Effectiveness of a school-based health education intervention on tobacco use intention among adolescents: a cluster-randomised controlled trial

BACKGROUND: Adolescence is a critical period for tobacco initiation, and intention to use tobacco strongly predicts uptake. In Nigeria, adolescent tobacco use is a growing concern requiring early prevention. We evaluated a Health Belief Model (HBM)-based tobacco-education intervention on knowledge, harm-perception and intention to use tobacco among in-school adolescents in Ibadan, Nigeria. METHODS: ; the CG participants received a general health lecture. Assessments were conducted at baseline, immediately postintervention and at 6 months. The primary outcome was intention to use tobacco; secondary outcomes included tobacco-related knowledge and harm-perception. Analyses followed intention-to-treat principles. Cluster-adjusted logistic generalised estimating equation models were used to estimate intervention effects on intention. RESULTS: At baseline, intention to use tobacco was identical in both groups (13.6%). At 6-month follow-up, intention declined in the IG (8.9%) but increased in the CG (14.4%). In cluster-adjusted analyses, IG participants had lower odds of reporting intention to use tobacco than CG participants (adjusted OR 0.57, 95% CI 0.35 to 0.94), with no evidence of effect modification by age group. The IG also showed greater improvements in knowledge and harm-perception. CONCLUSIONS: This brief, theory-driven, culturally adapted school-based intervention reduced intention to use tobacco and improved tobacco-related knowledge and harm-perception among adolescents. The findings support the integration of evidence-based tobacco education into adolescent tobacco prevention strategies in low-income and middle-income countries. TRIAL REGISTRATION NUMBER: PACTR202103802475677.