The future of public health in the United States is difficult to predict, but the challenges public health has yet to overcome are much more certain.
As Keck, Scutchfield, and Holsinger point out in their concluding chapter of Contemporary Public Health, “one of the few constants in public health practice is that change is ongoing and increasingly rapid”. A great challenge, therefore, will be to complete the transformational process of reimagining public health’s scope and realigning her efforts in light of the social determinants of health. The same authors describe this new frontier as a “perplexing mission”, and I’d add that this mission is into territories alien and potentially unfriendly to public health’s intercession.
This perplexing mission into new frontiers, however difficult or resisted, is absolutely necessary. It’s becoming ever clearer that, just as the dramatic gains in life and health during the last century are attributable to broadly defined public health activities, any further such gains can only come through new public health strategies and policies grounded in social justice, health equity, and primordial prevention that directly address the social determinants of health. We now know what these new, necessary targets look like: “economic opportunity, early childhood development, structural racial biases, education, housing, the workplace, community design, nutrition”, and others. But what, exactly, do issues like financial insecurity or institutionalized racism have to do with health? More fundamental than what public health’s strategies should be regarding them, why are these and similar issues being referred to as health’s social determinants in the first place?
To answer that, let’s first identify a class of intermediate health determinants with which we are already familiar: Behavior. We know that a great proportion of deaths (38%) can be attributed to behavioral factors (such as tobacco use, poor diet, lack of physical activity and exercise, and alcohol consumption). For example, the immediate cause of death in a hypothetical case might be a heart attack, but we know that the underlying cause of that heart attack is likely to be long-term cigarette smoking by the victim. But this causal chain can be traced back even further. The numbers can sometimes be misleading, and the truth often counterintuitive, but a growing body of high-quality evidence has been telling us – and we are beginning to admit – that the upstream forces that shape such behaviors as cigarette-smoking are more broadly influential, more uniformly and efficiently changed, and therefore better targets for our attempts to intervene. By directing our efforts and resources at the macro-, physical, and social environments, we are likely to help more people more consistently and effectively for far greater benefit than we do now, focused as we are on treating the harms imposed by these environments.
How has this picture of social determinants of health status and outcomes emerged? The Whitehall study during the 1970s was among the first, corroborated by many others since, to document the correlation between social class, occupation, and income on the one hand, and health outcomes on the other. Those below the poverty line, we now know, are five times more likely to be in poor physical and psychological health than those at or above median income.
But theories are only as good as the predictions derived from them. How accurately does this theory of the health determinism of society’s configuration reflect reality? Let’s test it in a simple case: social determinants theory, given the fact that average income in the US has been declining since 1999, would predict a concomitant decline in life expectancy, which has, in fact, occurred. Social determinants theory would similarly predict, given that the US’s Gini coefficient, which is a measure of income inequality within a given society, has been increasing since 1968, an increase in health disparity over the same period, which has also occurred. By now, thousands of studies from all over the world have contributed to social determinants theory and evidence, and all over the world, similar predictive power is confirmed. This theory’s relevance is not just for those at extremes of social disadvantage – quiet the contrary. Rather, there is a clear dose-response relationship between income and wealth, and an individual’s health. Health flows down the gradient of social and economic status – a linear correlation from which few in society escape, and none are exempt.
Woolf and Braveman, in addressing the interplay between the ecological determinants of health (i.e., the social and physical environments) and the health status of individuals and groups, note the 2003 landmark report “Unequal Treatment” as having drawn attention to racial and ethnic minority treatment in healthcare delivery. We now know that socioeconomic status is but one axes of health determinants. Minority status is an overlapping, but distinct axes of its own. Being poor is bad for your health, but not as bad, on average, as being a poor member of a racial minority. Worse yet, being a poor and uneducated member of a racial minority. These independent variables – wealth or income, educational attainment (itself influenced by the first), racial and ethnic or minority status, and many others – are in some cases additive, but in many appear multiplicative in their effects over a lifetime on health status and outcomes of illness and injury.
UNICEF has reported that the percentage of children living in families with income less than 50% of their nation’s median is highest in the US among OECD nations. All other OECD nations also have stronger safety nets, contributing a larger portion of their tax base to programs for unemployed, maternal & child services, welfare assistance, education, job training, and employment benefits. All nations must deal with the reality that the health of their population is fundamentally determined by their macro-, physical, and social environments. Unfortunately, the US lags far behind her peer nations in aligning her policies with this fact.
As Woolf and Braveman put it, “Education and income are elements of a complex web of interwoven social and economic conditions that exert health effects over a lifetime.” Though we are still teasing out these conditions, their relationships, and their full long-term effects, we know enough to be certain that the new targets of public health, and even medicine, if any further progress of the kind which characterized the golden age of dramatic health improvements during the 20th century is to be realized, must be far upstream of disease (where, unfortunately, the vast majority of our current energies are aimed), at the fundamental social determinants of health and disease for all of us, themselves.