Effect of Health Promotion Intervention on Knowledge of Non-Communicable Diseases among In-School and Out-of-School Adolescents in Rivers State, Nigeria: A Comparative Quasi-Experimental Study

Non-communicable diseases (NCDs) knowledge gaps among Nigerian adolescents threaten health. This study compares in-school and out-of-school adolescents’ NCD knowledge in Rivers State, South-South Nigeria. A comparative quasi-experimental study design was conducted among 372 in-school and out-of-school adolescents in Rivers State, South-South Nigeria using multi-stage sampling technique. Knowledge of NCDs was assessed using a validated interviewer-administered questionnaire at baseline and six months’ post health education intervention. Knowledge scores were categorized as poor (0–49%), moderate (50–69%), and good (70–100%). Data were analyzed using IBM SPSS version 27. Numerical variables were summarized as means and standard deviations, while categorical data was summarized using proportions and percentages. Knowledge scores were compared between groups using Chi-square, Fisher’s exact or independent t-tests. Within-group pre–post changes were assessed with the McNemar test. Logistic regression identified predictors of NCD knowledge. Statistical significance was set at p