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Inequality: Bad for Your Health
An interview with Ichiro Kawachi

This article is from the January/February 2008 issue of Dollars & Sense: The Magazine of Economic Justice, formerly available at http://www.dollarsandsense.org/archives/2008/0108kawachi.html

How do you stay healthy? That’s a no brainer, right? Eat the right foods, exercise, quit smoking, get regular medical checkups. Epidemiologist Ichiro Kawachi wants to add a new item to the list: live in a relatively egalitarian society. Kawachi, a professor of social epidemiology at the Harvard School of Public Health, has carried out a wide range of research studies on the social and economic factors that account for average health outcomes in different societies. Among the most novel conclusions of this body of research is that people in societies with high levels of economic inequality are less healthy than those living in more equal societies, regardless of their absolute levels of income.

Health policy is at least on the table in this election year. The conversation, however, is almost entirely limited to whether and how to ensure universal health insurance coverage. The work of Kawachi and his colleagues suggests that the public debate about health really needs to be much broader, encompassing a wide range of public policies—in many cases economic policies—that do not explicitly address health but that nonetheless condition how long and how robust our lives will be. Their work traces the multidimensional connection between an individual’s health and the qualities of her social world, many of which can shift dramatically when the gap between rich and poor widens.

Kawachi spoke with Dollars & Sense in November.

Dollars & Sense: Your research looks at the relationship between economic factors and health, especially whether living in a more unequal society, in itself, has a negative effect on health outcomes—and you have found evidence that it does. But I want to start by being really clear about what this hypothesis means. There seems to be such a complicated web of possible relationships between income and health.

Ichiro Kawachi: Let’s start with how your own income affects your health. Most obviously, income enables people to purchase the goods and services that promote health: purchasing good, healthy food, being able to use the income to live in a safe and healthy neighborhood, being able to purchase sports equipment. Income enables people to carry out the advice of public health experts about how to behave in ways that promote longevity.

But in addition to that, having a secure income has an important psychosocial effect. It provides people with a sense of control and mastery over their lives. And lots of psychologists now say that sense of control, along with the ability to plan for the future, is in itself a very important source of psychological health. Knowing that your future is secure, that you’re not going to be too financially stressed, also provides incentives for people to invest in their health Put another way, if my mind is taken up with having to try to make ends meet, I don’t have sufficient time to listen to my doctor’s advice and invest in my health in various ways.

So there are some obvious ways in which having adequate income is important for health. This is what we call the absolute income effect—that is, the effect of your own income on your own health. If only absolute income matters, then your health is determined by your income alone, and it doesn’t matter what anybody else makes. But our hypothesis has been that relative income might also matter: namely, where your income stands in relation to others’. That’s where the distribution of income comes in. We have looked at the idea that when the distance between your income and the incomes of the rest of society grows very large, this may pose an additional health hazard.

D&S: How could people’s relative income have an impact on health, even if their incomes are adequate in absolute terms?

IK: There are a couple of possible pathways. One is this ancient theory of relative deprivation: the idea that given a particular level of income, the greater the distance between your income and the incomes of the rest of society, the more miserable you feel. People are sensitive to their relative position in society vis-à-vis income. You may have a standard of living above the poverty level; nonetheless, if you live in a community or a society in which everyone else is making so much more, you might feel frustrated or miserable as a result, and this might have deleterious psychological and perhaps behavioral consequences. So that’s one idea.

Another hypothesis about why income distribution matters is that when the income or wealth gap between the top and bottom grows, certain things begin to happen within the realm of politics. For example, when the wealthiest segment of society pulls away from the rest of us, they literally begin to segregate themselves in terms of where they live, and they begin to purchase services like health care and education through private means. This translates into a dynamic where wealthy people see that their tax dollars are not being spent for their own benefit, which in turn leads to a reduced basis for cooperation and spending on public goods. So I think there is an entirely separate political mechanism that’s distinct from the psychological mechanism involved in notions of relative deprivation.

These are some of the key ways in which income inequality is corrosive for the public’s health.

D&S: When you talk about relative deprivation, are you talking primarily about poor people, or does the evidence suggest that inequality affects health outcomes up and down the income ladder? For instance, what about the middle class? I think for the public to understand the inequality effect as something different from just the absolute-income effect, they would have to see that it isn’t only poor people who can be hurt by inequality.

IK: Exactly, that’s my argument. If you subscribe to the theory that it’s only your own income that matters for health, then obviously middle-class people would not have much to worry about—they’re able to put food on the table, they have adequate clothing and shelter, they’re beyond poverty. What the relative-income theory suggests is that even middle-class people might be less healthy than they would be if they lived in a more egalitarian society.

D&S: That’s what I was wondering about. Say we compared a person at the median income level in the United States versus Germany, both of whom certainly have enough income to cover all of the basic building blocks of good health. Would this hypothesis lead you to expect that, other things being equal, the middle-income person in the United States will likely have worse health because economic inequality is greater here?

IK: Yes, that’s exactly right. And that’s borne out. Americans are much less healthy than Europeans, for example, in spite of having higher average wealth.

D&S: But, unlike most other rich countries, the United States does not have universal health care. Couldn’t that explain the poorer health outcomes here?

IK: Not entirely. There was a very interesting paper that came out last year comparing the health of Americans to the health of people in England, using very comparable, nationally representative surveys. They looked at the prevalence of major conditions such as heart attack, obesity, diabetes, hypertension. On virtually every indicator, the top third of Americans by income—virtually all of whom had health insurance—were still sicker than the bottom third of people in England. The comparison was confined to white Americans and white Britons, so they even abstracted out the contribution of racial disparities.

Health insurance certainly matters—I’m not downgrading its importance—but part of the reason Americans are so sick is because we live in a really unequal society, and it begins to tell on the physiology.

D&S: Has anyone tried to compare countries that have universal health care but have differing levels of inequality?

IK: There have been comparisons across Western European countries, all of which pretty much have universal coverage. If you compare the Scandinavian countries against the U.K. and other European countries, you generally see that the Scandinavians do have a better level of health. The more egalitarian the country, the healthier its citizens tend to be. But that’s about as much as we can say. I’m not aware of really careful comparative studies; I’m making a generalization based on broad patterns.

D&S: It sounds like there is still plenty of research to do.

IK: Yes.

D&S: You have already mentioned a couple of possible mechanisms by which an unequal distribution of income could affect health. Are there any other mechanisms that you would point to?

IK: I think those are the two big ones: the political mechanism, which happens at the level of society when the income distribution widens, and then the individual mechanism, which is the relative deprivation that people feel. But I should add that relative deprivation itself can affect health through a variety of mechanisms. For instance, there is evidence that a sense of relative deprivation leads people into a spending race to try to keep up with the Joneses—a pattern of conspicuous, wasteful consumption, working in order to spend, to try to keep up with the lifestyle of the people at the top. This leads to many behaviors with deleterious health consequences, among them overwork, stress, not spending enough time with loved ones, and so forth.

Very interestingly, a couple of economists recently analyzed a study of relative deprivation, which used an index based upon the gap between your income and the incomes of everybody above you within your social comparison group, namely, people with the same occupation, or people in the same age group or living in the same state. What they found was that the greater the gap between a person’s own income and the average income of their comparison group, the shorter their lives, the lower their life expectancy, as well as the higher their smoking rates, the higher their utilization of mental health services, and so on. This is suggestive evidence that deprivation relative to average income may actually matter for people’s health.

D&S: It’s interesting—this part of your analysis almost starts to dovetail with Juliet Schor’s work.

IK: Absolutely, that’s right. What Juliet Schor writes about in The Overspent American is consumerism. It seems to me that in a society with greater income inequality, there’s so much more consumerism, that the kind of pathological behavior she describes is so much more acute in unequal societies, driven by people trying to emulate the behavior of those who are pulling away from them.

D&S: Your research no doubt reflects your background as a social epidemiologist. However, it seems as though many mainstream economists view these issues completely differently: many do not accept the existence of any causal effect running from income to health, except possibly to the degree that your income affects how much health care you can purchase.

IK: Yes, there is a lot of pushback from economists who, as you say, are even skeptical that absolute income matters for health. What I would say to them is, try to be a little bit open-minded about the empirical evidence. It seems to me that much of the dismissal from economists is not based upon looking at the empirical data. When they do, there is a shift: some economists are now beginning to publish studies that actually agree with what we are saying. For example, the study on relative deprivation and health I mentioned was done by a couple of economists.

Another example: some studies by an erstwhile critic of mine, Jeffrey Milyo, and Jennifer Mellor, who in the past have criticized our studies on income distribution and health in the United States as not being robust to different kinds of model specifications—a very technical debate. Anyway, most recently they published an interesting study based on an experiment in which they had participants play a prisoners’ dilemma kind of game to see how much they cooperate as opposed to act selfishly. One of the things Mellor and Milyo found was that as they varied the distribution of the honoraria they paid to the participants, the more unequal the distribution of this “income,” the more selfishly the players acted. They concluded that their results support what we have been contending, which is that income inequality leads to psychosocial effects where people become less trusting, less cohesive, and less likely to contribute to public spending.

D&S: That’s fascinating.

IK: Yes, it’s very interesting. So watch this space, because some of the recent evidence from economists themselves has begun to support what we’re saying.

D&S: In other parts of the world, and especially in Africa, there are examples of societies whose economies are failing or stagnating because of widespread public health issues, for example HIV/AIDS. So it seems as if not only can low income cause poor health, but also that poor health can cause low income. I wonder if your research has anything to say about the complicated web between income and health that those countries are dealing with.

IK: There’s no doubt that in sub-Saharan Africa, poor health is the major impediment to economic growth. You have good econometric studies suggesting that the toll of HIV, TB, and malaria alone probably slows economic growth by a measurable amount, maybe 1½ percentage points per year. So there’s no question that what those countries need is investment to improve people’s health, in order for them to even begin thinking about escaping the poverty trap. The same is true in the United States, by the way. Although I’ve told the story in which the direction of causation runs from income to health, of course poor health is also a major cause of loss of income. When people become ill, for example, they can lose their jobs and hence their income.

What I’ll say about the developing world is that in many ways, the continuing lack of improvement in health in, for example, the African subcontinent is itself an expression of the maldistribution of income in the world. As you know, the rich countries are persistently failing to meet the modest amount of funding that’s being asked by the World Health Organization to solve many of these problems, like providing malaria tablets and bed nets and HIV pills for everyone in sub-Saharan Africa. If you look at inequality on a global scale, the world itself could benefit from some more redistribution. Today the top 1% of the world’s population owns about a third of the world’s wealth. So, although certainly the origins of the HIV epidemic are not directly related to income inequality, I think the solution lies in redistributing wealth and income through overseas development aid, from the 5% of the world who live in the rich countries to everyone else.

D&S: Leaving aside some of the countries with the most devastating public health problems, poor countries in general are often focused just on economic growth, on getting their per capita GDP up, but this often means that inequality increases as well—like in China. Do you view the inequality effect as significant enough that a developing country concerned about its health outcomes should aim to limit the growth of inequality even if that meant sacrificing some economic growth?

IK: It depends on the country’s objectives. But I’d ask the question: what is the purpose of economic growth if not to assure people’s level of well-being, which includes their health? Why do people care about economic growth? In order to lead a satisfying and long life, many people would say. If that’s the case, then many people living in developing countries may feel exactly as you suggest: they would prefer policies that attend to egalitarian distribution over policies that are aimed purely at growth.

Amartya Sen has written about this; he has pointed to many countries that are poor but nonetheless enjoy a very good level of health. He cites examples like Costa Rica and the Kerala region in India, which are much, much poorer than the United States but enjoy a high level of health. It really depends on the objectives of the country’s politicians. In Kerala and Costa Rica, their health record is very much a reflection of how their governments have invested their income in areas that promote health, like education and basic health services—even if doing so means causing a bit of a drag on economic growth.

China also had this record until perhaps ten years ago. Now they’re in this era of maximizing growth, and we’re seeing a very steep rise in inequality. Although we don’t have good health statistics from China, my guess is that this is probably going to tell on its national health status. Actually, we already know that improvement in their child mortality rates for children under five has begun to slow down in the last 20 years, since the introduction of their economic reforms. In the 1950s and 1960s, the records seemed to suggest quite rapid improvements in health in China. But that’s begun to slow down.

D&S: Certainly your research on the health effects of inequality could represent a real challenge in the United States in terms of health care policy. In many ways we have a very advanced health care system, but many people are not well served by it. What effect do you think your work could or should have on U.S. health policy?

IK: Regardless of whether you believe what I’m saying about income inequality, the most basic interpretation of this research is that there are many things that determine people’s health besides simply access to good health services. We spend a lot of time discussing how to improve health insurance coverage in this country. In the current presidential debates, when they talk about health policy, they’re mostly talking about health insurance. But it’s myopic to confine discussions of health policy to what’s going to be done about health insurance. There are many social determinants of health and thus many other policy options for improving Americans’ health. Investing in education, reducing the disparities in income, attacking problems of poverty, improving housing for poor people, investing in neighborhood services and amenities—these are all actually health policies. The most fundamental point about this whole area of research is that there are many determinants of health besides what the politicians call health policy.

D&S: Besides doctors and medical care.

IK: Yes, that’s right. I used to be a physician, and physicians do a lot of good, but much of health is also shaped by what goes on outside the health care system. That’s probably the most important thing.

The second thing is the implication that income certainly matters for health. So policies that affect peoples’ incomes, both absolute and relative income, may have health consequences. For instance, I think the kinds of tax policies we have had in recent years—where most of the benefits have accrued to the top 1% and the resulting budget deficits have led to cutbacks of services to the rest of us, especially those in the bottom half of the income distribution—have been a net negative for public health, through the kind of political mechanism I have described.

D&S: It’s almost as though there should be a line for health care in the cost-benefit analysis of any change in tax policies or other economic policies.

IK: Absolutely. There’s an idea in public health called the health impact assessment. It’s a technique modeled after environmental impact assessments, a set of tools that people are advocating should be used at the Cabinet level. The idea is that when, say, the treasury secretary suggests some new economic measure, then we can formally put the proposal through a modeling exercise to forecast its likely effects on health. Health certainly is very sensitive to decisions that are made elsewhere in the Cabinet besides what goes on in Health and Human Services.

D&S: What about global health policy? Are groups like the World Health Organization paying attention to the kind of research that you do?

IK: Yes, they are. Maybe seven or eight years ago, the WHO had a commission on macroeconomics and health, headed by Jeffrey Sachs. The idea was, by increasing funding to tackle big health problems in the developing world, we can also improve their economic performance and end poverty. That commission posed the direction of causality from health to income. In the last three years, the WHO has had a new commission on the social determinants of health, headed by a social epidemiologist from England, Michael Marmot. That group is looking at the other direction of causality—namely, from poverty to ill health—and considering the ways in which government policies in different areas can improve people’s social environment in order to improve their health. I think they are due to report next year with some recommendations as well as case examples from different countries, mostly developing countries whose governments have tried to tackle the economic side of things in order to improve health outcomes.

D&S: Right now the United States is continuing on this path of becoming more and more economically stratified. Your work suggests that that doesn’t bode well for us in terms of health. I wonder—this is very speculative—but if we stay on this path of worsening inequality, what do you predict our health as a country is likely to look like in 20 or 30 years?

IK: We’re already in the bottom third of the 23 OECD countries, the rich countries, in terms of our average health status. Most people are dimly aware that we spend over half of the medical dollars expended on this planet, so they assume that we should therefore be able to purchase the highest level of health. I teach a course on social determinants of health at Harvard, and many of my students are astonished to discover that America is not number one in life expectancy.

I predict that if we continue on this course of growing income inequality, we will continue to slip further. That gains in life expectancy will continue to slow down. Life expectancy is increasing every year, probably because of medical advances, but I suspect that eventually there will be a limit to how much can be delivered through high-tech care and that our health will slip both in relative terms, compared to the rest of the OECD countries, and maybe even in absolute terms, losing some of the gains we have had over the last half century. For example, some demographers are already forecasting that life expectancy will drop in the coming century because of the obesity academic. Add that to the possible effects of income inequality, and I could easily imagine a scenario in which life expectancy might decline in absolute terms as well as in relative terms. It’s likely that we have not yet seen the full impact of the recent rise in inequality on health status, because it takes a while for the full health effects to become apparent in the population.

The interview was conducted by D&S co-editor Amy Gluckman and intern Alissa Thuotte.

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