Chlamydia and gonorrhea incidence and residential segregation: US spatiotemporal patterns (2013-2021).

OBJECTIVE: Investigate the association between residential segregation and the incidence of chlamydia and gonorrhea from 2013 to 2021 at the county level in contiguous U.S. states. METHODS: National-level secondary US data from 2013 to 2021 from the Centers for Diseases Control and Prevention Sexually Transmitted Infection surveillance dataset, American Community Survey, and Racial Segregation Index were analyzed using the Generalized Estimating Equation, and spatial regression. Analysis was divided into two periods (2013-2019; 2020-2021) to account for COVID-19 disruptions. Residential segregation was measured by dissimilarity index categorized into reference (< 0.25), moderate (0.26-0.50), high (0.51-0.75), and extreme (> 0.75) levels. Primary outcome measures were chlamydia and gonorrhea incidence rates. Residential segregation was the key independent variable with other social determinants of health covariates. 3,211 counties within the contiguous United States were included within this study. Counties with missing data, and not within the contiguous United States were excluded. RESULTS: For chlamydia, from 2013 to 2019, segregation coefficients (i.e.,13.77 and 15.84 for moderate and high segregation) indicated that greater residential segregation was associated with higher chlamydia incidence rates (P < 0.0001). From 2020 to 2021, these coefficients increased (from 13 to 15 to 28.25 and 34.16), suggesting growing segregation-driven disparities. Gonorrhea followed a similar trend, with the coefficients increasing from 0.47 to 0.55 (P < 0.001) to 1.53 and 1.62 (P < 0.05), respectively. Spatial variation in the association between segregation and chlamydia incidence remained consistent, with more pronounced associations in the Southeastern, Midwest, and Western regions. Spatial variation in the association between segregation and gonorrhea incidence were more pronounced in the South and parts of the Midwest, with weaker associations in some Northern and Western regions. CONCLUSIONS: Residential segregation remained associated with chlamydia and gonorrhea transmission. The spatial patterns varied over time for both diseases. Further research should extend post-COVID-19 analysis to assess evolving relationships between residential segregation and STI incidence across U.S. regions. KEY POINTS: What is already known on this topic: Chlamydia and gonorrhea in 2023 were the most reported sexually transmitted infections in the United States, disproportionately affecting Black Americans. WHAT THIS STUDY ADDS: This study found that residential segregation was associated with race-specific differences in chlamydia and gonorrhea transmission, especially during the COVID-19 pandemic.How this study might affect research, practice or policy: Study findings suggest that interventions aiming to reduce chlamydia and gonorrhea incidence rates in the United States should also include intervention activities that address adversities associated with residential segregation.