.

The importance of public policy and policy environments

Much social determinants of health research simply focuses on determining the relationship between a social determinant of health and health status. So a researcher may document that lower income is associated with adverse health outcomes among parents and their children. Or a researcher may demonstrate that food insecurity is related to poor health status among parents and children as is living in crowded housing, and so on. This is what is termed a depoliticized approach in that it says little about how these poor-quality social determinants of health come about (Raphael & Bryant, 2002).

Social determinants of health do not exist in a vacuum. Their quality and availability to the population are usually a result of public policy decisions made by governing authorities. As one example, consider the social determinant of health of early life. Early life is shaped by availability of sufficient material resources that assure adequate educational opportunities, food and housing among others. Much of this has to do with the employment security and the quality of working conditions and wages. The availability of quality, regulated childcare is an especially important policy option in support of early life (Esping-Andersen, 2002). These are not issues that usually come under individual control. A policy-oriented approach places such findings within a broader policy context.

Yet it is not uncommon to see governmental and other authorities individualize these issues. Governments may choose to understand early life as being primarily about parental behaviours towards their children. They then focus upon promoting better parenting, assist in having parents read to their children, or urge schools to foster exercise among children rather than raising the amount of financial or housing resources available to families. Indeed, for every social determinant of health, an individualized manifestation of each is available. There is little evidence to suggest the efficacy of such approaches in improving the health status of those most vulnerable to illness in the absence of efforts to modify their adverse living conditions (Raphael, 2001).

Politics, political ideology, and the social determinants of health

Considering the evidence of the importance of the social determinants of health, how can we explain why certain nations take up this information and apply it in the formulation of public policy while others do not? Another way of considering this issue is inquire as to why there is such a gap between knowledge and action on the social determinants of health in Canada? One way to think about this is to consider the idea of the welfare state and the political ideologies that shape its form in Canada and elsewhere. The concept of the welfare state is about the extent to which governments – or the state – use their power to provide citizens with the means to live secure and satisfying lives (see Coburn, this volume). Every developed nation has some form of the welfare state. Important questions are: a) How developed is this welfare state? and b) What are the implications of the welfare state for the social determinants of health?

Two literatures inform this analysis. The first concerns the three forms of the modern welfare state. Esping-Andersen identifies three distinct clusters of welfare regimes among wealthy developed nations: Social Democratic (e.g., Sweden, Norway, Denmark, and Finland), Liberal (USA, UK, Canada, Ireland), and Conservative (France, Germany, Netherlands, and Belgium, among others) (Esping-Andersen, 1990, 1999). There is high government intervention and strong welfare systems in the social democratic countries and rather less in the liberal. Conservative nations fall midway between these others in service provision and citizen supports.

Social democratic nations have very well developed welfare states that provide a wide range of universal and generous benefits. They expend more of national wealth to supports and services. They are proactive in developing labour, family-friendly, and gender equity supporting policies. Liberal nations spend rather less on supports and services. They offer modest universal transfers and modest social-insurance plans. Benefits are provided primarily through means-tested assistance whereby these benefits are only provided to the least well-off. How do these forms of the welfare state come about? How do they shape the social determinants of health?

Navarro and colleagues provide empirical support for the hypotheses that the social determinants of health and health status outcomes are of higher quality in the social democratic rather than the liberal nations (Navarro, 2004; Navarro et al., 2004). Some of these indicators are spending on supports and services, equitable distribution of income, and wealth and availability of services in support of families and individuals. Health indicators include life expectancy and infant mortality.

Could this general approach to welfare provision shape Canadian receptivity to the concepts developed in this volume? And if so, what can be done to improve receptivity to and implementation of these concepts? The final chapter of this volume revisits these issues.

A particularly important issue that is emerging is whether any particular analysis of social determinants of health is de-politicized or not. A de-politicized approach is one that fails to take account of the fact that the quality of the social determinants of health to which citizens in a jurisdiction are exposed to is shaped by public policy created by governments. And governments of course are controlled by political parties who come to power with a set of ideological beliefs concerning the nature of society and the role of governments.

Such analyses that recognize the role played by politics outline the particular importance of having social democratic political parties in power. Nations that have had longer periods of social democratic influence such as Norway, Finland, Sweden, and Denmark have government policymaking that is remarkably consistent with social determiannts of health concepts. Nations such as the USA and Canada,dominated by liberal and neo-liberal governing parties, much less so. The work of David Coburn, Toba Bryant, Clare Bambra, Richard Hofrichter, Carles Muntaner, and Vicente Navarro has been especially attentive to these issues.

A wealth of evidence from Canada and other countries supports the notion that the socioeconomic circumstances of individuals and groups are equally or more important to health status than medical care and personal health behaviours, such as smoking and eating patterns (Evans et al., 1994; Frank, 1995; Federal/Provincial/Territorial Advisory Committee on Population Health, 1999).

An example of SDOH, applicable to the United States, is shown in the graph, below. It shows self-reported health as it relates to income level and political party identification (Democrat vs. Republican).

The weight of the evidence suggests that the SDOH have a direct impact on the health of individuals and populations, are the best predictors of individual and population health, structure lifestyle choices, and interact with each other to produce health (Raphael, 2003). In terms of the health of populations, it is well known that disparities-the size of the gap or inequality in social and economic status between groups within a given population-greatly affect the health status of the whole. The larger the gap, the lower the health status of the overall population (Wilkinson, 1996; Wilkinson and Marmot, 1998).