Improving population health means more than reducing inequality

Growing concern over rising inequality has renewed interest in the effects of inequality on health. But the science is not as straightforward as many think.

There was a time, about 20 years ago, when research into inequality and health seemed to tell a simple, coherent and compelling story. The research showed that there were social gradients in health, such that at any point in the social hierarchy, people on average had worse health than those above them and better health than those below them. More unequal societies had more unequal health--i.e., steeper gradients in health. And more unequal societies appeared to have poorer average health--that is, inequality was bad for everyone's health, not just those of lower socio-economic status.

However, as public and political interest in inequality and health has increased, the scientific story appears to have become less clear. It remains true that poverty and disadvantage harm health, and that most societies have social gradients in health. But more unequal societies do not necessarily have more unequal health, raising doubts about whether reducing inequality would reduce health inequalities. And whether more unequal societies have worse health overall remains contested and inconclusive, despite hundreds of studies over several decades. Empirical findings are inconsistent and contradictory and there is still no consensus among researchers.

Even by the early 2000s, some reviews were challenging the view that income inequality was a major determinant of differences in population health. The debate continues to this day. A 2009 study found only a 'modest' effect of income inequality on health, and called for further investigations. A 2014 study of 28 European countries showed that there were simple correlations between income inequality and a range of measures of health and wellbeing. However, unequal societies were on average much poorer; once per capita GDP was taken into account, national inequality did not reduce health or wellbeing. 'These results all imply that directing policies and resources towards inequality reduction is unlikely to benefit the general public in advanced societies', the authors say.

In the public debate, the 2009 best-selling book, The spirit level: why equality is better for everyone, by British epidemiologists Richard Wilkinson and Kate Pickett has attracted most attention. Reflecting the emphasis on inequality in the research on social determinants in general, Wilkinson and Pickett attach great importance to tackling inequality in shaping social outcomes, including improving the health and quality of life of all of us.

More than this, reducing inequality would help us to address other problems: we can regain a sense of optimism that social and environmental problems can be solved, they write, knowing that 'greater equality will help us rein in consumerism and ease the introduction of policies to tackle global warming'. Their vision has seen health inequalities become part of broader debates about progress and sustainability.

At the core of Wilkinson and Pickett's argument is the effect of inequality on social relations, which in turn affect health: 'greater equality is the material foundation on which better social relations are built', they write. In explaining how inequality gets 'under the skin', they stress the importance of social judgements and evaluations to wellbeing, and of inequality as a cause of 'social evaluation anxieties'.

At the most fundamental level, they write, reducing inequality is about 'shifting the balance from the divisive, self-interested consumerism driven by status competition, towards a more socially integrated and affiliative society'. 'Greater equality can help us develop the public ethos and commitment to working together which we need if we are going to solve the problems which threaten us all.'

However, it is conceptually and empirically flawed to attribute qualities like self-interest and consumerism so narrowly to inequality. It is not obvious, for example, that income inequality would have more impact on social relations, including social comparisons and status competition, than the way modern Western culture construes the self and its relations to others through qualities such as individualism and materialism.

If perceptions of social status influence levels of stress and anxiety, then cultural factors also play a critical role: for example, amplifying a sense of relative deprivation through media images of 'the good life' and celebrity lifestyles that are increasingly beyond the reach of most people; or moderating it by providing alternative cultural models, such as downshifting and simple living, that undermine conventional social comparisons. Culture also influences the social distribution of risky behaviour like smoking and alcohol use, modifying income-related health gradients and helping to explain why more unequal countries do not always have more unequal health.

More importantly, culture has a wider significance as a system of meanings and symbols that defines how people see the world and their place in it, and gives meaning to personal and collective experience. Every aspect of reality is embedded within webs of meaning that define a certain worldview and that vary with individuals, times and societies. In other words, cultures define what we know about the world, and so what we do; in this sense they are fundamental to population health and wellbeing.

Research shows, for example, that materialism--giving priority to money and what it buys--has increased among young Americans over several generations, a rise attributed to cultural reinforcement and social instability and disconnection). Materialism was already rising rapidly in the 1970s (the earliest data used in the study) and peaked in about 1990, so the trend does not track that of inequality. Materialistic values are associated with: lower life satisfaction, happiness and vitality, and higher depression and anxiety; less prosocial and cooperative behaviours, and more antisocial and competitive behaviours; and more environmentally damaging and unsustainable choices and lifestyles.

Reflecting increasing individualism as well as materialism, other studies have found that extrinsic goals (money, image, fame) have become more important since the 1960s among American high school and college students, and intrinsic goals (self-acceptance, affiliation, community) less important; concern for others, civic orientation and environmental action have declined. Such trends have obvious implications for the quality of social relations, and so health and wellbeing. Other US studies have taken adverse trends in young people's psychological health back as early as the 1930s, so spanning a sustained period of declining inequality.

In arguing for a new narrative of declining health and wellbeing among young people in developed countries, I have suggested that the central dimension of the changed trajectory in their health over recent decades is a shift in relative importance from structural determinants to cultural; from socio-economic deprivation to psychosocial deprivation. The costs include a loss of social integration, intrinsic worth, moral clarity and existential confidence. One result is that mental health problems have become more significant, accounting for by far the biggest share of the burden of disease in at least some Western countries. Most mental illness begins in childhood, adolescence and early adulthood and affects people in the most productive years of life, increasing the personal, social and economic costs. In contrast, the burden of chronic physical diseases such as cancer, stroke and heart disease falls predominantly on the elderly.

One reason that research into health inequalities, both within and between countries, has attracted so much attention and support is that it resonates with a progressive ideology, which emphasises social justice and equity, at a time when neoliberalism or market fundamentalism has become more powerful, and inequality is rising in many countries.

This appeal is understandable: the research fits within the current political paradigm, with its contest between the progressive left and the conservative right. Inequality is also relatively easily addressed through changes in public policy in areas such as taxation, housing, education and health. On the other hand, recognising the complex dynamics of social influences on health suggests far deeper, systemic changes in society are required.

In raising my doubts about the role of inequality in health with epidemiological colleagues, one cautioned against a 'narcissism of small differences' (where differences are exaggerated to enhance or distinguish one's own position). The key is to bring together people who want to move society forward rather than emphasising differences, even when these are not that small, he said.

However, science must strive to rise above ideology, and this is especially important in politically laden issues like inequality. Furthermore, there are costs in overstating the importance of inequality (as distinct from poverty and disadvantage) to health. First, given the legitimate doubts and uncertainties about the research, it risks weakening the arguments for equality. More importantly, in the wider context of humanity's problematic future, the case for fundamental change becomes much stronger when we look, not just at inequality, but at all the structural and cultural foundations of modern life, and the multiplicity of their interactions.

Reducing inequality may well be a good thing for many reasons, including improving health, but it will not solve the persistent and sometimes worsening problems of population health and wellbeing.