Socioeconomic Status, Principles, and Pragmatism: A Public Health of Consequence, June 2019

In 1995, Link and Phelan developed their theory of fundamental causes of health.¹ The theory aimed to explain why the link between socioeconomic status (SES) and health inequalities persist over time. To do so, the fundamental cause theory suggests that SES embodies a range of resources, including money, power, knowledge, prestige, and positive social connections, that generate health and that SES always has and always will do this as long as health is patterned on social and economic conditions. This explains why, for example, obesity was once associated with higher SES (when access to food was limited and eating more was a sign of affluence), whereas now it is associated with lower SES (because of the capacity of those with more resources to purchase healthier food).

Fundamental cause theory plays an important and central role in understanding the production of population health. At core, it positions economic inequalities as a foundational force that shapes a whole range of other opportunities and behaviors that then influence health. It also provides an elegant explanation for what is perhaps the most robust observation in all of population health: the association between resources and health, wherein those with more resources live longer and healthier lives.

THE FUNDAMENTAL CAUSE PARADOX

Fundamental cause theory presents a challenge of scale and perspective to anyone who is concerned with population health. Considering the centrality of foundational causes to the production of health, how much of our effort should be devoted to tackling foundational economic inequalities to promote health versus the more proximal causes, the behaviors and exposures that directly influence health?

Two articles in this issue of AJPH add to the literature about the central role that SES plays in shaping population health and push us to consider this question anew.

First, Myran et al. (p. 899) investigated the association between neighborhood SES and alcohol availability before and after the 2015 deregulation of the alcohol market in Ontario, Canada. This analysis found, perhaps unsurprisingly, that following deregulation, the number of alcohol outlets in Ontario increased. Even more so, however, low neighborhood SES was positively associated with increased alcohol access: lower SES neighborhoods had more alcohol outlets within 1000 meters. This greater access to alcohol in low SES neighborhoods then set the stage for greater alcohol harms in these neighborhoods and, one expects, widening health inequities between low and high SES groups.

Second, de Boer et al. (p. 927) assessed inequalities in health care costs in the Netherlands across neighborhood SES. They found a gradient in health care costs that was inversely associated with neighborhood SES. That is, the neighborhoods with the lowest SES had the highest health care costs. They calculated that health care costs would drop by 7.3% if all neighborhoods had the SES of the most affluent neighborhood, with the highest potential for reduction in costs among women aged 14 to 60 years.

At the most basic level, the articles by Myran et al. and de Boer et al. add analyses that further make the case for the foundational role that neighborhood SES plays in the production of health. However, in broader population health thinking, both articles push us to consider our priorities for action, asking us to consider what matters most² to improve population health.

TREATING THE ROOT CAUSE OR THE SYMPTOMS

Focusing on the particulars introduced by these articles, should we be developing alcohol-reduction education in Ontario to minimize the harms of alcohol use that may now accrue to low SES neighborhoods? Or should we be taking the time and monetary resources such an effort would entail and work to narrow SES inequalities? And, in the Netherlands, should we be developing interventions that aim to improve health care access, which would perhaps encourage better medication adherence to promote better health, or should we be working to narrow the foundational SES inequalities that are shaping the cost gap at the most foundational level?

The bounds of the answer to these questions can be set by two rather different approaches. At one end of the answer set, we can posit that any effort that does not tackle the foundational drivers of health, the fundamental causes of Link and Phelan’s theory, is a distraction and that we should focus our energies on tackling the economic inequalities that have always, with inevitability, shaped health inequalities. At the other end of the answer set, the very permanence of economic inequalities may suggest that focusing our efforts on underlying SES differences is an exercise in futility; SES gaps have always and likely will always exist, and so we should be focusing our energy on efforts that can mitigate the influence of these fundamental forces, on efforts to minimize the risks of alcohol when populations have access to it and perhaps on lifestyle modifications to minimize health care costs.

It seems to us that the right answer lies somewhere within the bounds of the potential answer set. We ignore fundamental causes at our peril: they ultimately shape the full set of behaviors and experiences that determine population health and efforts that inch us toward better grappling with fundamental causes, and they stand to yield substantial returns on our investment. However, focusing only on SES and its accompanying fundamental causes is a long-term commitment, one that will not resolve anytime soon (if ever), and we have a responsibility to help find shorter term solutions that can improve population health in the meanwhile. This, then, means that the right solution set is a matter of degree, a balance between engaging with the foundations and with the more proximal factors that shape health.

FINDING THE BALANCE

Understanding our task as one of finding such a balance can guide us on how we structure the scholarship of population health and the practice of public health. It suggests that we need scholarship about how to understand, and ameliorate, underlying foundational forces, and we need public health practice that engages in advocacy and foundational transformation. It also, however, calls for scholarship on more immediate solutions and a robust practice of public health that can mitigate foundational forces that have stood the test of time. This approach asks for a dexterous imagination and action across levels that defies simple characterization. It is, however, a principled but pragmatic approach that can help us best meet our responsibilities to the science of population health and the practice of public health.