Does Inequality Make You Sick?
By Sally Satel and Theodore R. Marmor
Dr. Stephen Bezruchka, a physician with the University of Washington School of Public Health, has made the startling claim that income inequality is the major cause of our nation's health problems. Writing in Newsweek's My Turn column, he dismisses the role individuals can play in safeguarding their own well-being, claiming that "research during the last decade has shown that the health of a group is not affected substantially by individual behaviors such as smoking, diet and exercise." Better prescriptions for a healthy society, he argues, would include a "consumption tax."
Bezruchka is not alone in believing that improving health depends upon transforming economic conditions. Ichiro Kawachi of the Harvard School of Public Health, in his book Is Inequality Bad for Our Health?, declares income inequality an "important public health problem." Indeed, for the past decade public health experts have become increasingly eager to expand their professional agenda beyond health into broader controversies. In academia, combating inequities of all sorts has become a mission. According to Harvey V. Fineberg, former dean of the Harvard School of Public Health, "a school of public health is like a school of justice." At the National Institutes of Health, the Centers for Disease Control and Prevention, and health philanthropies such as the Robert Wood Johnson Foundation, research on health disparities related to race, ethnicity, and class—and the policy implications thereof—has expanded sharply. The American Public Health Association, too, has taken up far-flung political causes. Campaign finance reform, affirmative action, and the war in Nicaragua have been subjects of its policy statements. In 1996 the theme of the APHA's annual meeting was "Empowering the Disadvantaged: Social Justice in Public Health."
To be sure, attempts to understand the ultimate non-medical sources of ill health (e.g., education, class, deprivation) have occupied scholars for decades. But there is a huge difference between explicating these factors and claiming scientific authority for political remedies, as public health professionals such as Bezruchka believe is their charge. Indeed, fixating on social transformation as the proper role of public health professionals risks taking physicians and epidemiologists away from their traditional mission, or trivializing it. That mission is to develop the scientific and practical bases of disease prevention and to devise effective ways to educate the public about health risks. Misguided political activism is also demoralizing. Columbia University scholar Ronald Bayer, a contributing editor of the American Journal of Public Health's Policy and Ethics Forum, laments that so many of his colleagues believe "public health officials can do little or nothing to change the prevailing patterns of morbidity or mortality in the absence of social change." He dubs that mentality "public health nihilism."
None of this is to deny that social conditions, especially poverty, affect physical well-being and length of life. And public health practitioners do have a responsibility to design policies that reliably prevent disease, reduce contagion, and minimize injury. But they are sorely mistaken in thinking they have special expertise in changing the income distribution, in defining social justice, or in producing the instruments that can attain it.
A central premise of new public health scholarship is the "income-inequality" hypothesis. This hypothesis has spawned a minor academic industry, which has produced some important and carefully drawn epidemiological studies. It has also produced a surprising volume of ideologically driven speculation that fails to withstand critical scrutiny.
The hypothesis reached a wide audience in the early 1990s through the publications of Richard Wilkinson of the University of Sussex in England. Wilkinson claims the causal link between income inequality and individual health represents "the most important limitation on the quality of life in modern societies." From this he concludes there is "a persuasive case for the redistribution of income." Wilkinson and others point to data purporting to show that health and longevity are, in large part, determined by relative wealth. For example, wealthy countries with more equal income distributions, such as Sweden and Japan, have longer life expectancies than the United States.
Harvard's Kawachi, along with his colleague Bruce Kennedy and Norman Daniels, a philosopher at Tufts University, expand on Wilkinson's thesis. "The health of a population," they write, "depends not just on the size of the economic pie, but how the pie is shared." The authors speculate on how social inequality produces differences in health at each step on the socioeconomic ladder. "Income inequality," they observe, "appears to affect health by undermining civil society. . . . Lack of social cohesion leads to lower participation in political activity (such as voting, serving in local government, volunteering for political campaigns)." And lower participation, in turn, reduces government spending on public goods, such as education, and social safety nets.
Other public health scholars point to the disease-producing anxiety of not being able to keep up with the Joneses. As John W. Lynch and George A. Kaplan of the University of Michigan write, "health may be affected through individual appraisals of relative position in social order. Even those with good incomes might feel relatively deprived compared to the superrich."
There is in fact intriguing evidence that a person's socioeconomic position can affect health. Consider the landmark Whitehall studies led by Michael Marmot of University College in London. Marmot and his colleagues examined workers in the five grades of the British Civil Service; all had access to health care and at least a decent income. It was no surprise to the researchers that civil servants at the lowest grades suffered heart disease at about three times the rate of men at the top tier. But they were puzzled to discover that even highly paid professionals in the fourth category had twice as much heart disease as the workers right above them. What appeared to explain this finding was the fact that these workers had little "control of destiny"—their jobs were heavy with responsibility, but with relatively little authority.
Marmot did not presume to lead a social movement. Yet other scholars have done just that, using the Whitehall study as ammunition in their political crusade. "Illness is caused by the power imbalance in a capitalist society," insists Paula Braveman, a physician with the University of California at San Francisco. "We must counteract the free market with social programs," she told colleagues at an APHA meeting.
For those like Braveman who condemn capitalism, it is a small step to say that income inequality is the issue. Yet there are fundamental problems with the evidence upon which their arguments for the redistribution of income are based. First, consider the very measures of inequality typically cited—indices of income dispersion. "In practice, it is very difficult to distinguish the potential health effects of income inequality from the strong effects that arise from absolute need," says Harold Pollack, a policy researcher at the University of Michigan's School of Public Health. To those at the bottom of the economic ladder, it may be the ability to meet daily needs that matters most, not relative status. In this reading of the evidence, money is meaningful to the poor because of what it can buy, not because they have less of it than others. Thus, it is not so much income dispersion itself that matters for health but the proportion of the population that suffers true poverty-related problems, such as under-nourishment, lack of access to timely medical care, and so on.
In the United States, for example, the poverty level is higher than in northern Europe, where the social safety net has much finer mesh. The stunted longevity of poorer people pulls down the average life expectancy for our country. What's more, Pollack points out, the health impact of inequality itself is really unknown, once one controls for closely connected characteristics like race. What we are left with is energetic advocacy of a deeply uncertain claim about the connection between health and the degree of income inequality.
There are also dangers in concluding from the relationship between health and wealth that being less well-off produces disease. Indeed, the so-called healthy worker effect suggests an opposite reading: that health may determine income. After all, people who are healthier are more likely to hold jobs and to work competitively, activities that help them advance both their social and economic positions and, in turn, protect their health.
What's more, there may well be a third variable that is linked, independently, to health and socioeconomic success. "Individuals with great self-control and foresight may choose to acquire more education," explain Jeffrey Milyo and Jennifer Mellor, economists at the University of Chicago and William and Mary, respectively. "This heightened awareness of future outcomes could translate into both better earning potential and reduced propensities to engage in unhealthful behaviors such as smoking."
Last, there are some striking exceptions to the income-inequality schema. For instance, in Denmark, the gap between the top and bottom of the income scale is smaller than in the United States, yet its citizens have a lower average life expectancy than ours. The Japanese have the longest life expectancies, but their social hierarchy is very rigid. So much for sweeping generalizations about the longevity-threatening effect of a socially stratified society.
Even if the link between inequality and health were clearly established, the public health profession has no particular expertise in reducing inequality and solving broader problems of social injustice. Expending efforts in these directions diverts public health experts from proven strategies to better the health of the population—and there is much to do. Climbing rates of HIV/AIDS among minorities, epidemic levels of obesity, low rates of screening for cancer and high blood pressure—all of these call out for attention. While the opportunity to open a new front in the public debate over income distribution is seductive to some, it will siphon energies and resources from the vital issues that the public health profession has addressed so well in the past.