A Public Health of Consequence: Review of the April 2016 Issue of AJPH

This month we start coupling this column with an editorial invited to complement the articles about which we are commenting. We intend the invited editorials to cover particular areas of concern around thinking of a public health of consequence, engaging around areas that we observe emerging from articles submitted to AJPH that aspire to inform our scholarship around a public health of consequence. This month’s opinion editorial in the section Public Health of Consequence¹ introduces the notion of population health science as a discipline, arguing that such a discipline draws from a range of existing disciplines—from the social sciences to the natural sciences. The goal of population health science, as suggested in the editorial, would be

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.^1(pXX)

This then sets up the discipline well to be a foundational discipline that aspires to a public health of consequence—the subject of this series of editorials. In particular, Keyes and Galea¹ suggest that some of the principles of such a discipline (informed, as noted in the editorial, by the work of Geoffrey Rose), including that causes of such distributions of health between populations may be distinct from causes of health within populations, and that ubiquitous causes can exert a powerful impact on disease incidence but remain unseen without examining cross-population variation, represent foundational directions for a public health of consequence.

Several of the articles in this issue of AJPH well illustrate these points. The article by Hatch et al.² explores an issue that has been at the forefront of the health debate in this country over the past seven years and has been a constantly highlighted issue in this column—insurance coverage. Hatch et al. illustrate how those individuals who maintained insurance coverage through Oregon’s Medicaid expansion had long-term utilization of community health centers compared with those who had discontinuous coverage who had no comparable long-term utilization. Health insurance coverage is a classic example of a ubiquitous cause that can have a powerful impact on population health. In many ways, health insurance aims to provide a “health floor,” an opportunity for those insured to have access to clinical care through the health system. As has been amply argued in previous articles, clinical care is just one, relatively small, piece of the production of population health.³ It is, however, an important piece and one with resonance for all individuals who experience immediate health threats and benefit therefore from access to health system resources. Therefore, the provision of health insurance ubiquitously levels the health playing field, providing an opportunity for all individuals to receive clinical care when needed, and for the overall improvement of population health. Their elegantly simple visual presentation of the effect that insurance has on primary care utilization over time by group, presented in their Figure 1,^2(pXX) is more powerful than any table of regression coefficients. This simple demonstration of the efficacy of insurance coverage toward use of services in the article by Hatch et al. is even more sobering when we remember that 22 states have not accepted Medicaid expansion as part of the Affordable Care Act, leaving 4.3 million Americans unnecessarily uninsured.

This point is further underlined in the article by Nuñez et al.,⁴ who demonstrate the effectiveness of universal health coverage programs Plan Nacer and Programa Sumar in Argentina. This article impressively demonstrates that the prevalence of stunting and underweight decreased 45% and 38%, respectively, among children enrolled in the programs. Childhood stunting and underweight have long-arc implications for children throughout the life course. The demonstration that health insurance coverage is associated with a life course determinant that can influence trajectories of health and well-being over time is an elegant demonstration of the importance of high prevalence, ubiquitous determinants of health—like in this case, insurance coverage—and the role that they play in improving the health of populations.

The importance of upstream determinants that are ubiquitous and have widespread effects on populations is also demonstrated in the article by Jin et al.,⁵ who show that in cities in California and Massachusetts with tobacco-free pharmacy laws there is a 40% to 200% reduction in tobacco retailer density over time, suggesting a positive diffusion, perhaps the generation of a social consensus around tobacco leading to fewer tobacco retailers. The association between retailer density and tobacco consumption is well established,⁶ suggesting that the implementation of tobacco-free pharmacy laws can have positive health consequences well beyond the direct and intended influence of such efforts that change the underlying structural environment.

We comment, in conclusion, on one more article in this vein that sounds, however, perhaps a cautionary note. Esser et al. studied alcohol interventions sponsored by the alcohol industry that aim to reduce drunk driving.⁷ Conducting a systematic analysis of the contents of 266 initiatives, they found that only a tiny fraction of these interventions were based on documented efficacy, suggesting that a substantial proportion of these interventions may well be futile. An engaged public health that aims to improve the conditions that create the health of populations must, by definition, engage all sectors—including public and private partners—to achieve its goals. However, the article by Esser et al. is a good reminder that engaging in such partnerships must not jeopardize foundational focus on implementing effective interventions that indeed achieve their stated goal of improving the health of populations.