Effectiveness of school-based intervention in smoking reduction: A systematic review and synthesis without meta-analyses (SwiM)

INTRODUCTION Smoking among adolescents is a major public health problem.Several reviews have examined the effectiveness of school-based smoking trials in preventing smoking, but few have examined a reduction in smoking among students.This review synthesizes evidence on schoolbased smoking interventions to determine their effectiveness in reducing smoking among secondary school students.METHODS This review was guided by the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) and Synthesis Without Meta-analyses (SWiM) extension statement.Electronic databases search was carried out systematically from 2000 until 31 December 2020, with updates until 15 June 2025.Studies were included if they reported school-based intervention studies among secondary students and reported smoking reduction as the outcome.The Cochrane Risk of Bias Tool-2 was used to assess the study quality.Narrative synthesis was used to synthesize