Background Increasingly constrained school timetables mean that there is often little space for specifically timetabled health education lessons. Interventions that integrate health education into academic lessons may prove more appealing to schools, and may be a promising means of addressing outcomes such as violence and substance use while also promoting academic attainment. This evidence has not yet been systematically reviewed. We synthesised evidence for these interventions’ effectiveness and analysed their components.

Methods We searched 19 bibliographic databases and 32 websites. References were extracted from the reference lists of included studies and authors were contacted.We included reports with no restrictions on language or date. References were screened on title/abstract and those passing this screening were then screened on full report. Data extraction and appraisal were informed by the Cochrane risk of bias tool. Outcome evaluations were synthesised by key stage (KS) using multilevel meta-analysis where possible; otherwise, evidence was narratively synthesised. Components were analysed inductively. This study is registered as PROSPERO 2015:CRD42015026464.

Results 78 451 unique references were identified, of which 35 (13 studies) evaluated outcomes. Quality of evidence was highly variable, and often related to whether meta-analysis was possible. The strongest evidence for the effectiveness of interventions integrating academic and health education was found in the reduction of substance use in KS2 and KS3, and a meta-analysis for the effectiveness of these interventions in reducing violence victimisation in KS2 did not find an effect. We described intervention components in terms of a) the number of domains (school, classroom, family) targeted, b) the planned duration of the intervention, c) how integration was specified (using literature, teaching study skills, supporting teachers to integrate in their own classrooms).

Discussion There is under-theorisation and understanding of characteristics affecting implementation of integrated academic and health curricula as well as appreciation of how academic attainment and reduced risk-taking may be linked. However, available data suggest that multi-level interventions that aim to erode boundaries—or rather, strengthen pro-social relationships—between academic and health curricula, teachers and students, classrooms and schools and schools and families are likely to have the greatest impact on reducing risk-taking and improving academic outcomes. These programmes may be effective in reducing substance use but do not appear to reduce outcomes related to violence.