This present analysis sought to investigate the role of two psychosocial variables (dual hazard and decisional balance), informed by the social contextual framework, which were the main targets of the MassBUILT smoking cessation intervention. As we hypothesized, high levels of both variables were associated with smoking cessation. However, although both were explicitly targeted by the intervention, we found that the intervention did not change decisional balance and it decreased, instead of increased, the apprentices’ perception of risk from dual hazard. Further analysis revealed that the effect on dual hazard was primarily due to the effect that the intervention had on the apprentices’ perception of risk from smoking, which is that as a result of the intervention, the apprentices perceived smoking to be more hazardous. The study results reveal that the hypothesized mediators did not play a role in smoking cessation among the MassBUILT cohort.
It is important to consider some limitations to our study prior to discussing possible implications of our results. We relied on self report for measurement of the outcome and predictors and could not implement biochemical or respiratory verification of smoking status in this study. The need for validation of smoking cessation in population based studies has been questioned (Murray, Connett, Istvan, Nides, & Rempel-Rossum, 2002
; Velicer et al., 1995
). Also, the variables involve psychosocial processes that are only feasible to collect as self-report. We made sure that all variables were collected using the same method at all study periods and used validated scales where available. Contamination of the intervention was possible in our study because it was possible that the apprentices, while separated in the study by control and intervention training sites, worked together at the same worksites. We expect that such contamination, if it occurred, would attenuate the overall effects of the intervention but would not change the ability to assess the mediators through which the intervention was effective. Lastly, the results of the study suggest that there were other mediators through which the intervention had its effect and it is likely that these mediators were not assessed in the study. We considered response burden in the design of our survey and chose to only collect information on mediators based on a priori
The strengths of our study include our prospective and group randomized controlled design. This study design allowed us to examine longitudinal changes in the mediators and to compare the pre and post intervention changes to a control group that did not get the intervention. Without this comparison, we would not have known that the changes in the psychosocial variables were not significant. Both variables significantly changed pre and post intervention but the changes were not significantly different between the intervention and control groups. The group randomized design of the study increased the internal validity of the study and decreased selection bias because sites were randomly assigned to treatment group. Therefore, sites with apprentices who were more or less motivated to quit smoking were equally distributed across intervention and control groups.
Implications for Practice
Our study has several implications for current work on smoking cessation among blue-collar workers. Other mediation analyses of multi-component interventions have produced similar results where the intervention was effective but the hypothesized mediators were not found to be mediators of the effect (Calfas, Sallis, Oldenburg, & Ffrench, 1997
; Haerens, Cerin, Deforche, Maes, & De Bourdeaudhuij, 2007
; Lubans & Sylva, 2007
). It is possible that the intervention, as a multi-component unit, had a direct effect on smoking cessation. In that case, the various components of our intervention worked synergistically to facilitate smoking cessation among the apprentices in the intervention group and their effects cannot be decomposed. On the other hand, it is possible that there are other factors that actually did fully or partially mediate the effects of the intervention. The fact that these factors were not our hypothesized mediators and thus not the focus of the intervention, could have contributed to the smoking relapse that we found at time 3.
Another important implication of our study is that it supported the theoretical basis of our intervention even as it revealed that the intervention did not achieve one of its main objectives. Using the social contextual model and formative work from the pilot study, we diagnosed that an understanding of the dual hazard from occupational hazard and smoking will lead to an increase in smoking cessation. Our results show that high scores on this concept were associated with improved smoking cessation. In fact, a one point increase in the variable was associated with double the rate of smoking cessation, regardless of intervention group. We cannot credit our study with increasing this awareness but other studies can use this information in designing smoking cessation interventions for blue-collar workers.
The main message of dual hazard is that smoking works synergistically with occupational hazard to decrease health. Our study did not succeed in driving this message home. However, we significantly increased the perception of smoking as hazardous to health among those in the intervention group. That this generic message, which the apprentices possibly get through other sources including the warning labels on cigarette packs, had such an impact on the apprentices point to a possibility that smoking was not viewed negatively among the apprentices at baseline. The high prevalence of smoking in this population along with the finding that we did not change the apprentices’ perception regarding the benefits and barrier to smoking, warrant an examination of what drives smoking behaviors in this population. It is possible that there is a need to expand on the model used in the intervention and not just hone in on the work-related aspects of smoking behavior. We recommend that future interventions devote more time before implementation of the intervention to formative research using both qualitative and quantitative methods. Through formative research, interventionist can understand how smoking is viewed and experienced by the apprentices. In addition, formative research could help interventionists understand what the smokers in the study believe would have helped them quit and what in their environment would need to be changed to encourage prolonged smoking cessation.
Interventions to improve smoking cessation among blue-collar populations have produced mixed results and many have been unsuccessful (Campbell et al., 2002
; Moher et al., 2005
; Sorensen et al., 2004
; Willemsen et al., 1998
). The MassBUILT intervention was successful; however, the effects of the intervention did not last beyond six months. The test of mediation showed that the intervention did not significantly change smoking decisional balance among the apprentices. Smoking decisional balance captures a weight of how people see the barriers versus benefits of smoking. That the study did not impact how the apprentices weigh the barriers versus benefits of smoking could have contributed to the significant relapse at the end of the study.
The perceived benefits evaluated by the decisional balance scale include smoking’s ability to relieve tension, improve concentration and induce relaxation while the barriers were embarrassment at smoking, concern about smoke from cigarette bothering other people and feeling foolish for ignoring warnings about harm of smoking. Our intervention did not change how the apprentices view these benefits and barriers. Future interventions could include more interactive sessions to address the possibility of an entrenched view of smoking as beneficial in a setting such as this where 40% of the participants were current smokers and 61% smoked in the last 30 days. For example, the Toxics and Tobacco curriculum could have been modified to start with a group discussion of smoking. This session would involve both smokers and non-smokers and could include an evaluation of the benefits and barriers of smoking as perceived by the apprentices. In addition, given the evidence of a dose-response relationship between number of smoking cessation sessions and smoking cessation (Fiore et al., 2008
), the number of group sessions in the intervention could have been increased to include more class time for discussion of the benefits and barriers to smoking.
In conclusion, our study underscores the importance of examining the how interventions affect psychosocial variables through which the interventions are supposed to operate. The significant smoking relapse in our intervention could have been interpreted to indicate a failure of the theoretical basis of our intervention. However, our analysis show that the psychosocial variables were important to smoking cessation but our intervention did not have the desired effects on these variables. Few studies exist on psychosocial correlates of smoking cessation in worksite interventions with which to compare our results. Further studies are needed to test mediators of worksite based smoking cessation intervention because even negative findings can help interventionists understand what variables are related to smoking cessation and if the different components of the worksite intervention can be decomposed.