Commentary: Liberty, fraternity, equality

Abstract

The relationship between income inequality and health has been independently discovered several times by people who appeared not to know of each other's work.1,2 When I first published on the subject3 I too was unaware of Rodgers' paper4 until George Davey Smith pointed it out to me. Rodgers introduced an income distribution term into his regressions simply to take account of the well-known curvature of the international relation between gross national product (GNP) per capita and life expectancy as countries go through the so-called epidemiological transition. In contrast, I came to the subject through an interest in health inequalities within Britain. While using occupational incomes and death rates to discover whether death rates were responsive to changes in incomes for which people were not self-selected,3,5 I also wanted to know whether the shape of the individual relation between income and mortality within Britain was linear or curvilinear. My interest in this point was explicitly to find out whether, if income was redistributed from the rich to the poor, the health of the poor would benefit by more than the health of the rich would suffer: I wanted to know if average health would be improved by redistribution. Having been convinced by my results both that mortality was responsive to changes in income and that the health of the poor was more sensitive to changes in income than that of the rich, I thought it might be worth looking to see whether national mortality rates were lower in countries with a narrower income distribution. Mildred Blaxter had mentioned to me that she thought there was such as relationship though she had not looked at it herself. My first three papers on income distribution3,5,6 were all accompanied by evidence that the individual relation between income and health or mortality was curved: that not only seemed to lend plausibility to a causal interpretation of the cross-sectional relationships between income distribution and mortality in different countries, it was why I thought they existed. It was then a little annoying when, a few years later Gravelle7 suggested, as if it were a new hypothesis, that the income distribution relationship might be explained by the curvature of the individual relation between income and health. He did so without reference to the evidence in my earlier papers, although I had pointed it out to him when he sent me a draft of his paper for comment. It was George Davey Smith who originally suggested to me that income distribution might be associated with health for reasons unconnected with the curvature of the individual income health relation (ref. 8, p. 105). I had previously done some back-of-an-envelope calculations of how large a part of the health disadvantage associated with low socioeconomic status it would be necessary to remove to produce the improvement in average health that seemed to be associated with greater equality. The evidence then available suggested it was a substantial proportion and could not be accounted for by improvements to the poorest alone. At around this time I became increasingly interested in the fact that the curvature of the international relationship between income distribution and life expectancy was not the same as the social gradient in health within the developed countries. Indeed if you looked at the position of the US on graphs showing the relation between GNP per capita and life expectancy internationally, it was clear that even Americans on half the average US income (a commonly used definition of poverty) were still on the relatively flat part of the international curve. So it seemed as if the health inequalities were about something purely internal to a society. Michael Marmot had been exploring psychosocial explanations of the social gradient for some time and indeed had set up Whitehall II to advance that process. Later Clyde Hertzman made us aware of the animal models of the relationship between health and social status.9–11 The great advantage of the monkey studies was not only that social status could be experimentally manipulated among captive animals, so increasing our confidence in the direction of causality in the health and social status relation but, for the first time, it was possible to make an unambiguous separation of material living standards and social status. Although among humans higher social status almost always goes with better material conditions (indeed the connection between social dominance among animals and social stratification in humans is that both are about gaining privileged access to resources) among captive monkeys it was possible to ensure that they all had the same diets and lived in the same compounds.11 While these studies demonstrated that low social status could have implications for health among monkeys even when material conditions were held constant, the biological effects of chronic exposure to stress were also becoming clearer and better known. Because their health consequences seemed so widespread, involving the endocrine, cardiovascular and immune systems—and more, psychosocial risk factors began to look like the generalized vulnerability factor capable of explaining why so many different diseases were more common lower down the social scale which had been proposed by Michael Marmot12 and seconded by Sally MacIntyre.13 The physiological processes consequent on chronic stress also seemed to meet other theoretical demands: they were compatible with a period of special sensitivity in early life, with cumulative effects throughout life, and with an impact of current circumstances—just what the epidemiology of health inequalities needed. The impression that population health was more closely related to income distribution than to average income (which initially seemed true of developed countries and still seems true of US states and cities) added to the reasons for thinking that the social gradient in health was, as the animal studies had suggested, principally about social status rather than levels of material consumption. But we needed some new thinking to understand why. We needed to theorize social status as a psychosocial risk factor, and the biology tells us that this means theorizing it as a source of chronic stress. Some years earlier the most obvious way of doing that would simply have been to list all the ways in which low social status was associated with sources of anxiety like debt, job and housing insecurity, and the many other difficulties of life on a low income. But two factors seemed to be pointing to something rather more fundamental. The first was that the health and income distribution relationship had led to a recognition, new at least to epidemiologists, that places with bigger income differences seemed to be less socially cohesive. While writing my book Unhealthy Societies8 I had surprised myself when I decided that before discussing the individual psychosocial risk factors which might explain why more egalitarian societies tended to be healthier, I would have a chapter looking at whether there were broader sociological characteristics which distinguished healthier more egalitarian societies from others. Surprised, because the impressionistic qualitative evidence was much stronger than I had expected. Admittedly, the examples I took—Britain in the two world wars, Roseto14 and Japan—were highly selected. Soon the hypothesis that the quality of social relations was better in more egalitarian societies was supported by data from a number of other sources. Ichiro Kawachi and Bruce Kennedy15 used a measure of trust as an indicator of the quality of social relations and found that ‘social trust’ seemed to mediate between income inequality and mortality in the 50 states of the US. Finding that there was a substantial literature showing that homicide rates were higher in more unequal societies came as another impressive confirmation of this picture—‘a novel post-diction’ as philosophers of science used to say. There are over 40 papers on the subject and the relationship seems robust, both within and between countries.16 We found that among the 50 states homicide rates (used as an indicator of the quality of social relations) also mediated statistically between inequality and death rates from all non-violent causes of death17—i.e. the states with social environments which produced high homicide rates also produced high death rates from other causes. Homicide seemed to be related to inequality because it was so frequently triggered by disrespect—being ‘dissed’—particularly when sensitivities were increased by relative deprivation.18,19 Bruce Kennedy20 also showed that racial prejudice was associated with greater inequality. Finally, Robert Putnam emphasized the strong links between his measures of ‘social capital’ and an egalitarian social ethos—cross-sectionally in his Italian study, and both cross-sectionally and over time in his study of involvement in community life in the US (ref. 21, pp. 102–05 and note 52 p. 224; ref. 22, p. 359). On their own these links seemed more of a clue to, than an explanation of, the inequality relationship: going to meetings of community groups, not getting murdered, and trusting others, are not in themselves normally regarded as sufficient conditions to ensure good health. The second pointer comes from the main psychosocial risk factors for population health. In terms of population attributable risks, the three most powerful of these must be low social status itself, all the various measures of social affiliation, networks, support, etc, and stress in early life (probably pre-natal as well as in early childhood).9,23–26 Having control over one's work27 may function partly as the fine grain of social status, in that if you do not have control of your work it usually means you are subordinate to someone else: a close synonym for having control in this context might be autonomy and its opposite would be subordination. If we think of these intensely social risk factors as telling us about the most powerful sources of chronic stress in our society, then we can see that they may be different clues to the same inner source.26 The personal insecurities which come from early childhood are not unlike the insecurities and fears of inadequacy which come from low social status. Both are associated with higher basal cortisol levels, and early childhood insecurities must make us more vulnerable to the insecurities of low social status. Friendship fits easily into this picture: friends provide positive feedback and reassurance of one's acceptability and attractiveness, whereas not having friends, or feeling rejected, does the opposite and fills us with self-doubt. We worry about being unattractive, fat, boring, stupid, or gauche, and fear negative social comparisons. As reflexive beings we know ourselves —and actually experience ourselves—partly through each other's eyes. We monitor how others react to us. How we imagine they see us can fill anyone with overwhelming embarrassment, pride, shame, or whatever. These social anxieties are almost inescapably part of negotiating our way through social space, indeed they guide our behaviour and we cannot avoid monitoring how others respond to us. But some social environments make these processes more anxiety laden than others. While being among friends is clearly reassuring, finding ourselves in a society where people appear to be ranked according to ability and attractiveness, from the most able and successful at the top, to the most unattractive failures at the bottom, inevitably generates anxiety about ranking. Where some people appear to count for everything and others for nothing, and processes of class prejudice and discrimination mean that we take people's status as a reflection of their abilities, few can avoid worrying about where they come. We can now start to see how this inner angst about how we negotiate social space is affected by hierarchy, by friendship and, through its impact on our emotional resilience, by early childhood experience. In this context, one of the most interesting graphs Robert Putnam provides in his Bowling Alone22 shows that in the more unequal parts of the US, where participation in community life is lower, it is particularly the poorer people who have ceased to participate (Fig. 93 p. 361, note 16 p. 497). Where there is more income inequality, poorer people are more likely to feel out of place participating in community groups, more likely to feel ill at ease and to think that they will make fools of themselves and be looked down on. We know that there is more racial prejudice in those areas20 and it would be surprising if there was not also more class prejudice and stigma. We now have the theoretical basis on which to integrate the personal psychological world into the broader social structure.28 It is a perspective which allows us to understand not just the impact of social structure in the broadest societal terms, but presumably also the effect of how institutions work, of how junior staff are treated, whether they feel valued or used, whether institutions are more egalitarian and inclusive, or more divisive and authoritarian. We can take another important step in understanding what is going on if we ask why hierarchy and the quality of social relations have a double link between them: first, as they are powerful health risks factors (low social status and weaker social affiliations are both strongly associated with worse health) and second, as they vary inversely in societies (more inequality being associated with less trust, more violence and less community participation). On the face of it these two links seem quite independent of each other. But the reason why they move inversely in societies and are both related to health is surely because they are the opposite sides of the same coin. Social stratification, dominance hierarchies or ‘pecking orders' are (among humans as among animals) principally about privileged access to resources based on coercion and superior power, regardless of the needs of others: that is why the ‘high’ are also the ‘mighty’ and get the lion's share. Friendship on the other hand is exactly the opposite of that. It is about sharing, mutuality, reciprocity, social obligations, and a recognition of each others needs. The gift is a mark of friendship because, between giver and receiver, it symbolizes a renunciation of conflict for access to scarce resources. We are dealing then with the fundamental elements of human social relationships: with whether we are threats to each other, or sources of help and support. Human beings can associate either on the basis of strength and superior power or on the basis of co-operation. Which we do has important implications for whether other people are a source of anxiety and stress, or whether they provide a sense of security and relaxation. Relations of one kind are damaging to health, and of the other, are beneficial. But how relationships are structured is not of course simply a matter for individual decisions: we find ourselves in a particular society with a set of institutions which already structure relationships into patterns of dominance and subordination, superiority and inferiority within which we have definite class positions. Social status, friendship and equality impact so strongly on the quality of our lives that they have long been recognized as important political issues. Indeed, they translate directly into the revolutionary demand for liberty, fraternity, and equality—the slogan still reproduced on some of the French versions of the Euro coins. At the time of the French revolution, liberty meant not being subjected to the arbitrary power of the aristocracy and feudal nobility, not being subordinate or beholden to anyone. It expressed the desire to avoid the invidiousness of low social status, loss of autonomy, and subordination. Fraternity, or at least some less sexist term such as friendship, comradeship or is just the human for and social relations that we know are associated with better health. Finally, equality is a for the other for liberty because only in the more egalitarian and less societies can the of social inferiority and be and for friendship, because we to our friends among our and find it to negotiate the social by differences in and we have a of health that is a of human social our psychological needs as human beings to the social structure in which we But it is a that also has important implications for the position of only are more unequal societies more they are also more unequal societies seem not only to have more class and racial but also more discrimination Indeed, the position of is to until social relations in the space more status to be better in societies where income differences among are The well-known for health to be better in societies where status is better may be a reflection of the fact that status is likely to as an indicator of the of the social more It is not just health, or even and health, which is better in such but health as that among animals access to was one of the most important resources which to and that in dominance hierarchies to the higher status dominance relationships are likely to have implications for relations between the and have found as on of status more important and other for less important in more unequal In such a context we not be surprised by the violence that comes when feel they are being and just when the theoretical seems to be its look as if they are to of the is that some are the effects of income distribution as only the effects for individual income. has those who that individual income material effects of income from more effects of psychosocial But that one of the most of the social gradient in health is that it partly the impact of individual social position social on health, this is Social social status, relative are or social than being individual they are about position in a social In terms, it is also to as inequality effects are mediated by people's individual within the social context, inequality does not if narrower income distribution is related to health, it little to which it for what it is worth and results from other the study which much the most data that more than half of the income distribution relationship even for the relation between individual income and But that is not the only Although income distribution has now been to be related to mortality or in many different there is now more than a of that do not such a But over the years relationships have been in the US among all and among in and among and in within among the of the among the of and in as well as times in international studies using different data and to explain the relationship are to more than one of the many in which it developed countries the international relation between income distribution and mortality now to be to a few and does not among the who account for the of In although mortality rates are much as we might income there is evidence of a relation within studies using US data have found that in as as or relations are or of the is that if you the two inequality within an and the income of the you then move to or of some of the differences in the income inequality of will get to differences in income between the means that which would be income inequality in income in and is as if it only affected health as income. can either is why between income inequality and health to be in and in exactly the opposite is true of between income and If we take as the of we are of course to individual income. At that all the income that would be income distribution in as individual many would that it is actually individual income relative to others. So where go from might we take of negative can be to relationships to health time, before other factors have been into It seems likely that the in the distribution of relative from the

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