social conditions for health, particularly amongst the most vulnerable populations. The commission delivered its final report to the WHO in 2008 (WHO Commission on the Social Determinants of Health 2008).
As defined by the WHO Commission, the social determinants of health are “the conditions in which people are born, grow, live, work, and age” (WHO Commission on the Social Determinants of Health 2008). These social determinants extend well beyond the confines of the health care system and include aspects of our neighborhood and workplace environments (e.g. the food, built, and social environments) and the social and economic policies (e.g. tax policies) that govern the regions in which we live. It is these “upstream” nonmedical social determinants that are increasingly understood as the root causes of population health inequalities, even within rich nations (Marmot and Bell 2009; Woolf and Braveman 2011). Such social determinants offer a critical lens to explain why the average life expectancy in America has lagged well behind other nations, despite the fact that the United States remains one of the richest nations in the world and spends more on a per‐capita basis on health care than all other developed nations globally (Marmot and Bell 2009). Identifying what impacts various social determinants have on population health is now the central focus of the growing public health field known as social epidemiology.
The WHO Commission on the Social Determinants of Health developed a conceptual framework of the social determinants of health (Solar and Irwin 2007; WHO Commission on the Social Determinants of Health 2008). Figure 1.2 shows an adaptation of this conceptual framework. As illustrated in this figure, the social determinants of health are composed of the material living and working conditions and social environmental conditions in which people are born, live, work, and age, along with the structural drivers of these conditions. These structural drivers include individual‐ and area‐level socioeconomic status (SES), race/ethnicity, residential segregation, gender, social capital/cohesion, and the macroeconomic and macrosocial contexts, e.g. macroeconomic and social policies including labor market regulations (Muntaner et al. 2012), political factors including governance and political rights (Chung and Muntaner 2006; Bezo et al. 2012), and cultural factors. Examples of macroeconomic determinants include the gross domestic product (GDP) per capita and income inequality—the gap between the rich and the poor within societies.
Figure 1.2 A social determinants of health conceptual framework.
Source: Adapted from Kim and Saada (2013) and Solar and Irwin (2007).
The broader macroeconomic and social context generates social stratification, that is, the sorting of people into dominant and subordinate SES, racial/ethnic, and gender groups (Figure 1.2). Through social stratification and differential exposures of individuals to levels of material factors/social resources, social determinants such as individual/area‐level SES, race/ethnicity, and social capital shape individual‐level intermediary determinants, including behavioral factors (e.g. maternal smoking), biological factors, and psychosocial factors (e.g. social support), which in turn produce differential risks of, and inequities in, health outcomes (Figure 1.2). Access to health care and the quality of health care are also determinants of these outcomes, yet health care factors are believed to play lesser roles compared to societal factors (Figure 1.2). This is supported by cross‐national evidence on health care spending and life expectancy. Moreover, even in societies with a national health system in place (e.g. Canada and the United Kingdom), socioeconomic disparities and gradients in health are salient and well established.
1.4 The 3 P's (people, places, and policies) Population Health Triad
Implicit in this conceptualization of the social determinants of health is that more upstream population characteristics, places, and policies matter to population health. Jointly, we can refer to these three factors that are pivotal to population health as the “3 P's” (people, places, and policies) Population Health Triad (Figure 1.3). The classic Host–Agent–Environment epidemiologic triad posits that a susceptible host, an external agent, and an environment are needed to produce disease. Similarly, both places and policies interact with populations to manifest disease. For example, neighborhoods where we live can influence our health through physical and material characteristics such as air quality, access to nutritious foods and opportunities for leisure and exercise, health services, and education/schools and employment opportunities (Braveman et al. 2011). Policies in nonhealth sectors (e.g. transportation, education, and housing) can also intersect with and shape health. Social policies such as those that affect levels of welfare spending and tax policies that determine the rich–poor gap have plausible linkages to the social environment, health behaviors, and individual health and disease endpoints. Reciprocal interactions are also possible, with populations being able to shape both policies and places, such as by mobilizing together through social capital (e.g. political activism) to effect change (Figure 1.2).
Figure 1.3 The 3 P's (people, places, and policies) Population Health Triad.
To help address the social determinants of health at a government level, in 2010, the WHO and the Government of South Australia (2010) developed the HiAP approach through the Adelaide Statement on HiAP. In this comprehensive population health strategy, health considerations in policymaking permeate and encompass multiple public sectors that may influence health, such as transportation, agriculture, housing and urban development, and education (Figure 1.4). The HiAP approach was founded on the notion that many social determinants of health are outside the purview of public health agencies. The roots of this radical approach can be traced back to the seminal ideas put forth in the Alma Ata Declaration on Primary Health Care (1978) and the Ottawa Charter for Health Promotion (1986). The HiAP approach became reinforced in the 2011 Rio Political Declaration on Social Determinants of Health (World Health Organization 2016a).
Figure 1.4 Examples of multiple public sectors collectively adopting a Health in All Policies (HiAP) approach.
The HiAP approach has been increasingly adopted in jurisdictions around the world. For example, the Department of Housing and Urban Development (HUD) in the United States has embraced a HiAP approach and is collaborating with the U.S. Department of Health and Human Services (HHS) to ensure the integration of the elderly and disabled into the community via housing and human service agencies to enable them to live as long and as healthily as possible (Bostic et al. 2012). HUD further encourages applicants to regional planning and neighborhood initiative grants to incorporate health metrics into their baseline assessments of neighborhoods and asks them to indicate how they will support regional planning efforts that consider public health impacts (Bostic et al. 2012). Moreover, to attain objectives on the social determinants of health, the HiAP approach has been encouraged by Healthy People 2020 (2010), the U.S. Centers for Disease Control and Prevention initiative that establishes national goals and objectives for
