Sex partner concurrency - Measurement, prevalence, and correlates among urban 18-39-year-olds

Background: Sex partner concurrency probably accelerates the spread of sexually transmitted disease (STD) and HIV, yet few data exist on population prevalence or correlates. Goal: The goal of the study was to compare definitions and estimate the frequency of concurrent partnerships and to identify individual and partnership correlates of concurrency. Study Design: A random-digit-dialing survey (n = 637) was performed to collect demographic information, sexual history and history of STD, and partnership characteristics. Results: Men reported concurrency more frequently than women. For men, lifetime partners (odds ratio [OR], 1.15 per partner; 95% CI, 1.07-1.23), a night in jail (OR, 1.99; 95% CI, 1.03-3.82), and same sex partners (OR, 1.88; 95% CI, 0.92-3.84) were associated with concurrency. Important factors for women were first coitus before age 16 (OR, 2.90; 95% CI, 1.38-6.10), lifetime partners (OR, 1.09 per partner; 95% CI, 1.01-1.16), and STD diagnoses during relationship (OR, 3.53; 95% CI, 1.55-8.05). Partnership characteristics associated with concurrency included lifetime partners (OR, 1.09; 95% CI, 1.05-1.14), race discordance (OR, 1.72; 95% CI, 1.14-2.59), married/living together (OR, 0.60; 95% CI, 0.36-0.98), night in jail (OR, 2.04; 95% CI, 1.32-3.17), partnership duration of >6 months (OR, 2.43; 95% CI, 1.41-4.19), and STD diagnoses during relationship (OR, 2.68; 95% CI, 1.42-5.07). Conclusions: Concurrency was independently associated with individual STD risk. Sex differences may reflect true behavioral differences or differential reporting.