Inclusion health: addressing the causes of the causes

The social gradient in health describes a graded association between an individual’s position on the social hierarchy and health: the lower the socioeconomic position of an individual, the worse their health. The fact that the social gradient extends from the highest echelons of society to the lowest suggests that everyone is affected to a greater or lesser extent by the social determinants of health. One component of social cohesion is making common cause between people at various points on the social ladder. However, people at the extremes can appear to be on a different scale to the rest of society. F Scott Fitzgerald famously began his story The Rich Boy, “Let me tell you about the very rich. They are different from you and me”. In societies with substantial inequality, the considerable gap between the top 0·1% of income earners and the rest of society threatens social cohesion. Different, too, are socially excluded populations: the homeless, people with substance use disorders, sex workers, and prisoners. These individuals can seem to be off the scale of the social hierarchy completely, which represents a further challenge to social cohesion. For example, in the first of two papers on inclusion health in The Lancet, Robert Aldridge and colleagues found that socially excluded populations have a mortality rate that is nearly eight times higher than the average for men, and nearly 12 times higher for women. By contrast, individuals (aged 15–64 years) in the most deprived areas of England and Wales have a mortality rate that is 2·8 times higher in men and 2·1 times higher in women than in individuals in the least deprived areas. To adapt Jeremy Bentham’s turn of phrase, social exclusion is deprivation upon stilts. To put it less colourfully, the causes of excess morbidity and mortality in socially excluded populations (ie, the social determinants of health) are not so much different from the causes of health inequalities more generally but differ in their degree. Multiple intersecting causes and multiple forms of morbidity characterise social exclusion. The result is people with little hope or prospects and considerably shortened lives. The challenge is to bring socially excluded populations in from the cold—literally and metaphorically—and to provide them with the opportunity to be part of a diverse and flourishing society. The concerned practitioner might despair at achieving such social inclusion. The second of the two papers on inclusion health in The Lancet,by Serena Luchenski and colleagues, provides evidence to banish despair. The authors report that intervention is possible and can make a difference to the lives of the four excluded groups included in their Review: homeless individuals, prisoners, sex workers, and people with substance use disorders. These four populations, of course, overlap—eg, substance use disorder is common in the other three socially excluded groups. The methods used in both papers are of high quality. But therein lies a problem. As identified by Luchenski and coworkers, the effect of basing their work on systematic reviews is a focus on proximate interventions on individuals—eg, the Review includes many papers on pharmacological treatment of substance use disorder. These downstream interventions have been covered, for the most part, in the scientific literature. There has been much less focus on structural interventions. If one went purely by the numbers of papers published, one would put effort into pharmacological treatment and would ignore housing; emphasise case management and ignore poverty. Much of the literature included in Luchenski and coworkers’ Review was from populations with substance use disorders, with few publications about homeless people and prisoners, and almost no studies on sex workers. For individuals committed to evidence-based policies, this poses a dilemma: efforts that promote social inclusion have to be encouraged, but the fact that sex workers have not been included in systematic reviews, Published Online November 11, 2017 http://dx.doi.org/10.1016/ S0140-6736(17)32848-9