Thirty-seven RCTs (n=52,695) were included in the review.
Smoking cessation (13 studies).
Stage-based versus non stage-based interventions (8 studies): there was no significant difference between groups in behavioural change outcomes for 5 studies; in one study all stage-based interventions outperformed the non stage-based intervention; 2 studies found mixed effects.
Stage-based intervention versus usual care control group (6 studies): there were no between-group differences for 3 studies at final follow-up; the other 3 studies found significant differences favouring the intervention group for scores on quit rates.
Promotion of physical activity (7 studies).
Stage-based versus non stage-based and usual care interventions (2 studies): one study found no significant difference between groups for the outcome, while the second study was unclear as to whether there was any difference in effectiveness scores.
Stage-based intervention versus usual care or information-only control group (7 studies): there was no significant difference between groups in behavioural change outcomes for 3 studies; 3 studies found significant differences favouring the stage-based intervention, though the effect only lasted for a maximum of 12 weeks; one study did not report data on behaviour change.
Dietary change (5 studies).
Stage-based versus non stage-based interventions (3 studies): there was a significant difference between groups favouring the stage-based intervention in one study; there were no significant differences between groups in another study; and mixed results were found in the third study.
Stage-based intervention versus usual care control group (3 studies): there was a significant difference between groups favouring the stage-based intervention in two of the studies, one of which found a significant difference for some outcomes and the other for all outcomes; there was no significant difference between groups in the third study.
Multiple lifestyle changes (smoking, dietary intake, physical activity and substance use (6 studies).
There was a significant difference in favour of the stage-based intervention compared with a usual care group in one study. There were no significant differences between groups for any outcomes measured in 3 studies (in two of these studies the comparison was with a no intervention group and in one it was with usual care). There were mixed effects in the remaining 2 studies (in one study the comparison was with a no intervention group and in one it was with usual care).
Promotion of screening mammography and treatment adherence (3 studies).
Stage-based versus non stage-based interventions (1 study): a significant difference in favour of the stage-based intervention was reported for this one study.
Stage-based intervention versus usual care control group (2 studies): one study found a significant difference in favour of the stage-based intervention, but the other did not.
Prevention of smoking and alcohol use (3 studies).
There was a significant difference in favour of the stage-based intervention compared with no intervention for scores on heavy alcohol use in one study, but no differences for measures of alcohol frequency or quantity. No significant between-group differences were observed in a second study of alcohol prevention. In the third study, which used a usual health education comparison group, there were no significant between-group differences in smoking outcomes.