Gender-Affirming Care and Health Outcomes Among Transgender and Gender Expansive Youth: Research Advances and Future Priorities.

Health inequities are widely recognised as avoidable and unjust differences in health arising from how society and the economy are organised (; ). Despite calls to investigate these vertical political and economic determinants of health, (; ; ), empirical research often remains focused on horizontal analyses of people, places, and the relationships between them. Vertical approaches to researching health inequalities focus on the broader systemic and structural determinants of health such as the role of national and international political economies, government policies, and power relations that shape health outcomes across populations. Whereas horizontal approaches concentrate on the more immediate, localised, and individual-level factors which influence health such as people’s ability to access services, their neighbourhood environments, and health behaviours (). This vertical-horizontal framing is developed following who advocate for ‘scaling-up’ analyses to account for political and economic drivers of health, situating inequalities within the broader structures of the political economy. While previous literature on lay perspectives on health inequalities has described horizontal factors such as individual health behaviours, access to services, jobs, and housing (; ; ) there is emerging evidence demonstrating more complex and nuanced understandings of the inter-play between the vertical and the horizontal (; ; ). This shift is welcome as despite decades of research and policy recommendations targeting the horizontal conditions in which people live and work, health inequalities have widened, and life expectancy has declined (; ). This suggests that horizontal approaches fail to understand or address the root causes, namely inequalities in income, wealth, and power (; ). By maintaining a horizontal analytic lens, research overlooks how vertical processes create and sustain health inequalities (; ; ; ). This, in turn, obfuscates the development of policies capable of reducing inequalities and instead favours temporary mitigation strategies (; ). Indeed, frameworks such as the social and commercial determinants of health have drawn attention to how social conditions and corporate practices shape population health. However, these are often applied in reductive or siloed ways that obscure the structural forces underpinning these exposures (; ). In the UK, and other high-income countries, the economy facilities resource flows from poorer to wealthier places, limiting the effectiveness of policies aimed at improving conditions for disadvantaged places. Without addressing these economic flows such policies may yield only moderate or temporary benefits (). This vertical, relational perspective which highlights how societal structures sustain health inequalities is largely absent from empirical research. Some scholars, however, are beginning to reveal the mechanisms by which resources are extracted from disadvantaged groups. , for example, exposes a profitable ‘poverty industry’ in the United States, where private firms and underfunded state governments exploit federal aid intended for vulnerable populations. This work demonstrates how poor families, abused children, the elderly, and disabled individuals are used as a source of revenue ().