Efficacy of a theory-based abstinence-only intervention over 24 months: a randomized controlled trial with young adolescents.

OBJECTIVE To evaluate the efficacy of an abstinence-only intervention in preventing sexual involvement in young adolescents. DESIGN Randomized controlled trial. SETTING Urban public schools. PARTICIPANTS A total of 662 African American students in grades 6 and 7. INTERVENTIONS An 8-hour abstinence-only intervention targeted reduced sexual intercourse; an 8-hour safer sex-only intervention targeted increased condom use; 8-hour and 12-hour comprehensive interventions targeted sexual intercourse and condom use; and an 8-hour health-promotion control intervention targeted health issues unrelated to sexual behavior. Participants also were randomized to receive or not receive an intervention maintenance program to extend intervention efficacy. OUTCOME MEASURES The primary outcome was self-report of ever having sexual intercourse by the 24-month follow-up. Secondary outcomes were other sexual behaviors. RESULTS The participants' mean age was 12.2 years; 53.5% were girls; and 84.4% were still enrolled at 24 months. Abstinence-only intervention reduced sexual initiation (risk ratio [RR], 0.67; 95% confidence interval [CI], 0.48-0.96). The model-estimated probability of ever having sexual intercourse by the 24-month follow-up was 33.5% in the abstinence-only intervention and 48.5% in the control group. Fewer abstinence-only intervention participants (20.6%) than control participants (29.0%) reported having coitus in the previous 3 months during the follow-up period (RR, 0.94; 95% CI, 0.90-0.99). Abstinence-only intervention did not affect condom use. The 8-hour (RR, 0.96; 95% CI, 0.92-1.00) and 12-hour comprehensive (RR, 0.95; 95% CI, 0.91-0.99) interventions reduced reports of having multiple partners compared with the control group. No other differences between interventions and controls were significant. CONCLUSION Theory-based abstinence-only interventions may have an important role in preventing adolescent sexual involvement. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00640653.