This issue of The Milbank Quarterly begins with an article that comprehensively examines one of the most provocative ideas to emerge from social epidemiology in recent years: the possibility that income inequality affects the health of populations. An inverse relationship between income and many measures of morbidity and mortality has long been recognized, but in the 1980s and early 1990s, epidemiologists began to explore the role of income inequality on the health of populations. In one of the most widely cited studies on this topic, Richard Wilkinson (1992) examined data from nine industrialized countries and found a very strong relationship between the degree of income inequality in countries and life expectancy.

The possibility that income inequality has important consequences for the health of populations attracted much attention in both policy and research circles. A large research literature developed on the topic. In their article, “Is Income Inequality a Determinant of Population Health? Part 1. A Systematic Review,” John Lynch, George Davey Smith, Sam Harper, Marianne Hillemeier, Nancy Ross, George Kaplan, and Michael Wolfson provide a critical review and assessment of the theoretical and empirical work on the income inequality–health hypothesis. In part 2, which will be published in a future issue of the Quarterly, they will present a new research strategy and use national and regional trends of cause-specific mortality in the United States to examine this question.

In the article in this issue, Lynch and colleagues trace the development of the income inequality–health hypothesis and describe the different versions that various researchers have offered, as well as the mechanisms by which income inequality could affect health. In tabular form, they summarize 98 studies of income inequality and health across and within countries over the past 25 years. These studies have focused on different populations, used different measures of inequality and health, employed different analytic strategies, and tested different versions of the income inequality–health hypothesis. In addition to summarizing these studies, the authors tackle the more challenging problem of making sense of this corpus of seemingly inconsistent and contradictory data. They provide a rich discussion of methodological issues and cross-national differences, including the puzzle of why associations have been found between income inequality and mortality in some countries but not in others. Their discussion of “American exceptionalism”—the possibility that the income inequality–health relationship is particularly strong in the United States—is a precursor to their forthcoming article, which will offer new empirical data on that question.

Based on their literature review, Lynch and his colleagues conclude that there is little evidence that income inequality is a “major, generalizable determinant” of differences in population health among or within rich countries, but they also note evidence that income inequality does contribute to some health outcomes (notably homicides) in some contexts. They stress that these conclusions do not contradict the large body of evidence of a positive association between income and health at the individual level.

In the second article in this issue, Hilary Graham focuses on a different aspect of health disparities. In “Social Determinants and Their Unequal Distribution: Clarifying Policy Understandings,” Graham looks at a trend in recent governmental public health policy documents from industrialized countries. She observes a common, potentially confusing aspect of the stated policy goals in these documents. Improving population health and reducing disparities in health are often cited as goals of public health policy, and addressing the social determinants of health is proposed as a path toward achieving both. However, Graham points out that the social determinants of health are not necessarily the same as the causes of disparities in health. Thus, strategies aimed at improving population health could worsen these disparities even while improving the population’s overall health. The goal of reducing health inequalities is best pursued by strategies focused on the social determinants of such inequalities, Graham argues, not by strategies aimed at improving population health.

The third article in this issue examines an often overlooked social mechanism affecting morbidity and mortality: the law. In “Addressing the ‘Risk Environment’ for Injection Drug Users: The Mysterious Case of the Missing Cop,” Scott Burris and his colleagues examine how the legal system interacts with the culture, sociology, and psychology of injection drug users to result in behavior that increases the risk of transmitting diseases such as HIV/AIDS. Concentrating on how social, political, and economic factors and the physical environment interact with personal characteristics to determine health, Burris and his colleagues show the many ways that the legal system influences the world of injection drug users in ways that produce more risky behavior. The authors call for a public health research and intervention agenda that includes the law, enforcement agencies, and frontline officers, as well as injection drug users.

In “Changes in Elderly Disability Rates and the Implications for Health Care Utilization and Cost,” Brenda Spillman offers new data on an important question for health and social policy in the United States as the size of the elderly population grows: What services related to disability will this population require? Spillman uses data from the 1984, 1989, 1994, and 1999 National Long-Term Care Surveys to estimate trends in disability among older Americans. As she notes, several recent studies have reported that age-adjusted chronic disability has been declining, a finding with favorable implications for health care costs. Spillman disaggregates the components of the decline in disability. She finds that on an age-adjusted basis, the main improvements have been on activities (such as financial management and shopping) that have minimal health cost implications but that reliance on assistive devices has increased and institutional residence has remained stable. Spillman suggests that gains in independence that result from environmental improvements rather than from better health may have no positive implications for health care costs.

This issue concludes with Rebecca Dresser’s article, “Genetic Modification of Preimplantation Embryos: Toward Adequate Human Research Policies.” Dresser examines whether the rules that govern research in the United States are adequate for likely developments in the field of genetics. She looks at the ethical and policy issues that might arise in research involving the genetic modification of human embryos. She discusses several novel issues related to such research that are not adequately dealt with by current federal regulations to protect human subjects, including the possibility that multiple generations could be affected. Her article includes policy recommendations to ensure that research involving the genetic modification of embryos meets accepted standards for human subjects research.

Readers may notice a change on the masthead of the Quarterly, which for many years has carried the subtitle “A Journal of Public Health and Health Care Policy.” With this first issue of Volume 82, that subtitle now reads “A Multidisciplinary Journal of Population Health and Health Policy.” This modification in the description of the Quarterly’s content is not intended to signal a change of purpose but to convey more clearly and accurately the Quarterly’s focus. The term public health has increasingly come to connote a relatively narrow, though vitally important, set of activities that are carried out by agencies with official functions. The Milbank Quarterly is concerned with a very broad range of topics affecting health, as this current issue well illustrates. The term public health has increasingly seemed too confining. (It is noteworthy that the title of a recent Institute of Medicine report [2002] about assuring the future health of the American people contains the term the public’s health rather than public health.) The term population health has been increasingly used in recent years, probably because it suggests a broad set of concerns—a particular perspective—rather than a specific set of activities, actors, or approaches. Thus, population health is more descriptive of the content to which the Quarterlyaspires than public health is.

The reasons for the other two changes in the journal’s subtitle are simpler. The phrase health policy is a broader and thus more appropriate term than health care policy, and including the word multidisciplinary might help potential authors and readers identify better the type of work that the journal publishes.

Bradford H. Gray
Editor, The Milbank Quarterly

Institute of Medicine. 2002. The Future of the Public’s Health in the 21st Century. Washington, D.C.: The National Academies Press.

Wilkinson, R.G. 1992. Income Distribution and Life Expectancy. BMJ 304(6820):165—8.

Author(s): Bradford H. Gray

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Volume 82, Issue 1 (pages 1–4)
DOI: 10.1111/j.0887-378X.2004.00301.x
Published in 2004