Be equal, be healthy

Unhealthy Societies is much more than another book on inequalities in health - it provides an elegantly argued treatise on the problems facing contemporary societies. Richard Wilkinson, an economist by training, has written an insightful sociological book which builds on both disciplines, while providing a cogent critique of many conventional economic ideas. It is a methodologically sophisticated, yet inherently readable book.

Wilkinson's book explores an apparent paradox between divergent findings for individuals and between societies. At the individual level, there is clear evidence that poor health and the chances of premature mortality are higher for individuals with lower incomes. People at the top of the income distribution have two to three-fold lower mortality rates than those at the bottom. However, in developed societies there is little relationship between the wealth of a society, measured by the GNP per capita, and the average expectation of life in that society. People living in countries with a high GNP, such as the United States and West Germany, on average die three to four years younger than in countries with a lower GNP, such as Sweden, the Netherlands and Japan. Wilkinson cogently demonstrates that what distinguishes countries with the highest expectation of life is not the absolute wealth of the country but the narrowness of income inequalities in these countries.

Fascinating evidence from a range of countries is used to demonstrate the persistence of the finding that relative income inequalities within a society have a major impact on the overall level of health of that society. For example, Japan in 1970 had an expectation of life comparable to the United Kingdom, but during the following two decades experienced a remarkable reduction in income inequality, now recording the lowest income inequality of any country in the Organisation for Economic Cooperation and Development, while also achieving the highest expectation of life in the world.

The greatest reductions in mortality in Britain occurred in each of the decades around the two world wars, when there were gains of six years in the expectation of life, compared with gains of no more than two years in any other decade this century. During the wars, there was full employment and a reduction in income inequality, as well as improved nutrition because of rationing in the second world war. Health inequalities in Britain reached their lowest level in 1951, and since then have increased in each decade. Britain saw an unprecedented increase in income inequality during the late 1980s, and at the same time Wilkinson presents dramatic findings of increased inequalities in health, including an increase in mortality among working-age men living in more deprived areas.

Wilkinson shows how relative poverty has replaced absolute poverty as the key process underlying inequalities in health. He argues that egalitarian societies are more socially cohesive, and that social cohesion is the primary factor associated with quality of life and good health. More egalitarian societies have a stronger community life, fewer signs of antisocial behaviour and lower crime rates. These factors affect the health and well-being of everyone in the society.

Medicine has dominated our understanding of health, with the assumption that the health of a society is directly related to expenditure on the health care system, and technological developments in medicine. However, Wilkinson shows that medicine has very little influence on the health of a country's citizens. The US has the highest per capita health expenditure in the world, nearly 15 per cent of GNP, but even the well-off in the US have a poorer expectation of life than the average person in Sweden, while blacks in Harlem die younger than people living in rural Bangladesh.

Similarly there is a pervasive ideology that we can all preserve our health by not indulging in behaviour which is considered a health risk factor, whether it is smoking, taking too little exercise or eating too many chips. But research shows these have little effect on health compared with social structural factors. Health is a social product and the challenge is now to understand how a person's position in the social hierarchy affects his or her health.

For Wilkinson, the key is to understand the psychosocial pathways linking status inequalities to health. The effects of economic factors are transmitted largely through chronic stress, related to lack of control over one's situation, particularly associated with job, housing and income insecurity, lack of social supportive networks, depression and low self-esteem. There is ample evidence of the effects of unemployment and fear of redundancy on ill health. Wilkinson delves into physiology showing how chronic stress influences the immune system.

The moral message is that we neglect at our peril the enormous burden of growing rates of deprivation among families, which result in increased levels of chronic stress for both the parents and their children. Within a competitive and individualistic society with substantial income inequality, the material environment provides a constant reminder of an individual's failure according to the key status criteria of that society. Quality of life is ultimately a matter of people's sense of well-being.

Wilkinson demonstrates the missing social economy of well-being, which tends to be neglected by economists who concentrate on maximising individual consumption. We need to understand the way in which wider social structures have been associated with narrower income differences and better health. It is important to see income differentials as enmeshed within wider patterns of ideology and social and economic relations.

The political message of this book is clear, that income distribution is narrowed only when governments believe they cannot afford not to narrow it, and that the health of all members of a society benefits from the degree of egalitarianism and social cohesion within a society. This scholarly and insightful book is recommended reading for all students of sociology and economics, as well as health policy-makers and politicians.

Sara Arber is professor of sociology, University of Surrey.