PURPOSE: Social and economic contextual factors may promote concurrent sexual partnerships, which can accelerate population HIV/STI transmission and are more common among African Americans than U.S. Whites. We investigated the relationship between contextual factors and concurrency. METHODS: We analyzed past-12-month concurrency prevalence in the 2002 National Survey of Family Growth and its contextual database in relation to county sex ratio (among respondent’s racial/ethnic group), percentage in poverty (among respondent’s racial/ethnic group), and violent crime rate. Analyses examined counties with balanced (0.95–1.05 males/female) or low (<0.9) sex ratios. RESULTS: Concurrency prevalence was greater (OR; 95% CI) in counties with low sex ratios (1.67; 1.17, 2.39), more poverty (OR 1.18; 0.98, 1.42 per 10 percentage-point increase), and higher crime rates (OR 1.04; 1.00,1.09 per 1,000 population/year). Notably, 99.5% of Whites and 93.7% of Hispanics, but only 7.85% of Blacks, lived in balanced sex ratio counties; about 5% of Whites, half of Hispanics and three-fourths of Blacks resided in counties with > 20% same-race poverty. CONCLUSIONS: The dramatic Black-White differences in contextual factors in the US and their association with sexual concurrency could contribute to the nation’s profound racial disparities in HIV infection
