Most studies addressing smoking cessation using social psychological frameworks like the TPB have neglected the fact that different processes might guide various target groups, e.g. in their attempts to quit smoking. Examining potential moderating effects enables us to detect under which conditions the model is suitable for predicting intention and behaviour, and under which conditions it is not.
Since no previous studies dealing with smoking cessation have addressed age and /or gender differences, the predictive utility of the TPB in different age and gender groups was examined (Paper 1). In Paper 2, past behaviour in terms of previous quit attempts was employed as a moderator of the TPB components. By examining the predictors of smoking cessation and potential moderator effects in various subgroups of the population, one can also obtain information that is crucial for designing tailored interventions.
Paper 1 and 2 in this thesis are based on the assumption that the motivation to quit smoking is explained by the determinants specified in the TPB. According to this theory, motivation is of vital importance for behavioural performance and is assumed to result from the following predictor variables: (i) attitude, (ii) subjective norm, and (iii) perceived behavioural control.
In Paper 1 it was hypothesized that the extension variables descriptive norm, moral norm and previous quit attempts would increase the predictive utility of the TPB model in order to predict intention to quit smoking and smoking cessation. Age (15-19 versus 35-55 years) and gender were used as moderators in the study. In Paper 2 it was assumed that the extension variables self identity as a smoker, group identity, moral norm and past behaviour would increase the predictive utility of the model in predicting intention to quit smoking. Past behaviour in terms of past quit attempts was used as a moderator.
Paper 3 deals with nursing students’ smoking behaviour and attitude towards smoking during their education programme. Existing research provides inconclusive results concerning the smoking rate during the nursing education and little is known of how attitude towards smoking change during the education period. Thus, in Paper 3, the stability of smoking behaviour and attitudes towards smoking and the relationship between attitudes and behaviours was examined. In addition, whether smoking was related to previous experience as a health care worker was explored.
In Paper 1, data was collected in 2005/2006 from a prospective sample of 447 daily smokers (adolescents, 16-19 years, n= 174, m=17.5 years; adults 35-55 years, n=311, m= 44 years). The extended TPB model was suitable to explain the intention to quit in both age groups; R2= .44 for adolescents and R2= .50 for adults (Paper 1). In predicting subsequent smoking cessation, the model did a better job among adults (R2= .29) than among adolescents (R2= .17). Two significant age group differences were revealed, i.e., intention was a significantly stronger predictor of behaviour among adults than among adolescents. Moreover, the interaction term PBC X intention was a significantly stronger predictor of behaviour among adolescents than among adults.
In Paper 2, data was collected in 2002 among 357 daily smokers (students, mean=24 years). The results showed that the extended TPB model was far better suited to predict the intention to quit smoking among daily smokers with experience from previous quit attempts (R2= .28) compared with those without previous attempts (R2= .01). PBC and group commitment were significantly stronger predictors of intention among those who had several previous quit attempts compared with those who never had tried quitting. The results in Paper 1 and 2 indicate that in order to motivate people to quit smoking efforts should be directed towards strengthening the perceived control over behaviour, e.g. by setting and achieving sub-goals. It might also be useful to focus on moral norm, e.g. responsibility for one’s own health condition in an investigation aimed at strengthening the intention to quit smoking. Concerning daily smokers with previous quit attempts, such efforts should be focusing on the consequences of quitting and perceived control over quitting smoking. This might e.g. imply increasing emphasis on the health profit of quitting smoking in campaigns and among health practitioners. To strengthen the identification with the group of non-smokers and their norms may also be important.
Data in Paper 3 was collected from a longitudinal sample of 382 Norwegian nursing students (2002-2005/ m=27.8 years, range 18-55 years). Nursing students had approximately twice the daily smoking rate of a student sample at the University of Oslo (nearly 30% versus nearly 10%, respectively). This smoking pattern did, however, correspond with the gap between students and others of the same age, suggesting that there is a social gradient in the smoking pattern. Even if the smoking frequency declined significantly from T1 to T2, (45.8% versus 36.4%), the high smoking rate may constitute a serious obstacle to the recruitment of nurses to tobacco smoking effort. Nevertheless the findings that attitude predicted behaviour directly both at T1 & T2 supported the need for an attitude campaign as part of programmes