Racial differences in associations between adolescent substance use and sexually transmitted infection (STI) and sexual risk behavior in adulthood

Background: Substance use is strongly and consistently correlated with sexually transmitted infection (STI) risk, yet few studies have examined the longitudinal relationship. Estimation of the longitudinal associations between adolescent substance use and adult STI risk will enable assessment of whether reductions in adolescent drug use may contribute to reductions in adult risk behavior and infection. Methods: Wave I (1995: adolescence) and Wave III (2001-2002: young adulthood) of the National Longitudinal Study of Adolescent Health (N=13,123) were used to examine racial (black vs. white) differences in longitudinal associations between alcohol, marijuana, and cocaine use in adolescence (in the year prior to Wave I) and adult STI risk at Wave III, including multiple sex partnerships in the year prior to Wave III and biologically-confirmed chlamydia, gonorrhea, or trichomoniasis infection. Results: The most commonly-used drug was alcohol, followed by marijuana and cocaine. Among all groups, adolescent alcohol and marijuana use were significant predictors of multiple partnerships. Getting drunk in adolescence was associated with increased STI risk among whites (men: RR: 1.75, 95% CI: 1.03-2.97; RR: 1.68, 95% CI: 1.01-2.78), but not blacks. Among white women, adolescent cocaine use was associated with increased risk of multiple partnerships and STI (multiple partnerships: RR: 1.37, 95% CI: 1.04-1.80; STI: RR: 2.80, 95% CI: 1.36-5.76). Cocaine use was not associated with multiple partnerships among black men or women, but was strongly associated with STI among men (RR: 2.88, 95% CI: 1.18-7.05). Conclusions: Adolescent substance use may represent a modifiable STI risk factor among both black and white youth.