Comparison of Chlamydia trachomatis Seroprevalence and Risk Factors for Infection Among Women by Gender/Sex of Sex Partner, United States, 2013-2016.

Abstract

Objectives: Women who report sex with women are thought to have a lower risk of Chlamydia trachomatis (CT) infection than women who report sex with men only (WSM-only), but comparisons of lifetime burden are limited.

Methods: Among 1418 sexually experienced women aged 18 to 39 years participating in the National Health and Nutrition Examination Survey (2013-2016), we estimated weighted CT seroprevalence and Wald-based 95% confidence intervals (CIs) in women who reported ever having sex with a woman (all reported having sex with men also) (WSWM) compared with WSM-only. We defined seropositivity as detection of Pgp3 antibodies and used stratified Poisson regression with robust standard errors to estimate prevalence ratios (PRs).

Results: More than half (58.3%) were White non-Hispanic; 16.2% were WSWM. Women who had sex with women and men were somewhat younger (mean, 27.8 vs. 29.0 years; P = 0.07), were younger at sexual debut (mean, 15.6 vs. 17.5 years; P < 0.001), and had more lifetime male sexual partners (mean, 15.9 vs. 6.4; P < 0.001) than WSM-only. Weighted CT seroprevalence was 38.9% (95% CI, 30.4%-47.4%) in WSWM and 28.6% (95% CI, 24.4%-32.9%) in WSM-only. Correlates of higher CT seroprevalence in both groups were Black non-Hispanic race/ethnicity, Hispanic ethnicity, and CT infection in the prior year. Having ≥5 lifetime male partners compared with 1 to 2 partners was associated with higher seroprevalence among WSWM (PR, 4.5; 95% CI, 1.77-11.44) and WSM-only (PR, 2.7; 95% CI, 1.87-3.69). Among WSWM, bisexual identity was associated with lower seroprevalence. Among WSM-only, low income and younger age at sexual debut were associated with higher seroprevalence.

Conclusion: Lifetime CT burden was higher in WSWM than WSM-only. Number of lifetime male partners was the strongest predictor of seropositivity for WSWM.