The Hutchinson Smoking Prevention Project trial: design and baseline characteristics

School-based programmes for preventing smoking

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.

A literature review of randomized controlled trials of the organization of care at the end of life

We searched nine electronic databases for randomized controlled trials (RCTs) about care at the end of life and found 23 RCTs. We assessed their quality using the criteria of the Cochrane Collaboration. The RCTs researched three themes: (a) the effect of providing palliative care through dedicated community teams on quality of life, on the management of symptoms, on satisfaction with care, on the duration of the palliative period, and on place of death; (b) the effects of specific palliative care interventions-advanced planning of care for the end of life, patient-held records, providing quality-of-life data to patients and physicians, grief education for relatives, palliative care education for nurses, and palliative care for patients with dementia; and (c) the costs of palliative compared to conventional care. We identify difficulties in conducting research on palliative care and solutions and discuss future possible research themes.

The role of schoolmates' smoking and non-smoking in adolescents' smoking transitions: a longitudinal study

AIMS

The first longitudinal investigation of the extent to which same-age and older schoolmates' smoking and non-smoking are associated with adolescents' smoking transitions during three grade intervals.

DESIGN

Same-age and older schoolmates' smoking and non-smoking were assessed when adolescents were at grades 5 (age 10), 7 (age 12) and 9 (age 14). Adolescents' smoking transitions were assessed at three grade intervals: 5th-7th (age 10-12), 7th-9th (age 12-14) and 9th-12th (age 14-17).

SETTING

Forty Washington State school districts.

PARTICIPANTS AND MEASUREMENTS

Smoking questionnaire data were gathered on a cohort of adolescents (n = 4354 for same-age schoolmate analysis; n = 1833 for older schoolmate analysis) that was 49% female and 91% Caucasian.

FINDINGS

No significant evidence that same-age schoolmates' smoking or non-smoking was associated with any of the adolescent smoking transitions at any of the three grade intervals. In contrast, the probability that each older schoolmate's smoking was associated with the adolescent making the transition to trying smoking was 1% (95% CI: 0.4%, 1.5%) and with the transition from trying to monthly smoking was also 1% (95% CI: 0.2%, 2.0%) during the 7th-9th grade (age 12-14) interval. Moreover, each older schoolmate's non-smoking was associated with a 1.001-1.006 (all P < 0.05) relative risk of an adolescent not trying smoking or escalating from trying to monthly smoking at several grade intervals.

CONCLUSIONS

Interventions should perhaps focus on the influence of both smoking and non-smoking older schoolmates during late childhood and early adolescence.

Changes in the influence of parents' and close friends' smoking on adolescent smoking transitions

This paper examined changes in the influence of parents' and close friends' smoking on smoking transitions occurring over the course of adolescence, using a large (N=6,006) longitudinal study. The three grade periods were 5th to 7th (ages 10-12), 7th to 9th (ages 12-14), and 9th to 12th grade (ages 14-17). Smoking transitions examined were: (1) never to trying, (2) trying to monthly, and (3) monthly to daily. Results showed that the influence of parents' smoking was substantial for all three transitions during most of the grade periods and, for the transition from monthly to daily smoking, increased (p=.006) during adolescence. In contrast, the influence of close friends' smoking was strongest for the transition to trying smoking and did not significantly change (all p>.05) for any of the smoking transitions as the adolescent became older. In conclusion, the influence of close friends' smoking on smoking transitions might be stable during adolescence whereas the influence of parents' smoking on the transition to daily smoking might markedly increase across adolescence.

Close friends', parents', and older siblings' smoking: reevaluating their influence on children's smoking

A number of longitudinal studies have explored the role of friends', parents', and older siblings' smoking in children's smoking acquisition. A reasonable implication of this previous research is that intervention efforts could be beneficially directed toward countering the potential influence of friends' and possibly older siblings' smoking but not parents' smoking. However, methodological limitations of this previous research motivated our reevaluation of the role of friends', parents', and older siblings' smoking in children's smoking. Close friends' smoking status was assessed when children were in 5th grade, whereas parents' and older siblings' smoking status was assessed when children were in 3rd grade. The outcome, children's daily smoking status, was assessed in 12th grade. The setting was 40 Washington state school districts that participated in the long-term Hutchinson Smoking Prevention Project. Participants were the 4,576 families for whom close friends', parents', and older siblings' smoking status as well as children's smoking status were available. The probability that each close friend's smoking influenced the child to smoke daily was 9% (95% CI = 6%-12%), the probability that each parent's smoking influenced the child to smoke daily was 11% (95% CI = 9%-14%), and the probability that each older sibling's smoking influenced the child to smoke daily was 7% (95% CI = 1%-13%). These results suggest that close friends', parents', and siblings' smoking were similarly important influences on children's smoking. Family-focused interventions could be a valuable future direction of prevention research.

School-based programmes for preventing smoking

BACKGROUND

Smoking rates in adolescents are rising in some countries. Helping young people to avoid starting smoking is a widely endorsed goal of public health, but there is uncertainty about how to do this. Schools provide a route for communicating with a large proportion of young people, and school-based programmes for smoking prevention have been widely developed and evaluated.

OBJECTIVES

To review all randomized controlled trials of behavioural interventions in schools to prevent children (aged 5 to12) and adolescents (aged 13 to18) starting smoking.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) and the Cochrane Tobacco Addiction Group's Specialized Register, MEDLINE, EMBASE, PsyclNFO, ERIC, CINAHL, Health Star, Dissertation Abstracts and studies identified in the bibliographies of articles. Individual MEDLINE searches were made for 133 authors who had undertaken randomized controlled trials in this area.

SELECTION CRITERIA

Types of studies: those in which individual students, classes, schools, or school districts were randomized to the intervention or control groups and followed for at least six months.

TYPES OF PARTICIPANTS

Children (aged 5 to12) or adolescents (aged 13 to18) in school settings. Types of interventions: Classroom programmes or curricula, including those with associated family and community interventions, intended to deter use of tobacco. We included programmes or curricula that provided information, those that used social influences approaches, those that taught generic social competence, and those that included interventions beyond the school into the community. We included programmes with a drug or alcohol focus if outcomes for tobacco use were reported. Types of outcome measures: Prevalence of non-smoking at follow up among those not smoking at baseline. We did not require biochemical validation of self-reported tobacco use for study inclusion.

DATA COLLECTION AND ANALYSIS

We assessed whether identified citations were randomized controlled trials. We assessed the quality of design and execution, and abstracted outcome data. Because of the marked heterogeneity of design and outcomes, we computed pooled estimates only for those trials that could be analyzed together and for which statistical data were available. We predominantly synthesized the data using narrative systematic review. We grouped studies by intervention method (information; social competence; social influences; combined social influences/social competence; multi-modal programmes). Within each group, we placed them into three categories (low, medium and high risk of bias) according to validity using quality criteria for reported study design.

MAIN RESULTS

Of the 94 randomized controlled trials identified, we classified 23 as category one (most valid). There was one category one study of information-giving and two of teaching social comeptence. There were thirteen category one studies of social influences interventions. Of these, nine found some positive effect of intervention on smoking prevalence, and four failed to detect an effect on smoking prevalence. The largest and most rigorous study, the Hutchinson Smoking Prevention Project, found no long-term effect of an intensive eight-year programme on smoking behaviour. There were three category one RCTs of combined social influences and social competence interventions: one provided significant results and one only for instruction by health educators compared to self-instruction. There was a lack of high quality evidence about the effectiveness of combinations of social influences and social competence approaches. There was one category one study providing data on social influences compared with information giving. There were four category one studies of multi-modal approaches but they provided limited evidence about the effectiveness of multi-modal approaches including community initiatives.

AUTHORS' CONCLUSIONS

There is one rigorous test of the effects of information-giving about smoking. There are well-conducted randomized controlled trials to test the effects of social influences interventions: in half of the group of best quality studies those in the intervention group smoke less than those in the control, but many studies failed to detect an effect of the intervention. There are only three high quality RCTs which test the effectiveness of combinations of social influences and social competence interventions, and four which test multi-modal interventions; half showed significant positive results.

Childhood friends who smoke: do they influence adolescents to make smoking transitions?

This study investigated longitudinally the extent to which childhood friends who smoke influence adolescents' smoking transitions, and compared that influence with that of parents who smoke. In a sample of 4744 children, results showed that the probability, per close friend, that a smoking close friend influenced the adolescent to make the first transition to trying smoking was 38% (95% CI: 28%, 46%); to make the second transition from trying to monthly smoking, 10% (95% CI: 5%, 15%); and to make the third transition from monthly to daily smoking, 11% (95% CI: 5%, 17%). Compared to parents' smoking, close friends' smoking was 12% (p=0.03) more influential for the first transition, no different for the second transition (p=0.53), and 16% (p=0.01) less influential for the third transition. Results provide new evidence suggesting that childhood close friends who smoke influence not only initiation but also escalation of adolescents' smoking. Results also confirmed the important role of parents' smoking. Targeting both childhood close friends' and parents' smoking would be valuable in prevention research.

Adolescent and young adult tobacco prevention and cessation: current status and future directions

OBJECTIVE

To summarise the evidence on adolescent and young adult prevention and cessation, and provide future directions for research.

DATA SOURCES

Data were collected from published literature. Searches for adolescent prevention were conducted using PubMed, PsycInfo, and ERIC; and for cessation, PubMed, and two major reviews that span January 1978 to May 2002. PubMed, PsychInfo, and SCCI were searched for young adults from January 1990 to May 2002.

STUDY SELECTION

Data included smoking prevention studies published from January 1990 to May 2002 and conducted in the USA; all identified smoking cessation studies for adolescents. Young adult data were limited to initiation and cessation studies.

DATA EXTRACTION

Extraction of data was by consensus of the authors.

DATA SYNTHESIS

Results of the review are qualitative in nature using a consensus approach of the authors.

CONCLUSIONS

School based curricula alone have been generally ineffective in the long term in preventing adolescents from initiating tobacco use but are effective when combined with other approaches such as media and smoke-free policies. Prevention research should consider multiple approaches and the social conditions that influence the development of youth problem behaviours including tobacco use. Because youth smoking cessation has been understudied to date, scientifically rigorous adolescent smoking cessation studies need to be conducted with attention to high risk smokers and less than daily smokers. Tobacco prevention and cessation for young adults needs focused attention. Prevention and cessation programmes need to address other tobacco products in addition to cigarettes.

Effectiveness of the "Smoke-Free Class Competition" in delaying the onset of smoking in adolescence

BACKGROUND

This paper examines the effectiveness of the "Smoke-Free Class Competition" in delaying the onset of smoking in adolescence. Each participating class must decide if they want to be a "smoke-free class" for the 6-month period from fall to spring. Classes monitor their (non-)smoking behavior and report it to the teacher regularly. Classes in which pupils refrain from smoking for this period of time participate in a prize draw, in which they can win a number of attractive prizes.

METHODS

To evaluate the effectiveness of the competition, a sample of 131 participating and nonparticipating classes (number of pupils 2,142; mean age 12.9 years, SD = 0.98) was compared with regard to their smoking behavior. Smoking status was determined by self-assessment on three occasions: (a) prior to the beginning of the competition, (b) 1 month after the competition, and (c) 1 year after the start of the competition.

RESULTS

From pretest to posttest smoking increased by 7.5% in the comparison group, while it decreased by 0.2% in the intervention group (OR = 2.19; P < 0.001). In the follow-up measurement, a clear increase in smoking prevalence occurs in all groups; however, the pupils in the intervention condition still have a significant lower increase of smoking (OR = 1.45; P < 0.01). Moreover, with regard to the nonsmokers at baseline, pupils in the comparison group showed significantly higher prevalences in smoking than the intervention group in the postmeasurement, 7.8 versus 13.9% (OR = 1.98; P < 0.001), as well as in the in the follow-up-measurement, 17 versus 21.3% (OR = 1.36; P < 0.05).

CONCLUSIONS

The results suggest that the participation in the competition could delay the onset of smoking in adolescence.

School-based programmes for preventing smoking

BACKGROUND

Smoking rates in adolescents are rising. Helping young people to avoid starting smoking is a widely endorsed goal of public health, but there is uncertainty about how to do this. Schools provide a route for communicating with a large proportion of young people, and school-based programmes for smoking prevention have been widely developed and evaluated.

OBJECTIVES

To review all randomised controlled trials of behavioural interventions in schools to prevent children (aged 5 to12) and adolescents (aged 13 to18) starting smoking.

SEARCH STRATEGY

We searched The Cochrane Controlled Trials and Tobacco Review group registers, MEDLINE, EMBASE, Psyclnfo, ERIC, CINAHL, Health Star, Dissertation Abstracts and studies identified in the bibliographies of articles. Individual MEDLINE searches were made for 133 authors who had undertaken randomised controlled trials in this area.

SELECTION CRITERIA

Types of studies: those in which individual students, classes, schools, or school districts were randomised to the intervention or control groups and followed for at least six months.

TYPES OF PARTICIPANTS

Children (aged 5 to12) or adolescents (aged 13 to18) in school settings. Types of interventions: Classroom programmes or curricula, including those with associated family and community interventions, intended to deter use of tobacco. We included programmes or curricula that provided information, those that used social influences approaches, those that taught generic social competence, and those that included interventions beyond the school into the community. We included programmes with a drug or alcohol focus if outcomes for tobacco use were reported. Types of outcome measures: Prevalence of non-smoking at follow-up among those not smoking at baseline. We did not require biochemical validation of self-reported tobacco use for study inclusion.

DATA COLLECTION AND ANALYSIS

We assessed whether identified citations were randomised controlled trials. We assessed the quality of design and execution, and abstracted outcome data. Because of the marked heterogeneity of design and outcomes, we did not perform a meta-analysis. We synthesised the data using narrative systematic review. We grouped studies by intervention method (information; social competence; social influences; combined social influences/social competence and multi-modal programmes). Within each category, we placed them into three groups according to validity using quality criteria for reported study design.

MAIN RESULTS

Of the 76 randomised controlled trials identified, we classified 16 as category one (most valid). There were no category one studies of information giving alone. There were fifteen category one studies of social influences interventions. Of these, eight showed some positive effect of intervention on smoking prevalence, and seven failed to detect an effect on smoking prevalence. The largest and most rigorous study, the Hutchinson Smoking Prevention Project, found no long-term effect of an intensive 8-year programme on smoking behaviour. There was a lack of high quality evidence about the effectiveness of combinations of social influences and social competence approaches. There was limited evidence about the effectiveness of multi-modal approaches including community initiatives.

REVIEWER'S CONCLUSIONS

There is no rigorous test of the effects of information giving about smoking. There are well-conducted randomised controlled trials to test the effects of social influences interventions: in half of the group of best quality studies those in the intervention group smoke less than those in the control, but many studies showed no effect of the intervention. There is a lack of high-quality evidence about the effectiveness of combinations of social influences and social competence interventions, and of multi-modal programmes that include community interventions.