Background: Understanding how national policy environments shape population health is central to advancing equitable health policy. While prior research suggests that social spending improves health outcomes, particularly in OECD countries, less is known about how these policy environments relate to population health across the life course and across socioeconomic groups in a broader global context. This study provides preliminary cross-national evidence linking national social spending to population health while examining socioeconomic and age-related patterns.

Methods: We utilized data from the 2023 Gallup World Poll (N = 141,126 individuals across 128 countries). Health was measured using the Personal Health Index (α = .77). Country-level social spending (% of GDP) was linked to individual survey responses. We used weighted regression and multilevel models to examine associations between national spending contexts, population health, socioeconomic position, and age.

Results: Substantial cross-national variation in health was observed, with country-level mean health averaging 67.4 (SD = 9.4; range = 37.9-91.2). A strong income gradient was evident: mean health increased from 60.7 in the lowest income quintile to 73.4 in the highest. Higher national social spending was associated with better population health (β = 0.30, p < .001). Health also declined significantly with age (β = -0.56 per year). Multilevel analyses indicate that social spending moderates age-related health decline: each additional unit of spending was associated with an estimated 2.7% reduction in the rate of age-related health decline.

Discussion: These preliminary findings suggest that national spending environments may influence both average population health and age-related health trajectories. Ongoing analyses will incorporate additional social policy indicators and institutional factors to better understand how policy environments shape cross-national health disparities across the life course.