Abstract
When the COVID-19 pandemic hit the United States in the spring of 2020, detailed analyses of infection rates revealed that African Americans and Latinos were more likely to contract the virus and more likely to die from it than whites. This fact made numerous media headlines. Even more was written about possible explanations—is it lack of testing, limited access to medical care, higher rates of underlying conditions, something about jobs, housing, neighborhoods? By July, it was also clear that the United States was handling the global pandemic worse than many other countries. Why did the richest country in the world end up having one of the highest COVID-19 infection rates? More generally, despite no difference in biological susceptibility, why are some countries and some demographic groups within countries more likely to be affected by a new disease than others? These are the kinds of questions Population Health in America, by Robert Hummer and Erin Hamilton, seeks to answer, proving its timeliness and relevance.
The introduction explains why and how health outcomes need to be considered from a population health perspective. Population health is defined as an interdisciplinary field that aims to document and explain patterns and trends in the health of people living in certain geographic areas. Drawing on their background as sociologists and demographers, the authors bring in “a specific social demographic perspective to the study of population health” (p. 9). Indeed, sociology’s preoccupation with social stratification and social context combined with demography’s attention to measurement and population representativeness provide a unique lens for studying population health. It is often assumed that health is determined primarily by individual-level factors, such as genetic background, health-related behavior (e.g., diet, exercise, smoking), and access to medical services. But the authors argue that focusing on individual-level factors alone—and designing public policies based on them—is insufficient. Understanding, for instance, why African Americans have higher mortality and often worse health outcomes than whites requires thinking about broad social forces that influence health above and beyond individual-level factors.
The first three chapters review historical trends in population health, discuss U.S. population health in the international perspective, and explain the importance of spatial (geographic) context, respectively. To gain readers’ attention and stimulate curiosity, each chapter begins with an engaging question or a puzzle. For example, we know that today people live longer and healthier lives than in the past. But how much healthier are Americans now than 100 years ago, asks Chapter One. When exactly did the improvements begin? What were specific factors responsible for the significant advances in population health in the past?
Some may know that despite spending more on health care than any other country in the world, Americans fare poorly in terms of health and mortality compared to people living in other developed countries, including some moderate-income states such as Costa Rica, Chile, and Slovenia. But few—at least based on the college students I teach—can explain why. The answer is admittedly a complicated one, but Chapter Two gives an excellent overview of the research findings on this topic.
Chapter Three documents the alarming differences in health outcomes by geography. For example, the estimated life expectancy in Fairfax County, Virginia, is 83.7 years, while it is only 73 years in Boone County, West Virginia. These differences are reduced but do not disappear once individual-level factors are accounted for, suggesting that there is something about places that matters. But what? States and counties can be different in so many ways, from climate to local policies. Neighborhoods embed multiple and interrelated social contexts. On top of that, people move in and out of areas for reasons that may or may not be related to their health. Despite these methodological challenges, insights from research on spatial differences in population health are critical for designing effective public health policies.
Subsequent chapters focus on the specific dimensions of social stratification—socioeconomic status, race/ethnicity, nativity, and gender. We know intuitively that higher socioeconomic status (SES) is associated with longer life and better health. We also know that racial and ethnic minorities typically have worse health outcomes than whites. The chapters unpack these associations by carefully describing the patterns and providing theoretical frameworks for understanding the existing health disparities as caused by multiple and interrelated social forces.
The last chapter discusses policy implications of population health science. Backed up by the evidence relayed in the previous chapters, it circles back to challenging the commonly held assumptions that health is primarily an outcome of individual actions and that access to medical care is the most important factor for maintaining good health. It turns out that targeting individual behavior is likely to exacerbate health inequalities because those who have more resources are better equipped to follow recommendations from public health and medical communities. Access to health care does little to prevent people from getting sick in the first place. That is why, the authors argue, we need policies that affect distribution of socioeconomic resources that influence individual health behavior and access to medical care. In fact, social and economic policies addressing unemployment, homelessness, poverty, segregation, and discrimination are key in promoting population health and reducing health inequalities.
There are many reasons to like this book. First, it reviews a large volume of past and current research on the topic. The 38-page bibliography includes key books, reports, and articles, easing an introduction to the field for novices. Second, the book is attuned to methodological issues related to data collection and interpretation of commonly used health indicators without being too technical. It is ideal for someone who does not have extensive training in demography or statistics. Third, writing about numbers can be challenging, but clear and elaborate explanations, graphs, diagrams, and vignettes make this book quite accessible, even for high school and undergraduate students. So does a detailed discussion of ongoing public health crises such as the obesity and opioid epidemics. Finally, throughout the book, the authors emphasize the policy implications of academic research on population health. Based on the current evidence, what are the best ways to promote population health and reduce health disparities? Even though it may take time and political will to implement these policies, there is hope that we will be better prepared for the next global pandemic.