Putting Action into Population Health Science: Primary Care Interventions to Address Social Determinants of Health.

Concern about health equity and social determinants of illness (e.g., income inequalities, lack of education, food insecurity) figure prominently in many conceptions of population health. In order to illustrate how population health can actively translate science into action, we consider primary care interventions that promote healthy populations by addressing the social determinants of health. In the examples provided in this article, primary care and population health are linked in a way that reinforces each other, and these innovative interventions may lead to improved health outcomes. Population health science provides a variety of methods and approaches for designing and evaluating interventions that aim to link patients with community resources that can address social determinants of health and improve the quality of their lives. Population health can serve as an important bridge between primary care and the public health sector. Population health science has been defined as "the study of the conditions that shape distributions of health within and across populations, and of the mechanisms through which these conditions manifest as the health of individuals" (Keys, K.M. 2016). According to this perspective, population health science elucidates the mechanisms that produce disease and the discipline of public health then applies that information to promote health in populations. Put another way, population health can be seen as the basic science of public health (Galea, S., et al. 2018). Other conceptions of population health have a direct concern with the translation of science into actions, and view science and action as linked and reinforcing each other (Kindig, D., et al. 2003; Diez Roux, A.V, 2016). For example, Kindig & Stoddart (2003) differentiated population health from public health, health promotion, and social epidemiology and argued that "the field of population health includes health outcomes, patterns of health determinants, and policies and interventions that link these two." The thesis of this commentary is that population health science goes beyond studying the mechanisms that shape distributions within and across populations to include actions that promote health of the entire human population. In support of this thesis, examples are provided from the literature on interventions in primary care that promote healthy populations by addressing the social determinants of health.