Those in lower grades were indeed more likely to be obese, to smoke, to have higher blood pressure and to be less physically active, but these risk factors explained only one-third of their increased risk of deaths from heart disease.67 And of course factors such as absolute poverty and unemployment cannot explain the findings, because everybody in these studies was in paid employment. Of all the factors that the Whitehall researchers have studied over the years, job stress and people’s sense of control over their work seem to make the most difference. There are now numerous studies that show the same thing, in different societies and for most kinds of ill-health – low social status has a clear impact on physical health, and not just for people at the very bottom of the social hierarchy. As well as highlighting the importance of social status, this is the other important message from the Whitehall studies. There is a social gradient in health running right across society, and where we are placed in relation to other people matters; those above us have better health, those below us have worse health, from the very bottom to the very top.68 Understanding these health gradients means understanding why senior administrators live longer than those in professional and executive grades, as well as understanding the worse health profiles of the poor.
Besides our sense of control over our lives, other factors which make a difference to our physical health include our happiness, whether we’re optimistic or pessimistic, and whether we feel hostile or aggressive towards other people. Our psychological wellbeing has a direct impact on our health, and we’re less likely to feel in control, happy, optimistic, etc. if our social status is low.
It’s not just our social status and psychological wellbeing that affects our health. The relationships we have with other people matter too. This idea goes back as far as the work on suicide by Émile Durkheim, one of the founding fathers of sociology, in the late nineteenth century.69 Durkheim showed that the suicide rates of different countries and populations were related to how well people were integrated into society and whether or not societies were undergoing rapid change and turmoil. But it wasn’t until the 1970s that epidemiologists began to investigate systematically how people’s social networks relate to health, showing that people with fewer friends were at higher risk of death. Having friends, being married, belonging to a religious group or other association and having people who will provide support, are all protective of health.70–71
Social support and social networks have also been linked both to the incidence of cardiovascular disease and to recovery from heart attacks. In a striking experiment, researchers have also shown that people with friends are less likely to catch a cold when given the same measured exposure to the cold virus – in fact the more friends they had, the more resistant they were.72 Experiments have also shown that physical wounds heal faster if people have good relationships with their intimate partners.73
Social status and social integration are now well established as important determinants of population health and, increasingly, researchers are also recognizing that stress in early life, in the womb as well as in infancy and early childhood, has an important influence on people’s health throughout their lives.74–75 Stress in early life affects physical growth, emotional, social and cognitive development, as well as later health and health behaviours. And the socioeconomic status of the families in which children live also determines their lifelong trajectories of health and development.76
Taken together, social status, social networks and stress in early childhood are what researchers label ‘psychosocial factors’, and these are of increasing importance in the rich, developed countries where material living standards, as we described in Chapter 1, are now high enough to have ceased to be important direct determinants of population health.
LIFE IS SHORT WHERE LIFE IS BRUTAL
Evolutionary psychologists Margo Wilson and Martin Daly were interested in whether adopting more impulsive and risky strategies was an evolved response to more stressful circumstances in which life is likely to be shorter. In more threatening circumstances, then, more reckless strategies are perhaps necessary to gain status, maximize sexual opportunities, and enjoy at least some short-term gratifications. Perhaps only in more relaxed conditions, in which a longer life is assured, can people afford to plan for a long-term future.77 To test this hypothesis, they collected data on the murder rates for the seventy-seven community areas of Chicago, and then they collected data on death rates for those same areas, subtracting all of the deaths caused by homicide. When they put the two together, they showed a remarkably close relationship, seen in Figure 6.1 – neighbourhoods with high homicide rates were also neighbourhoods where people were dying younger from other causes as well. Something about these neighbourhoods seemed to be affecting both health and violence.
In Chapter 4 we showed how different developed countries and
Figure 6.1 Homicide rates are related to male life expectancy in seventy-seven neighbourhoods in Chicago. (Calculation of life expectancy included deaths from all causes except homicide.)77
US states vary in the levels of social trust that people feel. There are sixfold differences in levels of trust between developed countries and fourfold differences among US states. We mentioned that levels of trust have been linked to population health and, in fact, research on social cohesion and social capital has mushroomed over the past ten years or so. More than forty papers on the links between health and social capital have now been published.78
In the United States, epidemiologist Ichiro Kawachi and his colleagues at the Harvard School of Public Health looked at death rates in thirty-nine states in which the General Social Surveys had been conducted in the late 1980s.79 These surveys allowed them to count how many people in each state were members of voluntary organizations, such as church groups and unions. This measure of group membership turned out to be a strong predictor of deaths from all causes combined, as well as deaths from coronary heart disease, cancers, and infant deaths. The higher the group membership, the lower the death rate.
Robert Putnam looked at social capital in relation to an index of health and health care for the US states.25 This index included information on such things as the percentage of babies born with low birthweight, the percentage of mothers receiving antenatal care, many different death rates, expenditure on health care, the number of people with AIDS and cancer, immunization rates, use of car safety belts, and numbers of hospital beds, among other factors. The health index was closely linked to social capital; states such as Minnesota and Vermont had high levels of social capital and scored high on the health index, states such as Louisiana and Nevada scored badly on both. Clearly, it’s not just our individual social status that matters for health, the social connections between us matter too.
HEALTH AND WEALTH
Let’s consider the health of two babies born into two different societies.
Baby A is born in one of the richest countries in the world, the USA, home to more than half of the world’s billionaires. It is a country that spends somewhere between 40–50 per cent of the world’s total spending on health care, although it contains less than 5 per cent of the world’s population. Spending on drug treatments and high-tech scanning equipment is particularly high. Doctors in this country earn almost twice as much as doctors elsewhere and medical care is often described as the best in the world.
Baby B is born in one of the poorer of the western democracies, Greece, where average income is not much more than half that of the USA. Whereas America spends about $6,000 per person per year on health care, Greece spends less than $3,000. This is in real terms, after taking into account the different costs of medical care. And Greece has six times fewer high-tech scanners per person than the USA.
Surely Baby B’s chances of a long and healthy life are worse than Baby A’s?
In fact, Baby A, born in the USA, has a life expectancy of 1.2 years less than Baby B, born in Greece. And Baby A has a 40 per cent higher risk of dying in the first year after birth than Baby B. Amon
g developed countries, there are even bigger contrasts than the comparison we’ve used here: babies born in the USA are twice as likely to die in their first year than babies in Japan, and the difference in average life expectancy between the USA and Sweden is three years, between Portugal and Japan it is over five years. Some comparisons are even more shocking: in 1990, Colin McCord and Harold Freeman in the Department of Surgery at Columbia University calculated that black men in Harlem were less likely to reach the age of 65 than men in Bangladesh.80
Among other things, our comparison between Baby A and Baby B shows that spending on health care and the availability of high-tech medical care are not related to population health. Figure 6.2 shows that, in rich countries, there is no relationship between the amount of health spending per person and life expectancy.
Figure 6.2 Life expectancy is unrelated to spending on health care in rich countries (currencies converted to reflect purchasing power).
THE ‘BIG IDEA’
If average levels of income don’t matter, and spending on high-tech health care doesn’t matter, what does? There are now a large number of studies of income inequality and health that compare countries, American states, or other large regions, and the majority of these studies show that more egalitarian societies tend to be healthier.10 This vast literature was given impetus by a study by one of us, on inequality and death rates, published in the British Medical Journal in 1992.81 In 1996, the editors of that journal, commenting on further studies confirming the link between income inequality and health, wrote:
The big idea is that what matters in determining mortality and health in a society is less the overall wealth of that society and more how evenly wealth is distributed. The more equally wealth is distributed the better the health of that society.82
Inequality is associated with lower life expectancy, higher rates of infant mortality, shorter height, poor self-reported health, low birthweight, AIDS and depression. Figures 6.3–6.6 show income inequality in relation to life expectancy for men and women, and to infant mortality – first for the rich countries, and then for the US states.
Of course, population averages hide the differences in health within any population, and these can be even more dramatic than the differences between countries. In the UK, health disparities have been a major item on the public health agenda for over twenty-five years, and the current National Health Service Plan states that ‘No injustice is greater than the inequalities in health which scar our nation.’83 In the late 1990s the difference in life expectancy between the lowest and highest social class groups was 7.3 years for men and
Figure 6.3 Life expectancy is related to inequality in rich countries.
Figure 6.4 Infant mortality is related to inequality in rich countries.
Figure 6.5 Life expectancy is related to inequality in US states.
Figure 6.6 Infant mortality is related to inequality in US states.
7 years for women.84 Studies in the USA often report even larger differences, such as a 28-year difference in life expectancy at age 16 between blacks and whites living in some of the poorest and some of the richest areas.85–87 To have many years’ less life because you’re working-class rather than professional – no one can argue about the serious injustice that these numbers represent. Note that, as the Whitehall study showed, these gaps cannot be explained away by worse health behaviours among those lower down the social scale.88–90 What, then, if the cost of that injustice is a three- or four-year shortening of average life expectancy if we live in a more unequal society?
We examined several different causes of death to see which had the biggest class differences in health. We found that deaths among working-age adults, deaths from heart disease, and deaths from homicide had the biggest class differences. In contrast, death rates from prostate cancer had small class differences and breast cancer death rates were completely unrelated to social class. Then we looked at how those different death rates were affected by income inequality, and found that those with big class differences were much more sensitive to inequality.8 We also found that living in a more equal place benefited everybody, not just the poor. It’s worth repeating that health disparities are not simply a contrast between the ill-health of the poor and the better health of everybody else. Instead, they run right across society so that even the reasonably well-off have shorter lives than the very rich. Likewise, the benefits of greater equality spread right across society, improving health for everyone – not just those at the bottom. In other words, at almost any level of income, it’s better to live in a more equal place.
A dramatic example of how reductions in inequality can lead to rapid improvements in health is the experience of Britain during the two world wars.91 Increases in life expectancy for civilians during the war decades were twice those seen throughout the rest of the twentieth century. In the decades which contain the world wars, life expectancy increased between 6 and 7 years for men and women, whereas in the decades before, between and after, life expectancy increased by between 1 and 4 years. Although the nation’s nutritional status improved with rationing in the Second World War, this was not true for the First World War, and material living standards declined during both wars. However, both wartimes were characterized by full employment and considerably narrower income differences – the result of deliberate government policies to promote co-operation with the war effort. During the Second World War, for example, working-class incomes rose by 9 per cent, while incomes of the middle class fell by 7 per cent; rates of relative poverty were halved. The resulting sense of camaraderie and social cohesion not only led to better health – crime rates also fell.
UNDER OUR SKIN
So how do the stresses of adverse experiences in early life, of low social status and lack of social support make us unwell?92 The belief that the mind affects the body has been around since ancient times, and modern research has enhanced our understanding of the ways in which stress increases the risk of ill-health, and pleasure and happiness promote wellbeing. The psyche affects the neural system and in turn the immune system – when we’re stressed or depressed or feeling hostile, we are far more likely to develop a host of bodily ills, including heart disease, infections and more rapid ageing.93 Stress disrupts our body’s balance, interferes with what biologists call ‘homeostasis’ – the state we’re in when everything is running smoothly and all our physiological processes are normal.
When we experience some kind of acute stress and experience something traumatic, our bodies go into the fight-or-flight response.93 Energy stores are released, our blood vessels constrict, clotting factors are released into the bloodstream, anticipating injury, and the heart and lungs work harder. Our senses and memory are enhanced and our immune system perks up. We are primed and ready to fight or run away from whatever has caused the stress. If the emergency is over in a few minutes, this amazing response is healthy and protective, but when we go on worrying for weeks or months and stress becomes chronic, then our bodies are in a constant state of anticipation of some challenge or threat, and all those fight-or-flight responses become damaging.
The human body is superb at responding to the acute stress of a physical challenge, such as chasing down prey or escaping a predator. The circulatory, nervous and immune systems are mobilized while the digestive and reproductive processes are suppressed. If the stress becomes chronic, though, the continual repetition of theses responses can cause major damage.
Chronic mobilization of energy in the form of glucose into the bloodstream can lead us to put on weight in the wrong places (central obesity) and even to diabetes; chronic constriction of blood vessels and raised levels of blood-clotting factors can lead to hypertension and heart disease. While acute momentary stress perks up our immune system, chronic continuing stress suppresses immunity and can lead to growth failure in children, ovulation failure in women, erectile dysfunction in men and digestive problems for all of us. Neurons in some areas of the brain are damaged and cognitive function declines.
We have trouble sleeping. Chronic stress wears us down and wears us out.
In this chapter we’ve shown that there is a strong relationship between inequality and many different health outcomes, with a consistent picture in the USA and developed countries. Our belief that this is a causal relationship is enhanced by the coherent picture that emerges from research on the psychosocial determinants of health, and the social gradients in health in developed countries. Position in society matters, for health and alternative explanations, such as higher rates of smoking among the poor, don’t account for these gradients. There are now a number of studies showing that income inequality affects health, even after adjusting for people’s individual incomes.94 The dramatic changes in income differences in Britain during the two world wars were followed by rapid improvements in life expectancy. Similarly, in Japan, the influence of the post-Second World War Allied occupation on demilitarization, democracy and redistribution of wealth and power led to an egalitarian economy and unrivalled improvements in population health.95 In contrast, Russia has experienced dramatic decreases in life expectancy since the early 1990s, as it moved from a centrally planned to a market economy, accompanied by a rapid rise in income inequality.96 The biology of chronic stress is a plausible pathway which helps us to understand why unequal societies are almost always unhealthy societies.
7
Obesity: wider income gaps, wider waists
Food is the most primitive form of comfort
The Spirit Level: Why Greater Equality Makes Societies Stronger Page 8