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The United States spends far more on medical care than any other nation in the world. Yet its health outcomes have for some time consistently ranked at or near the bottom among affluent nations and even worse than some low-income countries.1 Furthermore, within the United States, levels of health vary dramatically across states, localities, and different social and economic groups,2 in patterns that are not explained by differences in medical care. The Scottish physician Thomas McKeown critically examined the widespread assumption that medical care is responsible for the dramatic decline in mortality that occurred in the United States and other affluent countries in the first half of the twentieth century. Using data from the United Kingdom and Wales, he demonstrated for multiple causes of death that the steep reductions in mortality were well under way decades before the availability of effective modalities of modern medicine, such as antibiotics and intensive care units.3 Substantial disparities in health across different socioeconomic groups are seen even within countries that provide financial access to medical care for the entire population.4,5 These and numerous other findings have led many observers to question the widely prevalent assumption that medical care is the most important modifiable influence on health.
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The term “social determinants of health” has been used primarily to refer to the factors outside of medical care that are important influences on health and at least in theory could be influenced by social policy. There is a prominent exception, however, which may be a source of confusion. The World Health Organization’s Commission on the Social Determinants of Health (2005–08) included medical care among the “social determinants.” This was presumably out of concern that many resource-poor countries lack even the most rudimentary medical care systems, which, if implemented, could dramatically, rapidly, and at low cost improve the health of their populations; the reasoning may have been that, given that medical care is determined by social policies, it would be a mistake to omit it from the agenda for “social determinants.” Outside of this exception, “social determinants of health” have referred to nonmedical factors. In the affluent countries (e.g., western Europe, the United States, Canada, Australia, and Japan), by contrast, medical care has for many decades been far more developed; a focus on the social determinants of health has been in part a response to the tendency for medical care to consume ever-increasing percentages of national budgets in affluent countries, without concomitant improvements in health status.
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Despite the mounting evidence of the importance of nonmedical determinants of health, “health” is still often equated with “healthcare”; the terms are often used virtually interchangeably. Since the 1960s or 1970s, there has been public awareness of the powerful health effects of health-related behaviors such as diet, exercise, smoking, and alcohol and drug consumption. The major initiatives to improve health in the United States have focused either on improving access to or quality ...