Loneliness is correlated with cancer mortality in US counties: an ecological analysis.

BACKGROUND: Loneliness is a social determinant of health linked to downstream health consequences, but little to no research has examined the association between loneliness and cancer mortality at the community level. This study evaluates whether loneliness functions as a population health indicator associated with variation in cancer mortality rates. METHODS: We analyzed county age-adjusted cancer mortality rate data from the National Cancer Institute (5-year estimates, 2018-2022) merged with 2022 County Health Rankings data on sociodemographic and health behavior covariates (N = 1303). Loneliness was measured as the percentage of adults reporting subjective feelings of loneliness; the outcome was age-adjusted all-site cancer mortality per 100,000 population. General linear models assessed associations between loneliness and all-site cancer mortality, adjusting for sociodemographics, health behaviors, and rurality. RESULTS: In unadjusted analyses, county-level loneliness was positively associated with cancer mortality rates (β = 1.88, p < 0.001). Fully adjusted models showed loneliness's association with cancer mortality rates remained significant (β = 0.88, p < 0.001). Sociodemographic and health covariates were differentially associated with cancer mortality rates. DISCUSSION AND CONCLUSIONS: Higher-loneliness counties exhibit higher cancer mortality rates, suggesting that monitoring county-level social indicators may inform public health surveillance and guide future research on social determinants of cancer outcomes.