Carl Griffin

Cluster randomised controlled trial of expert system based on the transtheoretical (“stages of change”) model for smoking prevention and cessation in schools

Abstract Objectives: To examine whether a year long programme based on the transtheoretical model of behaviour change, incorporating three sessions using an expert system computer program and three class lessons, could reduce the prevalence of teenage smoking. Design: Cluster randomised trial comparing the intervention to a control group exposed only to health education as part of the English national curriculum. Setting: 52 schools in the West Midlands region. Participants: 8352 students in year 9 (age 13-14 years) at those schools. Main outcome measures: Prevalence of teenage smoking 12 months after the start of the intervention. Results: Of the 8352 students recruited, 7444 (89.1%) were followed up at 12 months. The intention to treat odds ratio for smoking in the intervention group relative to control was 1.08 (95% confidence interval 0.89 to 1.33). Sensitivity analysis for loss to follow up and adjustment for potential confounders did not alter these findings. Conclusions: The smoking prevention and cessation intervention based on the transtheoretical model, as delivered in this trial, is ineffective in schoolchildren aged 13-14. Key messages The transtheoretical model proposes that individuals move through a series of stages in behaviour change A computer programme gave 13 and 14 year old school students tailored information about what stage they were in and what to do to move to the next stage Students given this information were no more likely to move stage, refrain from smoking, or stop smoking than those exposed to ordinary classroom health education There is no evidence that the computerised expert system based on the transtheoretical model is effective in smoking prevention and cessation

The importance of social sources of cigarettes to school students

Objective: To discover the importance of social sources of tobacco to young people as opposed to commercial sources; to describe the peer market for cigarettes in schools and the consequences for young people of their involvement in it. Study design: Cross sectional questionnaire survey, one-to-one interviews, and focus groups. Setting: Seven schools in Birmingham, UK. Subjects: All students in two randomly selected classes from each school completed the questionnaire, and never smokers, occasional smokers, and regular smokers were interviewed. Results: Two thirds of occasional smokers and one quarter of regular smokers obtained cigarettes socially, mostly for free. A few smokers regularly bought their cigarettes from others. Among friendship groups, both smokers and non-smokers were involved in the exchange of cigarettes, often for money, which is a common activity. A few young people use the selling of cigarettes to fund their own smoking. Some young people, smokers and non-smokers, are involved in semi-commercial selling of cigarettes. All school students are aware of where to purchase cigarettes from non-friends, which is only used “in emergency” because of the high price. One school had a strong punishment policy for students caught with cigarettes. In this school, more people bought singles from the peer market and the price was higher. Conclusions: The passing and selling of cigarettes in school is a common activity, which from the young persons perspective, ensures that all share cross counter purchases. A few people are prepared to use the peer market for monetary gain and it appears to be responsive to external conditions. The peer market might mean that efforts to control illegal sales of cigarettes are not as effective as hoped.

The effect of Transtheoretical Model based interventions on smoking cessation

The Transtheoretical Model (TTM) proposes that stage matching improves the effectiveness of behaviour change interventions, such as for smoking cessation. It also proposes that standard smoking cessation interventions are matched to the relatively few smokers in the preparation stage and will not assist the majority of smokers, who are in the precontemplation or contemplation stages. This study tested the hypothesis that stage-matched interventions increase movement through the stages relative to interventions not stage-matched. It also tested the hypothesis that the relative effectiveness of stage-matched interventions is greater for people in precontemplation or contemplation (stage-matched for TTM but not for control) than for people in preparation (where both intervention and control were stage-matched). A total of 2471 UK adult smokers were randomised to either control or TTM-based self-help intervention and followed up 12 months after beginning the programme. Content analysis of the intervention and control self-help interventions examined whether control interventions were action-oriented, meaning they emphasised the processes of change relevant for preparation and action. Participants in the TTM arm were slightly more likely to make a positive move in stage, but this was not significant. There was no evidence that the TTM-based intervention was more effective for participants in precontemplation or contemplation than for participants in preparation. There was no evidence that TTM-based interventions were effective in this trial. The control intervention advocated process use appropriate for all stages and was not action-orientated. Stage matching does not explain the modest effects of TTM-based interventions over control interventions observed in some trials. These effects may instead have occurred because TTM-based interventions were more intensive than control interventions.

A randomized controlled trial of smoking cessation for pregnant women to test the effect of a transtheoretical model-based intervention on movement in stage and interaction with baseline stage

OBJECTIVES To examine whether, as predicted by the transtheoretical model (TTM), stage-matched interventions will be more effective than stage-mismatched interventions. DESIGN Randomized controlled trial of smoking cessation advice to pregnant smokers. METHODS Pregnant women currently smoking at 12 weeks gestation were enrolled in a pragmatic three-arm trial of TTM-based interventions to help them stop smoking. One arm constituted standard midwifery advice and a self-help leaflet on stopping smoking, which is generally appropriate for women in preparation. Two arms were TTM-based. Differences in positive movement in stage towards quitting from enrolment to 30 weeks gestation and 10 days post-partum were calculated for each arm of the trial. We then examined whether, as predicted from the TTM, the relative benefit of the TTM-based intervention was greater for women in precontemplation and contemplation, for whom the control intervention was stage-mismatched, than for women in preparation, for whom the control intervention was stage-matched. RESULTS Women in the TTM-based arms were statistically significantly more likely to move forward in stage than were women in the control arm. Contrary to the TTM-derived hypothesis, the greater relative benefit of the TTM-based intervention was seen for women in preparation stage at baseline, rather than women in precontemplation and contemplation. CONCLUSIONS The TTM-based intervention was more effective in stage movement, but this could be due to its greater intensity. The failure to confirm that stage-matching was important casts doubt on the validity of the TTM in explaining smoking cessation behaviour in pregnancy.

What factors predict differences in infant and perinatal mortality in primary care trusts in England? A prognostic model

Objective To identify predictors of perinatal and infant mortality variations between primary care trusts (PCTs) and identify outlier trusts where outcomes were worse than expected. Design Prognostic multivariable mixed models attempting to explain observed variability between PCTs in perinatal and infant mortality. We used these predictive models to identify PCTs with higher than expected rates of either outcome. Setting All primary care trusts in England. Population For each PCT, data on the number of infant and perinatal deaths, ethnicity, deprivation, maternal age, PCT spending on maternal services, and “Spearhead” status. Main outcome measures Rates of perinatal and infant mortality across PCTs. Results The final models for infant mortality and perinatal mortality included measures of deprivation, ethnicity, and maternal age. The final model for infant mortality explained 70% of the observed heterogeneity in outcome between PCTs. The final model for perinatal mortality explained 80.5% of the between-PCT heterogeneity. PCT spending on maternal services did not explain differences in observed events. Two PCTs had higher than expected rates of perinatal mortality. Conclusions Social deprivation, ethnicity, and maternal age are important predictors of infant and perinatal mortality. Spearhead PCTs are performing in line with expectations given their levels of deprivation, ethnicity, and maternal age. Higher spending on maternity services using the current configuration of services may not reduce rates of infant and perinatal mortality.

A multi-component stair climbing promotional campaign targeting calorific expenditure for worksites; a quasi-experimental study testing effects on behaviour, attitude and intention

BackgroundAccumulation of lifestyle physical activity is a current aim of health promotion, with increased stair climbing one public health target. While the workplace provides an opportunity for regular stair climbing, evidence for effectiveness of point-of-choice interventions is equivocal. This paper reports a new approach to worksite interventions, aimed at changing attitudes and, hence, behaviour.MethodsPre-testing of calorific expenditure messages used structured interviews with members of the public (n = 300). Effects of multi-component campaigns on stair climbing were tested with quasi-experimental, interrupted time-series designs. In one worksite, a main campaign poster outlining the amount of calorific expenditure obtainable from stair climbing and a conventional point-of-choice prompt were used (Poster alone site). In a second worksite, additional messages in the stairwell about calorific expenditure reinforced the main campaign (Poster + Stairwell messages site). The outcome variables were automated observations of stair and lift ascent (28,854) and descent (29,352) at baseline and for three weeks after the intervention was installed. Post-intervention questionnaires for employees at the worksites assessed responses to the campaign (n = 253). Analyses employed Analysis of Variance with follow-up Bonferroni t-tests (message pre-testing), logistic regression of stair ascent and descent (campaign testing), and Bonferroni t-tests and multiple regression (follow-up questionnaire).ResultsPre-testing of messages based on calorific expenditure suggested they could motivate stair climbing if believed. The new campaign increased stair climbing, with greater effects at the Poster + Stairwell messages site (OR = 1.52, 95% CI = 1.40-1.66) than Posters alone (OR = 1.24, 95% CI = 1.15-1.34). Follow-up revealed higher agreement with two statements about calorific outcomes of stair climbing in the site where they were installed in the stairwell, suggesting more positive attitudes resulted from the intervention. Future intentions for stair use were predicted by motivation by the campaign and beliefs that stair climbing would help weight control.ConclusionsMulti-component campaigns that target attitudes and intentions may substantially increase stair climbing at work.