Turrell and Mathers (2000) outline a model of upstream (closer to the source of the problem), midstream and downstream factors that determine whether people like Chris will develop heart disease. These risk factors are synergistic; that is, the combinations of factors interact to produce a compounding effect rather than being additive (Higginbotham et al 2001, p 94). Throughout this chapter, you should come to realise how interrelated all of these factors are, and that Chris’ health problems are likely to have resulted from a combination of factors from all three levels of this model rather than one specific element.

Upstream, or macrosocial factors, include economic, political, and tax policies as well as employment status, education, income, and area of residence. For example, upstream factors influencing the development of Chris’ health problems might also include the poverty he experienced in early childhood, especially after his father died. Worldwide, poverty is a serious threat to the health of several billion people (Horton 2003, p 713), so it is worthwhile discussing in some detail here.

Poverty is defined as ‘as a state of deprivation, a situation where one’s standard of living has fallen below some acceptable minimal level’ (Harding, Lloyd & Greenwell 2002, p 2). Social scientists who research poverty have focused on relative poverty where the after-tax income of a family is lower in comparison to the average income for that size family in a specific nation at that time. Up to 17.5% of Australians live in financial hardship and, not surprisingly, more than half of unemployed people live in poverty (Harding et al 2002). Their vulnerability is also increasing, reflecting the slower increase in unemployment benefits during the late 1990s in comparison to average wages (Harding et al 2002).

Traditionally, women constituted the biggest group of poor people. Australia’s first and only formal inquiry into poverty in the early 1970s found that women and children were over-represented amongst the poor (George & Davis 1998). People living in sole parent families continue to face the highest risk of poverty of all family types. Twenty-two per cent of sole parent families lived in poverty in Australia in 2000 (Harding et al 2002). Given that his father died prematurely, Chris was living as a child and teenager in a femaleheaded sole parent family during the 1960s. For many decades, and until very recently, there was very little medical research into CHD in women. One terrible consequence of this is that, at present, women living in poverty are 124 times more likely to die from CHD than wealthier women (Higginbotham et al 2001). Women’s symptoms can differ from men’s, they receive less thorough investigations, are likely to be diagnosed later, be treated less aggressively in cardiac emergencies, have less family support during rehabilitation, and return to work sooner (Gorman 2003).

Children remain the age group most vulnerable to poverty, rising to 15% of Australian children in 2000 (Harding et al 2002). This is disconcerting, given that poorer adult health is greatest among those who had childhood disadvantage similar to that experienced by Chris. Children from poorer families are more likely to be underweight at birth; become developmentally delayed; experience higher rates of pedestrian accidents; and have long-term health problems (Turrell & Mathers 2000). Thus, disease risk accumulates over a lifetime and the worst health accrues to those with the highest levels of economic and social adversity.

The economic and social adversity that Chris experienced as a child can be the result of inequalities between social groups, which are often explained in terms of class. Social class is one of those in-built differences between groups of people in a given society that is commonly unnoticed, or accepted as ‘the way things are’ and therefore not questioned. Such fundamental inequalities relate to what cannot be chosen. For example, in general neither we, nor our parents, can choose the income level of our parents, our gender, race, or class. These are circumstances into which we are born.

Class is defined as a ‘position within a system of structured inequality based on the unequal distribution of power, wealth [and] income … ’ (Germov 2002, p 68). In a western capitalist country like Australia, class refers to groups of people on the basis of economic ownership and political power. The upper class owns economic resources, such as raw materials, technology and businesses. It includes senior executives and managers who have indisputable control over workers and access to profits through very high incomes and significant share holdings. Power and wealth remain concentrated within the upper class (Giddens 2001). The working class is made up of unskilled or semiskilled workers who work in factories, offices and other settings. The middle class is differentiated from the working class by a combination of higher skill level, better working conditions and less vulnerability to market forces (predictable or unpredictable) that create unemployment and limited retraining opportunities. According to this three-stage explanation of class, 9% of Australians belong to the upper class; 47% to the middle class; and 44% to the working class (Germov 2002).

The term socioeconomic status (SES) is based on a less critical view of structured inequalities in comparison to the class model. SES is defined as the hierarchical ranking of people according to income, occupation, level of education and area of residence, and then grouping them into high, medium, and low SES groups.

Midstream or microsocial determinants of health include psychosocial factors like the individual’s control of stress, life circumstances, demand strain at work and home, social support, self-esteem and coping skills. Health behaviours such as diet, cigarette smoking, alcohol and physical activity are also midstream factors. Chris has several of the known midstream risk factors for developing heart disease, including cigarette smoking and high body mass index. Midstream factors, such as ignoring healthy lifestyle information, clearly played their part in increasing his risk of developing CHD over many decades.

Studies have shown that people like Chris, who had little control over his work, are at greater risk for heart disease, musculoskeletal problems and mental disorders such as depression (Marmot 2000). In fact, some research shows that job strain more than doubles the death rate from CHD (Kivimaki et al 2002). Job strain relates to a combination of work demands, such as high levels of responsibility, task difficulty and mental load; along with low job control as evidenced by lack of decision making autonomy and skill discretion. These two work-related factors—effort reward imbalance and job strain—are clearly related to class. Working class people employed as unskilled or semi-skilled labour will experience effort–reward imbalance in high demand jobs, involving work pace, high levels of supervision, and long hours (Higginbotham et al 2001). Skilled working class and middle class employees like Chris will experience job strain in positions with high responsibility and low levels of policy and managerial power and autonomy, even though their education or training prepare them for expert autonomous decision-making. So although he came from a lower class family, Chris now considers himself to be middle class—and he certainly is not poor or uneducated. However, he has not been in control of his work circumstances and has experienced considerable pressure to produce results from both employers and clients—which has contributed directly to his chronic illness.

Downstream determinants of health are non-modifiable and include gender, age, genetic inheritance; as well as endocrine or immunological outcomes such as hypertension, fibrin production, excessive blood lipid levels, glucose intolerance and high body mass index (Turrell 2002, Turrell & Mathers 2000). Chris’s family history indicates that he may have a predisposition to these factors, as do his high blood pressure and raised cholesterol levels. Chris’s gender is also included in the non-modifiable risk category—before the age of 50, men are more likely to develop CHD than women.

Clearly, mid- and upstream factors have played a part in Chris’ disease process and have exacerbated the risks related to the downstream factors he has little control over. For example, a downstream factor such as blood pressure increases in response to midstream factors such as obesity, high alcohol consumption, and the over-use of salt. Smoking more than doubles the incidence of CHD (Higginbotham et al 2001). Similarly, raised cholesterol is a by-product of a diet high in saturated fat, excessive alcohol intake and cigarette smoking, as well as insufficient exercise and being overweight. It could be that factors such as the class and income of his family of origin laid the foundations for midstream negative health-related behaviours. Another midstream factor is proposed by Heading (1996) who has identified one group of people as health promotion ‘resisters’ (cited in Higginbotham et al 2001). Resisters are mostly men who know the facts about lifestyle and heart attack risk, but who choose not to initiate positive changes in eating, smoking or exercise. Chris could be described as a ‘resister’. Downstream factors of heredity and ageing come into play against this general background of an unhealthy lifestyle and resistance to a healthy one.

Turrell and Mather’s (2000) model is a useful way to demonstrate that the biological factors that contribute to the risk of disease can occur because of a range of psychosocial factors, including a person’s health-related behaviours. These factors are, in turn, influenced by economic, environmental and social stressors, having a cumulative effect upon a person’s health. It has been recognised for some time that justice and equity of access to health services should be a key principle in public health that may address mid- and upstream factors (Drevdahl et al 2001, p 22). It is also well known, however, that injustices and inequity of access to health services contribute to poorer health outcomes for poorer people. These class-based factors must be taken into account by policy makers, including nurses, so that health policy and programs identify effective strategies to prevent CHD and other long-term illnesses in all sectors of our society. One way of determining equitable distribution of health resources is to use standard measures of health and illness inequalities. These are discussed in the following section.