The association between social capital and cancer screening rates in the United States.

e22550 Background: Cancer screening remains a cornerstone of cancer prevention, yet substantial geographic variation persists in screening uptake across the United States (U.S.). While prior studies have examined social capital and cancer screening primarily at the individual and neighborhood levels, data examining these associations at the county level remain limited. We assessed the association between county-level social capital and breast, cervical, and colorectal cancer screening rates across all 50 U.S states and Washington, DC. Methods: This was an ecological study using retrospective data obtained from the CDC’s PLACES 2023 dataset which includes county-level breast, cervical, and colorectal screening rates consistent with USPTF recommendations. County-level social capital was measured using the standardized Social Capital Index (SCI) developed by the U.S. Congress’ Social Capital Project, a composite measure encompassing family stability, trust and confidence in institutions, community cohesion, social network characteristics, and civic engagement. Counties were categorized as having low (less than −1 SD), average (−1 to +1 SD), or high (greater than +1 SD) social capital relative to the mean across all counties. Associations between county-level social capital and cancer screening rates were assessed using multilevel negative binomial regression models with robust standard errors. Results: Among 2,991 counties analyzed, 65% had average, 15% had low, and 20% had high social capital. Cervical cancer screening rates were significantly higher in counties with average (RR 1.010; 95% CI, 1.008–1.013) and high (RR 1.019; 95% CI, 1.015–1.022) social capital compared with counties with low social capital. Similarly, colorectal cancer screening rates were higher in counties with average (RR 1.021; 95% CI, 1.016–1.025) and high (RR 1.035; 95% CI, 1.029–1.041) social capital compared with low social capital counties. In contrast, breast cancer screening rates were modestly lower in counties with average social capital (RR 0.993; 95% CI, 0.989–0.997), compared with counties with low social capital, while the association with high social capital was inconclusive (RR 1.000; 95% CI, 0.994–1.005). Conclusions: Higher county-level social capital was associated with increased cervical and colorectal cancer screening rates, whereas associations with breast cancer screening were weaker and inconsistent. These findings suggest that structural and social determinants reflected in social capital such as family stability, community cohesion, civic engagement, and trust in institutions, may influence population-level uptake of preventive health services. Public health strategies that strengthen social capital may complement health system-based efforts to improve cancer screening coverage.