Child-Adult Contract for Prevention of Tobacco Use: "As-Treated" Analysis of a Cluster Randomized Controlled Trial (the TOPAS Study) at 3-Year Follow-Up

To estimate the effect of a 3-year commitment to remain tobacco free on tobacco uptake among high school students in Sweden. The commitment is developed in the form of a contract between a child and a significant adult, constituting the core component of Tobacco-free Duo (T-Duo), a Swedish school-based tobacco prevention program. Secondary analysis of data from a cluster randomized controlled trial. Participants were 586 students in high schools assigned to the intervention arm of T-Duo. At inception, participants attended grade 7 (i.e., age 12-13). Only students who were tobacco naïve at baseline for the respective outcome and participated in all follow-ups were included. The exposure was defined as signing a 3-year contract with a significant adult, categorized as "stable contract" (3 years contract with the same contract partner), "unstable" (signed a contract sometime during follow-up but this was not sustained over time and/or with the same partner), and "no contract" at all during the intervention period. The primary outcome was having never tried cigarette smoking at the end of grade 9. Exposure and outcomes were self-reported in yearly questionnaires. Of 586 students, 321 (55%) held a stable contract, 204 (35%) an unstable contract, and 61 (10%) did not sign a contract at all. At the end of grade 9 (age 15-16), the relative risk (RR) to remain cigarette free was 1.11 (95% CI 1.00-1.22) (Number Needed to Treat = 10) among students in any type of contract compared to students that did not write a contract at all. The RRs for remaining tobacco free (secondary outcomes) ranged from 1.07 (0.98-1.16) for regular snus use to 1.16 (1.00-1.35) for any type of tobacco use. A commitment to remain tobacco free through a child-adult contract seems to exert a preventive effect on the uptake of tobacco use among Swedish adolescents over 3 school years. The current findings apply to a selected sample of both schools and students. Registration: Current Controlled Trials ISRCTN52858080 Date: January 4, 2019, retrospectively registered.

From a teacher and school leader perspective: What happened with smoking rules and practices during a three-year smoking preventive intervention? - Findings from the X:IT II study

BACKGROUND

School-based smoking preventive interventions are most effective if they consist of multiple components; one of them being strict anti-smoking rules, i.e., no smoking by anyone at any location during school hours. However, there is a lack of in-depth knowledge about how smoking practices and rules about smoking actually change over time. Therefore, the purpose of this study was to examine how smoking practices changed during a three-year period in which a smoking preventive intervention with strict anti-smoking rules was implemented at schools.

METHODS

We used data from 46 Danish schools that were enrolled in the evaluation of the X:IT II study - a smoking preventive intervention with three main components: one of them being strict anti-smoking rules. We collected questionnaire data among school employees at four timepoints from the autumn of 2017 until April 2020. The questionnaire covered topics regarding students' and employees' tobacco patterns at the school, control with smoking, and aspects of the intervention delivery.

RESULTS

Over time, student smoking rules got stricter; from three out of four at baseline to almost all schools having rules about no student smoking during school hours three years later. Employee smoking rules also changed, although not as much as student rules. Overall, smoking at school grounds seemed to decline - however, student smoking at other locations increased, hence, violating the rule about no smoking during school hours. Enforcement of smoking rules also increased over time.

CONCLUSION

Although implementing and enforcing new rules in a school setting may be difficult, it seemed that most schools in the X:IT II study changed their rules and smoking practices for both students and employees over the three-year intervention period. It seemed, however, that students relocated their smoking to other places than the school or just outside school grounds. Implications of these findings are important to consider in future interventions, i.e., students leaving school during school hours to smoke and the physical separation between those who smoke and those who do not.

Effectiveness of the multi-component intervention 'Focus' on reducing smoking among students in the vocational education setting: a cluster randomized controlled trial

BACKGROUND

Social inequality in smoking remains an important public health issue. Upper secondary schools offering vocational education and training (VET) comprise more students from lower socioeconomic backgrounds and have higher smoking prevalence than general high schools. This study examined the effects of a school-based multi-component intervention on students' smoking.

METHODS

A cluster randomized controlled trial. Eligible participants were schools offering VET basic courses or preparatory basic education in Denmark, and their students. Schools were stratified by subject area and eight schools were randomly allocated to intervention (1,160 invited students; 844 analyzed) and six schools to control (1,093 invited students; 815 analyzed). The intervention program comprised smoke-free school hours, class-based activities, and access to smoking cessation support. The control group was encouraged to continue with normal practice. Primary outcomes were daily cigarette consumption and daily smoking status at student level. Secondary outcomes were determinants expected to impact smoking behavior. Outcomes were assessed in students at five-month follow-up. Analyses were by intention-to-treat and per protocol (i.e., whether the intervention was delivered as intended), adjusted for covariates measured at baseline. Moreover, subgroup analyses defined by school type, gender, age, and smoking status at baseline were performed. Multilevel regression models were used to account for the cluster design. Missing data were imputed using multiple imputations. Participants and the research team were not blinded to allocation.

RESULTS

Intention-to-treat analyses showed no intervention effect on daily cigarette consumption and daily smoking. Pre-planned subgroup analyses showed statistically significant reduction in daily smoking among girls compared with their counterparts in the control group (OR = 0.39, 95% CI: 0.16, 0.98). Per-protocol analysis suggested that schools with full intervention had higher benefits compared with the control group (daily smoking: OR = 0.44, 95% CI: 0.19, 1.02), while no marked differences were seen among schools with partial intervention.

CONCLUSION

This study was among the first to test whether a complex, multicomponent intervention could reduce smoking in schools with high smoking risk. Results showed no overall effects. There is a great need to develop programs for this target group and it is important that they are fully implemented if an effect is to be achieved.

TRIAL REGISTRATION

https://www.isrctn.com/ISRCTN16455577 , date of registration 14/06/2018.

Socioeconomic Differences in Cigarette Smoking and Alternative Tobacco Product Use Among Adolescents in a School-Based Smoking Preventive Intervention: Findings From the Second Year of the X:IT II Study

Background

Health interventions may differently impact adolescents from diverse backgrounds. This study examined whether a smoking preventive intervention was equally effective in preventing cigarette smoking and use of alternative tobacco products (ATPs, i.e., snus, e-cigarettes, and waterpipe) among students from different socioeconomic backgrounds, i.e., occupational social classes (OSC).

Methods

Data was from the school-based intervention X:IT II targeting 13- to 15-year-olds Danes. The intervention focused on three main components: smoke-free school time, smoke-free curriculum, and parental involvement. In total, 46 schools were included at baseline (N = 2,307, response rate = 86.3%). Using a difference-in-differences approach, changes in current smoking and ever use of ATPs were estimated among students in high versus low OSC at second follow-up. Analyses were based on available cases (N = 826) and multiple imputations of missing data at the second follow-up (N = 1,965).

Results

At baseline (age 13), 1.0% of students from high OSC and 4.8% from low OSC currently smoked cigarettes, while this was the case among 24.5 and 25.6%, respectively, at the second follow-up (age 15). Estimates indicated that social inequalities in current smoking diminished over time (p < 0.001). Regarding ATPs, 10.0% of high OSC students and 13.9% of low OSC students had ever used ATPs at baseline, while at second follow-up, 46.8 and 60.8%, respectively, had ever used ATPs. Estimates indicated that social inequalities in ever use of ATPs widened over time (p < 0.001).

Conclusions

The X:IT II intervention seemed to diminish socioeconomic disparities in smoking over the study period. Meanwhile, social inequalities in ever use of ATPs increased. Therefore, besides focusing on narrowing the social disparities in cigarette smoking, future efforts may, to a larger extent, focus on adolescents' use of ATPs.

Evaluation of the Swedish school-based program "tobacco-free DUO" in a cluster randomized controlled trial (TOPAS study). Results at 2-year follow-up

Friends' and parents' tobacco use are strong predictors of tobacco uptake among adolescents, however the effectiveness of interventions based on public commitments and agreements to remain tobacco-free are not established. Here, we evaluated the effectiveness of the school-based Swedish program Tobacco-Free Duo (T-Duo) in preventing adolescents from initiating tobacco use (TOPAS study). T-Duo is a multi-component intervention witha formal agreement between a student and an adult partner to remain tobacco-free during the entire 3-year study period as core component. The standardized educational component of the same program was used as comparator (control). Primary outcome was the probability to "remain a non-user" of i) cigarettes and secondary outcomes ii) other types of tobacco at second (21-month) follow-up. Analysis was conducted according to Intention To Treat. In total 1776 adolescents (51% female) aged 12-13 in grade 7 from 34 participating high schools in Sweden were included at baseline in 2018, of which 1489 were retained after 21 months. The Risk Ratio (RR) of not having tried cigarettes 21-months after initiation of the intervention was 1.03(CI 0.98-1.08), Bayes Factor(BF) = 0.93, Absolute Risk Difference(ARD) = 3.1%. Similar associations were found for never smoked a whole cigarette and never use of other tobacco/nicotine products. There was a minimal reduction of tobacco use initiation among Swedish adolescents assigned to a multi-component intervention (T-Duo) compared to those assigned to standardized classroom education after 2 schoolyears. However, for most outcomes' findings were inconclusive and not reliably different from zero. Trial registration: ISRCTN5285808 (doi:https://doi.org/10.1186/ISRCTN52858080); Study protocol: DERR1-https://doi.org/10.2196/21100. Registration: Current Controlled Trials ISRCTN52858080 Date: January 4, 2019, retrospectively registered. Protocol: Galanti, M.R., Pulkki-Brännström, A.-M., Nilsson, M., 2020. Tobacco-free duo adult-child contract for prevention of tobacco use among adolescents and parents: protocol for a mixed-design evaluation. JMIR Res. Protoc. 9, e21100. doi:10.2196/21100.

Who are the young users of tobacco products? Prevalence and characteristics of Danish adolescents who have either smoked cigarettes, used alternative tobacco products, or used both

Aims:

We examined characteristics (smoking in social relations, binge drinking, and well-being measures) of Danish 13-year-olds in relation to their tobacco use patterns. Ever use of cigarettes exclusively, ever use of alternative tobacco products (ATPs; e-cigarettes, snus, or waterpipe) exclusively, and use of both cigarettes and ATPs were studied.

Methods:

We used self-reported data from students at 46 Danish schools in 2017 comprising 2,307 students (response rate = 86%). Multi-level logistic regression analyses were used to examine the associations between student characteristics and the odds for having ever used any tobacco products, smoked cigarettes exclusively, used ATPs exclusively, or used both cigarettes and ATPs compared with never use of any tobacco products. Unadjusted estimates and estimates adjusted for gender were reported.

Results:

A significant minority of youth (13.2%) had used one or more tobacco products. Of these, 2.0% had exclusively smoked cigarettes, 7.2% had exclusively used ATPs, and 4.0% had used both. Findings showed that all included characteristics (families’ and friends’ smoking, binge drinking, and well-being characteristics) were associated with using any tobacco product; however, students with friends who smoked, had been binge drinking, and had low well-being at home had notably higher odds for having both smoked cigarettes and used ATPs compared to the other tobacco use patterns.

Conclusion:

ATPs were popular among Danish adolescents compared with conventional cigarettes. Thus, prevention efforts among adolescents should not merely focus on the health risks of conventional cigarette smoking but also on ATPs. Students with diverse tobacco use patterns were similar on various characteristics. However, findings indicate that adolescents who had used both conventional cigarettes and ATPs constitute a more risk-averse group in special need of prevention efforts. Gender did not markedly influence the results. These findings may help future strategies aiming at the youngest adolescents at risk of using tobacco products.

Socio-economic differences in smoking among adolescents in a school-based smoking intervention: The X:IT II study

Aims: Socio-economic inequalities in health behaviour may be influenced by health interventions. We examined whether the X:IT II intervention, aiming at preventing smoking in adolescence, was equally effective among students from different occupational social classes (OSC). Methods: We used data from the multi-component school-based smoking preventive intervention X:IT II, targeting 13- to 15-year-olds in Denmark. The intervention was tested in 46 schools with 2307 eligible students at baseline (response rate=86.6%) and had three main intervention components: smoke-free school time, smoke-free curriculum and parental involvement. We used a difference-in-difference design and estimated the change in current smoking after the first year of implementation in high versus low OSC. Analyses were based on available cases (N=1190) and imputation of missing data at follow-up (N=1967). Results: We found that 1% of the students from high OSC and 4.9% from low OSC were smokers at baseline (imputed data), and 8.2% of the students from high OSC and 12.2% from low OSC were smokers at follow-up. Difference-in-difference estimates were close to zero, indicating no differential trajectory. Conclusions: As intended, the X:IT II intervention, designed to apply equally to students from all socio-economic groups, did not seem to create different trajectories in current smoking among adolescents in high and low socio-economic groups. To diminish social inequality in health, future studies should carefully consider the ability to affect all socio-economic groups equally, or even to appeal mainly to participants from lower socio-economic groups, as they are often the ones most in need of intervention.

Associations between mental health and sociodemographic characteristics among schoolchildren. A cross-sectional survey in Denmark 2019

Aims: We aimed to investigate associations between mental health and sociodemographic characteristics among schoolchildren in Denmark. Methods: We performed a cross-sectional survey from January to October 2019 among 4th to 9th graders (N=1247) based on pilot data from a nationwide research project Stress-free Everyday LiFe for Children and Adolescents REsearch (SELFCARE). We assessed mental health using the five-item World Health Organization Well-Being Index and the self-report version of the Strengths and Difficulties Questionnaire. We investigated associations between mental health and sex, age in terms of grade, type of school, family setting and geographic region using regression analysis. Results: Mental health was poorer among girls in the older classes compared to girls in 4th grade, and better among boys in the older classes compared to boys in 4th grade. We found no difference in mental health among schoolchildren in municipal and private schools. Mental health was poorer among both girls and boys living alternately with their parents compared to residing with both of them. Mental health varied across geographic regions. Conclusions: We found associations between mental health and sex, age in terms of grade, family setting and geographic region.

The Cigarette Smoking Initiation and Continuation in Adolescents Undergoing a Long-Term Behavioral Intervention

INTRODUCTION

Targeting adolescents' smoking reduces its burden on health systems. We investigated the effects of the first multidisciplinary community-based lifestyle intervention in the Eastern Mediterranean region, on smoking initiation, continuation, and risk of current smoking in Iranian adolescents.

METHODS

The current analyses were conducted on 945 nonsmoker adolescents (12-18 years) who participated in Phase II of Tehran Lipid and Glucose Study (TLGS) and were examined four times in 12 years. The lifestyle intervention including school-based and public programs was implemented, focusing on all components of healthy lifestyle. Using a two-step cluster analysis, families were classified as high and low risk, based on parental risk factors of adolescents' smoking. Participants who failed to complete all the follow-ups (n = 99) and those with missing smoking data were excluded. Subsequently, 872 adolescents (538 control, 334 intervention) were included in the Cox model on smoking initiation, and 674 adolescents (414 control, 260 intervention) were included in the logistic regression on smoking status.

RESULTS

Mean age of adolescents was 15.08 ± 1.94 years at baseline. The hazard of the smoking initiation was significantly lower in the intervention (hazard ratio = 0.71, 95% confidence interval: 0.51-0.99; p = .044) compared with control group. At the end of the fourth follow-up, intervention reduced the odds of current cigarette smoking by 29%. Within the intervention group, the high-risk cluster was at a 35% lower risk of initiating smoking and had 37% lower odds of becoming a current smoker. However, the intervention could not make a difference in preventing those who initiated smoking from maintaining it during the follow-ups.

CONCLUSIONS

Our results demonstrate that lifestyle modification programs targeting at-risk populations could reduce risk of smoking initiation and current smoking in adolescents in long term.

IMPLICATIONS

Experiencing cigarette smoking at the critical period of adolescence could result in adulthood habitual smoking. Therefore, identifying adolescents who are more at risk of smoking initiation and implementing targeted interventions are of great importance in public health. Our findings highlight the long-term effectiveness of a multidisciplinary community-based behavioral intervention on forming smoking behaviors in adolescents. The current intervention was successful in reducing smoking uptake in adolescents living in high-risk families.

Assessing Differences in the Implementation of Smoke-Free Contracts-A Cross-Sectional Analysis from the School Randomized Controlled Trial X:IT

OBJECTIVE

The X:IT study is a school-based smoking preventive intervention that has previously been evaluated in a large randomized controlled trial (RCT) with good effects. However, the actual effect for participating students depends on the individual implementation. The aim of this study was to examine the implementation of smoke-free contract, which is one of the three main intervention components. Specifically, we examined whether it was implemented equally across family occupational social class (OSC), separately for boys and girls, the joint effect of OSC and gender, and the participants' own reasons for not signing a contract.

RESULTS

Overall, the smoke-free contract was well implemented; 81.8% of pupils (total N = 2.015) signed a contract (girls 85.1, boys 78.6%). We found a social gradient among girls; more than 90% were in OSC group I vs. 75% in group VI. Among boys, however, we found no difference across OSC. Boys in all the OSC groups had about half the odds (i.e., medium OSC boys: OR = 0.48 (95% CI: 0.32-0.72) of having a smoke-free contract compared to girls from a high OSC.

CONCLUSION

future interventions should include initiatives to involve families from all OSC groups and allow for different preferences among boys and girls.

Gender differences in attitudes towards a school-based smoking prevention intervention

AIMS

There are well-known gender differences in smoking, including the pattern of use and the effectiveness of smoking prevention programs. However, little is known about the differences between boys and girls in their attitudes towards smoking prevention interventions. This study explores gender differences in attitudes towards a school-based intervention to prevent smoking.

METHODS

We used data from the X:IT II intervention study conducted in 46 Danish elementary schools.

RESULTS

Compared to boys, girls were more positive towards smoke-free school time, both concerning rules for teachers smoking (odds ratio (OR) = 1.69, 95% confidence interval (CI): 1.35-2.12) and for students smoking (OR = 1.41, 95% CI: 1.13-1.76). No difference was observed in students signing the smoke-free agreement. However, a larger proportion of girls reported that the agreement was a good occasion to talk about smoking with their parents (OR = 1.36, 95% CI: 1.13-1.76). Girls were also more positive towards the smoke-free curriculum (OR = 1.52, 95% CI: 1.19-1.94).

CONCLUSIONS

This study showed that girls were, overall, more positive towards the components of the smoking preventive intervention. Our findings highlight the importance of considering differences in intervention preferences for boys and girls in future health prevention initiatives.

Estimating future smoking in Danish youth – effects of three prevention strategies

Aims: Preventing smoking and aiding cessation among youth and young adults carries the possibility of reducing future smoking prevalence significantly. This paper estimates the impact on future smoking prevalence of 25 year olds by increasing tobacco prices, securing indoor smoke-free homes and implementing school-based multi-tiered interventions. Methods: Utilizing a multi-state Markov model, a status quo projection of the smoking prevalence from years 2017 to 2030 were compared with projections of the smoking prevalence in 2030 considering the impact of the three prevention strategies. Results: In a status quo projection, 27.0% of Danish 25-year-old females are expected to be smokers in 2030, while 13.2% would be smokers in 2030 were all three prevention strategies in effect from 2019. By itself, increasing tobacco prices by 50% reduced the prevalence of smokers among 25-year-old females to 14.8% in 2030, a relative reduction of 47.5%. For 25-year-old males in 2030 the reductions were similar, with a prevalence of 16.6% when all three prevention strategies were in effect, a relative reduction of 51.5%. Conclusions: Implementing increasing tobacco prices, indoor smoke-free homes and school-based multi-tiered interventions in Denmark is likely to significantly decrease youth smoking prevalence in the future. However, these three strategies will not produce a smoke-free generation without other initiatives.

Trends in socioeconomic differences in daily smoking among 15-year-old Danes 1991–2014

Aim: To examine trends in socioeconomic differences in daily smoking among 15-year-old Danes between 1991–2014, using occupational social class as indicator of socioeconomic status. Methods: The study included 15-year-olds participating in seven Danish Health Behaviour in School-aged Children studies between 1991–2014, n = 8,641. The analyses focused on absolute socioeconomic differences (prevalence difference between low and high occupational social class) and relative socioeconomic differences communicated by odds ratio for daily smoking. Results: The prevalence of daily smoking declined from 18.6% in 1991 to 4.5% in 2014. Across all surveys, the prevalence was 8.9% in high, 12.8% in middle and 16.5% in low occupational social classes ( p < 0.0001). The absolute socioeconomic differences increased from 1991 to 2006 and declined thereafter. Across all survey years, the odds ratio (95% confidence interval) for daily smoking was 1.40 (1.19–1.65) in middle and 1.90 (1.56-2.32) in low versus high occupational social classes. The statistical interaction between occupational social class and survey year was significant ( p = 0.0404), suggesting increasing relative socioeconomic differences from 1991 to 2014. Conclusions: There was a substantial decline in daily smoking among 15-year-olds between 1991–2014 in all occupational social class groups. The prevalence of daily smoking was highest in the low occupational social class during the entire period. The absolute socioeconomic differences in daily smoking increased between 1991–2006 and declined thereafter. The relative socioeconomic differences increased over 1991–2014. Studies of change in socioeconomic differences over time should address both absolute and relative socioeconomic differences as they may result in different conclusions and because important improvement in prevalence patterns may be disguised by exclusive focus on changes in relative socioeconomic differences.

Study protocol of the X:IT II - a school-based smoking preventive intervention

BACKGROUND

The X:IT intervention, conducted in 2010 to 2013, showed overall smoking preventive effect. However, parts of the intervention appeared less appealing to children from families with lower socioeconomic backgrounds. Therefore, the intervention components were modified and an evaluation of the amended intervention X:IT II is needed to show the effect of this revised intervention and whether children from different social backgrounds benefits equally from the current intervention.

METHODS

Main intervention components are smoke free schools, a curricular component, and parental involvement (smoke free agreements and talks about tobacco). Components have been revised from the first version; 1) previously, schools should be smoke free on the school ground and were encouraged to hide smoking so that it wasn't visible to pupils from the school ground. Now they are encouraged to tighten the rules so that no pupils or teachers smoke during the school day, no matter where they are; 2) the specifically developed educational material (Up in Smoke) has been revised so that all materials are online and all texts has a ARI; 3) the parental involvement is now targeted multiple groups of parents, e.g. parents that are smokers, and parents of children that smoke. Language used is simpler and the website for parents presents very specific examples. X:IT is implemented in 46 Danish public schools from fall 2017 until summer 2020. Data is collected through electronic questionnaires to students and coordinators four times (fall 2017, spring/summer 2018, 2019 and 2020). Further, qualitative interviews and observations are conducted.

DISCUSSION

Prevalence of smoking among Danish adolescents is high compared to other Nordic countries and there is social inequality in smoking, leaving individuals from the lowest social backgrounds at higher risk. Although there has been an overall decline in smoking among Danish adolescents over the last decades, a recent levelling of this development indicates an urgent need for smoking prevention in Denmark. The X:IT intervention has the potential to prevent uptake of smoking among adolescents. However, there is a particular need for evaluating the effectiveness of the revised X:IT intervention, X:IT II, with focus on the effect across socioeconomic groups of adolescents.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN31292019 , date of registration 24/10/2017. Retrospectively registered.

Implementation fidelity and adolescent smoking: The X:IT study-A school randomized smoking prevention trial

BACKGROUND

Assessing the actual implementation of multi-component interventions can provide important knowledge for future interventions. Intervention components may be implemented differently, knowledge about this can provide an understanding of which components are essential and therefore must be included. The aim of this study was to examine the implementation of one, two, or all three main intervention components at the individual level and to assess the association to current smoking among 13 year-olds in the X:IT study.

METHODS

Data stems from a cluster-randomized controlled trial in 94 Danish elementary schools (51 intervention; 43 control schools). Implementation was measured by aspects of adherence, dose, quality of delivery, and participant responsiveness based on questionnaire data from 4161 pupils at baseline (mean-age: 12.5 years) and 3764 pupils at first follow-up eight months later. Coordinator responses from 49 intervention schools were also included. Associations between individual level implementation of the three main components and pupil smoking were examined through a 3-level logistic regression model.

RESULTS

Although implementation fidelity for the three main intervention components was good, only one third (38.8%) of pupils in intervention schools were exposed to full implementation of the intervention. Among these pupils odds ratio for smoking was 0.25 (95% CI: 0.15 - 0.42).

CONCLUSIONS

School-based programs can be very effective if carefully implemented. Future school-based smoking preventive initiatives should include multiple components, and seek to enhance implementation quality of all components.

A Tool to Identify Adolescents at Risk of Cigarette Smoking Initiation

: media-1vid110.1542/5828318368001PEDS-VA_2017-3701Video Abstract OBJECTIVES: To describe the development of a prognostic tool to identify adolescents at risk for transitioning from never to ever smoking in the next year.

METHODS

Data were drawn from the Nicotine Dependence in Teens study, a longitudinal investigation of adolescents (1999 to present). A total of 1294 students initially age 12 to 13 years were recruited from seventh-grade classes in 10 high schools in Montreal. Self-report questionnaire data were collected every 3 months during the 10-month school year over 5 years (1999-2005) until participants completed high school (n = 20 cycles). Prognostic variables for inclusion in the multivariable analyses were selected from 58 candidate predictors describing sociodemographic characteristics, smoking habits of family and friends, lifestyle factors, personality traits, and mental health. Cigarette smoking initiation was defined as taking even 1 puff on a cigarette for the first time, as measured in a 3-month recall of cigarette use completed in each cycle.

RESULTS

The cumulative incidence of cigarette smoking initiation was 16.3%. Data were partitioned into a training set for model-building and a testing set to evaluate the performance of the model. The final model included 12 variables (age, 4 worry or stress-related items, 1 depression-related item, 2 self-esteem items, and 4 alcohol- or tobacco-related variables). The model yielded a c-statistic of 0.77 and had good calibration.

CONCLUSIONS

This short prognostic tool, which can be incorporated into busy clinical practice, was used to accurately identify adolescents at risk for cigarette smoking initiation.

Evaluation of the smoking intervention X:IT after the second year: A randomized controlled trial

Aims:Review studies on the long-term effects of school-based smoking interventions show mixed results. X:IT was a three-year cluster randomized controlled trial to prevent uptake of smoking among Danish students from age 13 years until age 15 years which previously proved effective in preventing smoking after the first year of intervention. The aim of this paper was to conduct the pre-planned analyses of the effects of the X:IT intervention on smoking after the second year. Methods: We used self-reported questionnaire data from students at baseline, first, second, and third follow-up (n at second follow-up=3269, response rate=79.4%). Data from third follow-up were not suitable for analysis. Outcome measure: 'current smoking', dichotomised into smoke daily, weekly, monthly or more seldom versus do not smoke. We performed multilevel, logistic regression analyses of available cases and intention-to-treat (ITT) analyses, replacing missing outcome values by multiple imputation. Results: The prevalence of smoking increased from 5.8% at baseline to 17.0% at second follow-up among students at intervention schools, and from 7.6% to 18.7% among students at control schools. Analyses of available cases and ITT analyses did not support X:IT being effective in preventing smoking after the second year of intervention. Conclusions: Although X:IT was effective after the first year of intervention, we were not able to demonstrate any effects after the second year. Implementation of the intervention was lower in the second year compared to the first year which indicates that the missing effect of the intervention at second follow-up is due to lack of implementation.

Association of School Characteristics and Implementation in the X:IT Study-A School-Randomized Smoking Prevention Program

BACKGROUND

Assessment of implementation is essential for the evaluation of school-based preventive activities. Interventions are more easily implemented in schools if detailed instructional manuals, lesson plans, and materials are provided; however, implementation may also be affected by other factors than the intervention itself-for example, school-level characteristics, such as principal support and organizational capacity. We examined school-level characteristics of schools in groups of high, medium, and low implementation of a smoking prevention intervention.

METHODS

The X:IT study is a school-randomized trial testing a multicomponent intervention to prevent smoking among adolescents. Our data came from electronic questionnaires completed by school coordinators at 96.1% of participating intervention schools (N = 49) at first follow -up.

RESULTS

Schools that implemented the X:IT intervention to a medium or high degree had higher levels of administrative leadership (77.3% and 83.3% vs 42.9%), school climate/organizational health (95.5% and 91.7% vs 66.7%), mission-policy alignment (90.9% and 100.0% vs 71.4%), personnel expertise (81.8% and 75.0% vs 46.7%), school culture (77.3% and 91.7% vs 53.3%), positive classroom climate (91.4% and 96.2% vs 82.9%) compared with low implementation schools.

CONCLUSION

Our findings highlight the importance of considering the school context in future health prevention initiatives.

High impact of implementation on school-based smoking prevention: the X:IT study-a cluster-randomized smoking prevention trial

BACKGROUND

Implementation fidelity describes how well an intervention is implemented in the real-world setting. Assessing implementation fidelity is essential in the understanding of intervention results. In most studies, implementation fidelity is measured insufficiently, though, not taking into account the complexity of the concept nor the intervention. The objective of the present study was to develop an overall quantitative measure of implementation fidelity, to examine the degree of implementation fidelity and the association of implementation and effect of a randomized school-based smoking prevention trial-the X:IT study.

METHODS

A cluster-randomized trial testing is a multi-component intervention to prevent smoking among adolescents in 94 Danish elementary schools (51 intervention, 43 control schools). Participants were grade 7 pupils (mean age 12.5 years). Data was collected by electronic questionnaires among pupils at baseline (n = 4161), the first follow-up (n = 3764), and the second follow-up (n = 3269) and among school coordinators at intervention schools at the first and second follow-up (50 and 39 coordinators).

INTERVENTION

The intervention included three components: (1) smoke-free school grounds, (2) smoke-free curriculum, and (3) parental involvement, contracts, and dialogues. Implementation fidelity was assessed by four domains: adherence, dose, quality of delivery, and participant responsiveness. These were combined into an overall school-wise implementation index. The association of implementation and smoking was examined by logistic regression analyses.

RESULTS

One fourth of the schools was characterized as high implementers of the program (all three components) at both first (12 schools, 24.0 %) and second follow-up (11 schools, 28.2 %). Implementation fidelity was strongly associated with smoking at the first and second follow-up, e.g., the odds for smoking at schools with high implementation both years were OR = 0.44 (95 % CI 0.32 to 0.68).

CONCLUSIONS

Using an overall measure based on several aspects of implementation fidelity, we showed a negative graded association between implementation and smoking. This study suggests that higher degrees of implementation will improve the effect of the X:IT intervention. Studying the association between implementation and effect is extremely important; only by doing so, we can distinguish the quality of the intervention from the success of the implementation.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN77415416.