Objective: To determine whether an interactive curriculum that integrates dating violence prevention with lessons on healthy relationships, sexual health, and substance use reduces physical dating violence (PDV).
Design: Cluster randomized trial with 2.5-year follow-up; prespecified subgroup analyses by sex.
Setting: Grade 9 health classes.
Participants: A total of 1722 students aged 14-15 from 20 public schools (52.8% girls). Intervention A 21-lesson curriculum delivered during 28 hours by teachers with additional training in the dynamics of dating violence and healthy relationships. Dating violence prevention was integrated with core lessons about healthy relationships, sexual health, and substance use prevention using interactive exercises. Relationship skills to promote safer decision making with peers and dating partners were emphasized. Control schools targeted similar objectives without training or materials.
Main outcome measures: The primary outcome at 2.5 years was self-reported PDV during the previous year. Secondary outcomes were physical peer violence, substance use, and condom use. Analysis was by intention-to-treat.
Results: The PDV was greater in control vs intervention students (9.8% vs 7.4%; adjusted odds ratio, 2.42; 95% confidence interval, 1.00-6.02; P = .05). A significant group x sex interaction effect indicated that the intervention effect was greater in boys (PDV: 7.1% in controls vs 2.7% in intervention students) than in girls (12.1% vs 11.9%). Main effects for secondary outcomes were not statistically significant; however, sex x group analyses showed a significant difference in condom use in sexually active boys who received the intervention (114 of 168; 67.9%) vs controls (65 of 111 [58.6%]) (P < .01). The cost of training and materials averaged CA$16 per student.
Conclusion: The teaching of youths about healthy relationships as part of their required health curriculum reduced PDV and increased condom use 2.5 years later at a low per-student cost.