Multilevel Thinking and Life Course Perspectives Inform Public Health Practice: A Public Health of Consequence, November 2018

The science of population health and the practice of public health rest heavily on empiricism: they draw on data from research to explicate what affects population health and to inform public health practitioners of what to do to improve public health. To this end, science’s role is front and center, as it should be, and with science we can build the programs of and actions taken by public health. We sometimes, perhaps inadvertently, downplay or minimize the role of theory in how we think about what influences population health and how we should approach these influences. Despite some excellent work articulating the theories that could guide our work in population health science,¹ much of our scholarship and practice remains explicitly atheoretical: we publish on what we observe; we do what we think works.

The challenge this approach presents—as leading theorists in the field amply note—is that all our efforts are ultimately informed by some perspective, whether we are explicit about it or not.^2,3 If we fail to build our work on clearly articulated theoretical frameworks, we run the risk of allowing implicit biases and orientations to influence what we do and how we do it. At best, this minimizes our efficiency; at worst it creates the risk of our actions having unintended consequences.

MULTILEVEL AND LIFE COURSE FRAMEWORKS

Multilevel and life course frameworks are, to our minds, two of the most important theoretical lenses to come to maturity over the past two decades; both can inform, and improve, population health science and public health practice. It is beyond the scope of this brief editorial to fully discuss these perspectives; however, by way of brief summary, a multilevel perspective—having much in common with ecosocial and social ecological frameworks—suggests that health is explicitly and inextricably linked to the context around us. This context shapes the air we breathe, the food we eat, and how we behave—all of which are proximal drivers of individual health.⁴

It is therefore imperative to know what the different levels of context are—which include national-level policies, municipal actions, neighborhoods, social networks, and individual behavior—and to understand how they interact to generate population health effects. Perhaps an obvious example is that it is now lingua franca in public health to recognize that alcohol outlet policies at the group level influence population-level alcohol use and its consequences.⁵

A life course perspective suggests that an individual’s present health was shaped and produced by the individual’s health over the life course and that health is even transmitted intergenerationally.⁶ This framing suggests that when we focus on health at any particular point in time, our understanding of what affects health is limited. We must take into account the forces that generated the conditions of health even if these forces have receded. Conversely of course, this perspective urges us to consider the health consequences of present actions, to recognize that decisions made today—for instance, regarding forces that influence global environmental climate change—will have health implications in coming decades.⁷

These two perspectives are, when properly understood, transformative to our work, and they substantially influence how we should conduct our scholarship and choose to act to improve public health. We highlight an article in this month’s issue of AJPH that nicely illustrates the first half of this essential pair; multilevel thinking.

THE FRAMEWORKS IN ACTION

Block et al. (p. 1550) explore how residential crowding and commute time influence early child development. Using data on more than 180 000 US children in 2793 census tracts over seven years, this study shows that crowding is associated with decreases in child cognitive development and communication skills and that in high-poverty subsamples, commute time is associated with decreases in social competence and emotional maturity. This study demonstrates elegantly a relationship between the urban environment and child health. In particular it shows how features of child development—cognitive development and social competence—will have long-term consequences for a range of social, economic, and health outcomes. Importantly, in providing this illustration of how forces at multiple levels of influence—in this case, features of the urban environment—shape long-term health, Block et al. highlight the limitations we face if we do not consider these forces. If we considered health only at one point in time, ignoring its foundational drivers, we would aim to intervene simply on consequences, unlinked to their causes, which would lead us to overly simplistic solutions that will not stand the test of time.

INFLECTING THE TRAJECTORY OF HEALTH

The highlighted article on multilevel perspectives articulates why multilevel and life course perspectives are so important. At core, they help us focus on the causes of population health so that we may intervene effectively, to inflect the trajectory of health for the better. It is also clear that if we do not understand foundational drivers, our scholarship and practice are likely to be moored in present-day, individual-based action, to privilege individual behavioral changes (including medical curative efforts) over efforts that aim to produce health sustainably and prevent disease. The tension between these approaches has been a central topic of discourse in many of our Public Health of Consequence commentaries, in which we have shown our preference for a focus on the latter approach. Our work must be explicitly grounded in multilevel and life course perspectives.