Geographic Factors Associated with Racial/Ethnic Assortative Mixing in the United States, 2015-2019

Background: During increasing STIs, we examined whether two geographic factors were associated with racial/ethnic assortative mixing (having a partner with same race/ethnicity) which has been associated with STIs. Methods: We used data from a U.S. household-based survey of 15–49-year-olds (N= 21,441). 2015-2019 response rates were 65.9% (women) and 62.4% (men). We included two measures of geography: residing in a metropolitan statistical area (MSA) and U.S. nativity (measure of migration), and other covariates. Our analytic sample (n=3,678) consisted of 15–44-year-olds who were separated, unmarried, or not cohabiting with an opposite-sex partner and sexually active (past 12 months). Analyses accounted for the complex survey design. Wald F tests and logistic regression were used. Results: In adjusted analyses, U.S. native Hispanic women (aPR=0.76; 0.62-0.92) were significantly less likely to report assortative mixing than non-U.S. native Hispanic women. Among males, U.S. native Hispanic men (aPR=0.81; 0.71-0.82) were significantly less likely to report assortative mixing than non-U.S. native Hispanic men. Non-Hispanic White men living in the principal city of a MSA (aPR=0.88; 0.82-0.94) were less likely to report assortative mixing than non-Hispanic White men living outside of a MSA. Finally, non-Hispanic black men who lived in a MSA but not a principal city (aPR=0.76; 0.5-0.99) were significantly less likely to report assortative mixing than those living outside of a MSA. Conclusions: Racial/ethnic assortative mixing varied by sex, race/ethnicity, residence in a MSA and U.S. nativity. Further exploration of geographic factors could aid in developing interventions to reduce STI differences through tailored interventions.