This is the protocol for a review and there is no abstract. The objectives are as follows:
Primary research objective
To review the effects of interventions implemented up to 18 years of age for the primary or secondary prevention of multiple risk behaviours in individuals aged 8-25 years.
In this review, multiple risk behaviours are considered as two or more behaviours, but interventions that address certain combinations of behaviours are excluded to avoid overlap with other reviews. These include those that target just two behaviours including unhealthy diet, low levels of physical activity and/or high levels of sedentary behaviour; and those that target a combination of tobacco use, alcohol consumption and/or drug use (see the types of interventions section).
Secondary research objectives
To explore whether the effects of the intervention differ within and between population subgroups.
To explore whether the effects of the intervention differ by risk behaviour and by outcomes.
To explore the influence of the setting of the intervention in the design, delivery and outcomes of the interventions.
To explore the relationship between the number and/or types of component(s) of an intervention, duration, and effects of the interventions.
To explore whether the impact(s) of interventions differ according to whether behaviours are addressed simultaneously or sequentially and/or whether behaviours are addressed in a particular order.
To explore the association between clustering of particular behaviours and the effects of the interventions.
To explore the cost-effectiveness of interventions.
To identify the implications of the findings of the review for further research, policy and practice.