Introduction

Fact 1: If you are reading this in the United States of America, you have a much higher chance of dying than in any other high-income nation on Earth. This is true regardless of your age, gender, race, and yes, even income.^1,2

Fact 2: While having the worst health outcomes, the US also far outstrips its peers on healthcare expenditure.²

Any academic discussion of population health inevitably starts with two questions – what is it and why do I care? While we could opine on all the definitions and academic models proposed to define the term and the field, in our opinion, the two oxymoronic facts above synthesize it best.

This article is an introduction to some of the broad ideas that set this interdisciplinary field apart in its focus on health, shift away from healthcare, and innovative intersectoral collaborations to improve health at all levels. We start with a discussion on the state of population health in the United States. This will hopefully provide the reader a better understanding of the urgency of the situation and the why of population health.

We follow this up with a discussion of the multiple determinants that shape population health. We focus on the determinants that have been garnering the most interest from policymakers and payers alike, those that can be grouped under social determinants.

Finally, we round up the discussion with an introduction to the Health in All Policies (HIAP) approach to addressing some of the complex determinants of health, with a focus on the built environment. As we ponder possible solutions to the myriad and complex problems facing us as a society, a lot of our current issues seem to hit political and regulatory roadblocks in Mississippi. We hope that lessons from the HIAP framework inspire our local and state policy makers in placing health, if not at the center, at least within the boundaries of all policy decisions.

The State of Population Health in the United States

The state of population health in the United States is bad; it’s in dire need of resuscitation.

Before a more detailed discussion on this topic, it behooves one to define the term population health as used in this context. We find the Kindig and Stoddart framework of "population health as a concept of health" helpful in this case; they define population health as “the health outcomes of a group of individuals, including the distribution of such outcomes within the group.”³

This framework not only allows us to report population health as an aggregate measure, but also make comparisons across populations, which in this case is both across nations and within the US. Starting on a national level, the US performs very poorly compared to its high-income peers. In fact, the Commonwealth Fund report explicitly notes that “the U.S. is such an outlier that we have calculated the average performance based on the other 10 countries, excluding the U.S.” Of the 11 countries studied, the US ranks last overall, as well as last in four of the five domains evaluated – access to care, administrative efficiency, equity, and health care outcomes. As a reminder, at approximately 17%, the US has the highest healthcare spending as a percentage of GDP of all other high-income nations.²

The National Research Council report paints a similarly grim picture in a comparison of the US and 16 high-income peers. They reported that the US has a shorter life expectancy, the highest infant mortality rate, higher rate of deaths due to injuries and homicides, the highest rates of adolescent pregnancy, the highest incidence of AIDS, more numerous drug-related deaths, the highest rate of obesity, the second highest death rate from ischemic heart disease, and higher prevalence of chronic lung disease and disability compared to the peer nations.¹ It appears that population health in the US is unable to escape the scourge of devastating health outcomes across the spectrum of infectious and chronic diseases, all the way from cradle to grave.

Moving to a more granular level, in terms of the population evaluated, provides no respite. When comparing health and healthcare outcomes for women of reproductive age across high-income nations, the US has the highest rates of deaths from avoidable causes (including pregnancy-related complications); US women have significantly more problems paying their medical bills, delaying or skipping care because of costs and the highest rate of multiple chronic conditions and mental health needs.⁴ Men fare no better. When compared to their high-income peer nations, US men have the highest rates of avoidable deaths, chronic conditions, were most likely to skip or delay needed care because of cost, have problems paying medical bills and have one of the highest rates of mental health needs and out of pocket spending for healthcare. Unfortunately, the outcomes were worse for those with lower income and financial stress.⁵

While some of the above reports alluded to the unequal distribution of health outcomes within the US population based on income, the Centers for Disease Control and Prevention’s (CDC) National Center for Health Statistics (NCHS) published an in-depth analysis evaluating racial and ethnic health disparities. Within the US, non-Hispanic Black people have the shortest life expectancy at birth, non-Hispanic Black mothers had the highest percentage of preterm birth, experience the highest percentage of low-risk cesarean deliveries and children born to them have the highest rate of infant mortality. Hispanic and non-Hispanic Black children and adolescents have the highest rates of obesity and the adults of these demographics also have the lowest percentage of health insurance coverage.⁶

In summary, the state of population health in the United States is very poor and there is significant inequality and inequity in the distribution of these outcomes across racial and ethnic minorities and financially stressed individuals. To us, these facts stress the importance of evaluating the multiple, non-healthcare centric determinants that shape population health and form the focus of our discussion in the next section.

How Multiple Determinants Shape Population Health

A common refrain among those who work in clinical care, with all its attendant resources and infrastructure, is the baffling lack of even incremental improvements in their patients’ and communities’ health outcomes. Regardless of advances in pharmaceuticals or refinements in diagnostic technologies, they continue to be aghast at the persistently high number of patients they evaluate every year with stroke, heart failure, renal failure, sepsis, motor vehicle crashes and substance use disorders, to name just a few. Within hospitals and emergency departments there is occasionally a mention of someone not having a “safe discharge plan”, a euphemism for patients who are unhoused and uninsured, but that’s usually brushed aside as a flaw in the system and unimportant to the provider. To them, what happens outside the hospital, was, generally, unnecessary to learn or care about. After all, that’s what social workers manage.

More recently, especially in the past two decades in the US, medical providers and hospital administrators began to realize what population health scientists have been reporting on for a while - the relative importance and contribution of clinical care to overall population health. However, even now, new graduates, residents and physicians are neither taught, nor realize just how many upstream factors affect health, and how clinical care is of little significance in the broader context of population health. Based on one of the most widely used models of population health, the University of Wisconsin Population Health Institute’s County Health Rankings model, clinical care accounts for only 20% of health outcomes whereas social and economic factors and the physical environment account for almost 50%.⁷

Before a discussion on the social determinants, we wanted to briefly introduce two other broad determinants of health which, while being studied as separate, and important, academic fields of study, exert at least some of their impact through the social determinants and physical environment. The first is the commercial determinants of health (CDOH). The WHO defines them as “the private sector activities that affect people’s health positively or negatively” noting that the “private sector influences the social, physical and cultural environments through business actions and societal engagements; for example, supply chains, labour conditions, product design and packaging, research funding, lobbying, preference shaping and others”.⁸ In today’s world, the private sector plays a significant role in influencing health at all levels, and unlike governments that (hopefully) take a Health in All Policies (discussed later) approach, the private sector is usually "driven by a Profit in All Policies" approach.⁹ The second is the political determinants of health, often thought of as the determinant of determinants. They “involve the systematic process of structuring relationships, distributing resources, and administering power, operating simultaneously in ways that mutually reinforce or influence one another to shape opportunities that either advance health equity or exacerbate health inequities.”¹⁰ Not only do they influence a lot of social drivers that we discuss in the next section, but also have a huge impact on how these are distributed within a community, thus playing an significant role in health (in)equity.

Speaking of the social determinants of health (SDOH), the World Health Organization (WHO) defines them as “the conditions in which people are born, grow, work, live, and age, and the wider set of forces and systems shaping the conditions of daily life. These forces and systems include economic policies and systems, development agendas, social norms, social policies and political systems.”¹¹ Multiple determinants within the SDOH framework, such as housing, neighborhoods, food, income, education and employment have emerged as some of the most powerful drivers of health outcomes. While the US does spend outrageously more on healthcare than all its peer countries,² it is in the middle of the pack when it comes to social spending.¹² However, how it spends its social dollars has a much higher impact on the return of investment than the total dollars spent. Analysis of Organization of Economic Cooperation and Development (OECD) data reveals that the US allocates more resources to supporting older adults while spending significantly less on the social needs of families with young children and working-age adults.¹³ While decisions related to the relative allocation of resources to optimize population health run into the ethical challenges of valuing efficiency and equity,¹⁴ these factors, nevertheless, likely play an important role in determining the nation’s population health outcomes.

While there have been crucial, but disparate, efforts by individual physician groups, hospital systems, insurance companies and even health departments to address some health-related social needs (HRSN), the country has lacked a unified approach to the issues of HRSN or SDOH. Notably, and as a first, CMS issued guidance to all states last year to evaluate strategies to address SDOH to improve health outcomes of their beneficiaries. They noted that this would also lead to lower costs in the Medicaid and CHIP programs and augment their move towards a value-based payment system.¹⁵ The first of their five new priorities in their updated framework for health equity is “to improve our collection and use of comprehensive, interoperable, standardized individual-level demographic and social determinants of health (SDOH) data, including race, ethnicity, language, gender identity, sex, sexual orientation, disability status, and SDOH”, effective 2023.¹⁶

Hospital-based efforts can, at best, hope to manage just a few HRSN within the patient populations they serve. While laudable, and important, a lot more needs to be addressed contemporaneously to begin putting a dent in the social determinants that affect health inequity outside of HRSN.¹⁷ In the next section, we discuss one of the most comprehensive approaches to addressing the social determinants of health – the health in all policies approach.

Health in All Policies

The WHO defines HIAP as “an approach to public policies across sectors that systematically takes into account the health implications of decisions, seeks synergies, and avoids harmful health impacts in order to improve population health and health equity. It improves accountability of policymakers for health impacts at all levels of policy making. It includes an emphasis on the consequences of public policies on health systems, determinants of health, and well-being.”¹⁸ While not a new concept, it has lacked penetration at different levels of government, especially at the local level, where a lot of decisions that affect communities are made. The Public Health Institute and the American Public Health Association released a guide for local and state governments on how to use intersectoral collaborations as the basis of the HIAP approach. They note that this collaborative approach, “at its core, is an approach to addressing the social determinants of health that are the key drivers of health outcomes and health inequities.”¹⁹

While even a summary discussion of this topic is beyond the scope of this paper, the built environment provides an excellent framework to understand some of the concepts inherent to the HIAP approach to population health. The CDC notes that the built environment “includes the physical makeup of where we live, learn, work, and play—our homes, schools, businesses, streets and sidewalks, open spaces, and transportation options”.²⁰ These factors affect health in multiple ways – from how much physical activity we get during daily activities, the nutrient value of food at our local grocery stores, the level of crime and perceived safety in our neighborhood, stress associated with employment security to educational opportunities for our children, green spaces for them to play and socialize in and neighborhood support for the elderly, just to name a few.

Going back to the County Health Ranking Model and the relative importance of these factors to health outcomes, one immediately realizes the scope of collaboration needed across multiple non-medical sectors to improve the health of a population. Stakeholders would include urban planners involved in designing neighborhoods and roads, to improve walkability and bikeability, grocers to increase the availability of fresh produce, educators and caregivers involved in childcare centers and schools as well as policy makers at multiple levels to provide fiscal incentives (taxes, subsidies), permits for industries (air, water pollution and purification), zoning and other local laws and regulations. The HIAP approach ensures that lawmakers and regulators consider the health impacts of their decisions across all fields under their jurisdiction, especially those that were not traditionally associated with the medical field.

Conclusion

In summary, the state of population health in the US is poor, it is affected by multiple determinants with clinical care playing only a small role, and population health scientists need to advocate for a comprehensive intersectoral lens, as offered through the health in all policies approach, to begin ameliorating and shifting the curve of population health in the right direction. Physicians, population health scientists, public health officials, and politicians need to start thinking beyond the walls of the hospital or clinic and start taking a consequentialist approach to improving health.²¹