Cochrane
Database Syst Rev. 2013 Apr 30;4:CD001293. doi: 10.1002/14651858.CD001293.pub3.
Thomas RE, McLellan J, Perera R.
Department of Family Medicine, Faculty of Medicine, University of Calgary, Calgary, Canada. rthomas@ucalgary.ca.
Department of Family Medicine, Faculty of Medicine, University of Calgary, Calgary, Canada. rthomas@ucalgary.ca.
Abstract
BACKGROUND:
Helping young people to avoid starting smoking
is a widely endorsed public health goal, and schools provide a route to
communicate with nearly all young people. School-based interventions have been
delivered for close to 40 years.
OBJECTIVES:
The primary aim of this review was to determine
whether school smoking interventions prevent youth from starting smoking. Our
secondary objective was to determine which interventions were most effective.
This included evaluating the effects of theoretical approaches; additional
booster sessions; programme deliverers; gender effects; and multifocal
interventions versus those focused solely on smoking.
SEARCH METHODS:
We searched the Cochrane Central Register of
Controlled Trials (CENTRAL), the Cochrane Tobacco Addiction Group's Specialised
Register, MEDLINE, EMBASE, PsycINFO, ERIC, CINAHL, Health Star, and
Dissertation Abstracts for terms relating to school-based smoking cessation
programmes. In addition, we screened the bibliographies of articles and ran
individual MEDLINE searches for 133 authors who had undertaken randomised
controlled trials in this area. The most recent searches were conducted in
October 2012.
SELECTION CRITERIA:
We selected randomised controlled trials (RCTs)
where students, classes, schools, or school districts were randomised to
intervention arm(s) versus a control group, and followed for at least six
months. Participants had to be youth (aged 5 to 18). Interventions could be any
curricula used in a school setting to deter tobacco use, and outcome measures
could be never smoking, frequency of smoking, number of cigarettes smoked, or
smoking indices.
DATA COLLECTION AND ANALYSIS:
Two reviewers independently assessed studies for
inclusion, extracted data and assessed risk of bias. Based on the type of
outcome, we placed studies into three groups for analysis: Pure Prevention
cohorts (Group 1), Change in Smoking Behaviour over time (Group 2) and Point
Prevalence of Smoking (Group 3).
MAIN RESULTS:
One hundred and thirty-four studies involving
428,293 participants met the inclusion criteria. Some studies provided data for
more than one group.Pure Prevention cohorts (Group 1) included 49 studies (N =
142,447). Pooled results at follow-up at one year or less found no overall
effect of intervention curricula versus control (odds ratio (OR) 0.94, 95%
confidence interval (CI) 0.85 to 1.05). In a subgroup analysis, the combined
social competence and social influences curricula (six RCTs) showed a
statistically significant effect in preventing the onset of smoking (OR 0.49,
95% CI 0.28 to 0.87; seven arms); whereas significant effects were not detected
in programmes involving information only (OR 0.12, 95% CI 0.00 to 14.87; one
study), social influences only (OR 1.00, 95% CI 0.88 to 1.13; 25 studies), or
multimodal interventions (OR 0.89, 95% CI 0.73 to 1.08; five studies). In
contrast, pooled results at longest follow-up showed an overall significant
effect favouring the intervention (OR 0.88, 95% CI 0.82 to 0.96). Subgroup
analyses detected significant effects in programmes with social competence
curricula (OR 0.52, 95% CI 0.30 to 0.88), and the combined social competence
and social influences curricula (OR 0.50, 95% CI 0.28 to 0.87), but not in
those programmes with information only, social influence only, and multimodal
programmes.Change in Smoking Behaviour over time (Group 2) included 15 studies
(N = 45,555). At one year or less there was a small but statistically
significant effect favouring controls (standardised mean difference (SMD) 0.04,
95% CI 0.02 to 0.06). For follow-up longer than one year there was a
statistically nonsignificant effect (SMD 0.02, 95% CI -0.00 to
0.02).Twenty-five studies reported data on the Point Prevalence of Smoking
(Group 3), though heterogeneity in this group was too high for data to be
pooled.We were unable to analyse data for 49 studies (N = 152,544).Subgroup
analyses (Pure Prevention cohorts only) demonstrated that at longest follow-up
for all curricula combined, there was a significant effect favouring adult
presenters (OR 0.88, 95% CI 0.81 to 0.96). There were no differences between
tobacco-only and multifocal interventions. For curricula with booster sessions
there was a significant effect only for combined social competence and social
influences interventions with follow-up of one year or less (OR 0.50, 95% CI
0.26 to 0.96) and at longest follow-up (OR 0.51, 95% CI 0.27 to 0.96). Limited
data on gender differences suggested no overall effect, although one study
found an effect of multimodal intervention at one year for male students.
Sensitivity analyses for Pure Prevention cohorts and Change in Smoking
Behaviour over time outcomes suggested that neither selection nor attrition
bias affected the results.
AUTHORS' CONCLUSIONS:
Pure Prevention cohorts showed a significant
effect at longest follow-up, with an average 12% reduction in starting smoking
compared to the control groups. However, no overall effect was detected at one
year or less. The combined social competence and social influences
interventions showed a significant effect at one year and at longest follow-up.
Studies that deployed a social influences programme showed no overall effect at
any time point; multimodal interventions and those with an information-only
approach were similarly ineffective.Studies reporting Change in Smoking
Behaviour over time did not show an overall effect, but at an intervention
level there were positive findings for social competence and combined social
competence and social influences interventions.
Update of
