Small numbers, big impact: making a utilitarian case for the contribution of inclusion health to population health in England.

Inclusion health groups make up a small proportion of the general population, so despite the extreme social exclusion and poor health outcomes that these groups experience, they are often overlooked in public health investment and policy development. In this paper, we demonstrate that a utilitarian argument can be made for investment in better support for inclusion health groups despite their small size. That is, by preventing social exclusion, there is the potential for large aggregate health benefits to the whole population. We illustrate this by reframing existing published mortality estimates into population attributable fractions to show that 12% of all-cause premature deaths (95% CI 10.03% to 14.29%) are attributable to the circumstances of people who experience homelessness, use drugs and/or have been in prison. We also show that a large proportion of cause-specific premature deaths in the general population can be attributed to specific inclusion health groups, such as 43% of deaths due to viral hepatitis (95% CI 30.35% to 56.61%) and nearly 4000 deaths due to cancer (3844, 95% CI 3438 to 4285) between 2013 and 2021 attributed to individuals who use illicit opioids. Considering the complexity of the inclusion health policy context and the sparseness of evidence, we discuss how a shift in policy framing from 'inclusion health vs the rest of the population' to 'the impact of social exclusion on broader population health' makes a better case for increased policy attention and investment in inclusion health. We discuss the strengths and limitations of this approach and how it can be applied to public health policy, resource prioritisation and future research.