Context matters: Geographic and age differences explain high heterogeneity in social isolation

• Several health and social factors are associated with social isolation. • Geographic and age differences explain significant social isolation heterogeneity. • We observed higher isolation in regions with low incomes or high population densities. • Members of marginalized racial groups had elevated odds ratios for isolation. • Interventions combatting isolation must be intersectional and malleable to local needs. Many studies have examined social and health-related factors associated with social isolation. However, the degree to which contextual factors and social determinants such as geography, age, and race compare against health-related factors in explaining heterogeneity in population-level social isolation is not well understood. To address this gap, we analyzed data from the largest-known dataset on social isolation ( n = 73,737) from adults in central Minnesota. Linear mixed effect modeling showed that ZIP code and age significantly explain variance in isolation levels among respondents, even after controlling for individual-level factors like health. Regions with lower median incomes or higher population densities were associated with increased levels of isolation. Disparities in levels of social isolation by race and sexual orientation were also present. We conclude that social contexts may modulate the way individuals interact with others and thus modulate the prevalence of social isolation. Therefore, interventions supporting social connections must be inclusive, intersectional, and malleable to the unique communities they are built for.