Cigarette smoking continues to be a serious problem with detrimental health consequences for the individual and tremendous costs for society . In the Netherlands, the smoking prevalence rate is high, with 27.7% of the population above 15 years smoking . A substantial part of Dutch adult smokers intend to quit smoking in the future [2, 3]. Unfortunately, most quit attempts fail, and approximately three-quarters of unaided quitters resume smoking within three months .
Several intervention programs have been shown effective in increasing the chance of successful smoking cessation. However, only a minority of smokers makes use of such programs [5, 6]. A possible explanation for this low rate may be that most programs rely on the smoker to take the initiative . Proactive recruitment approaches to smoking cessation are scarce, even though such approaches may greatly enhance use of cessation support and, in turn, successful smoking cessation.
In the present study, smoking parents will be proactively recruited through their children's primary schools to participate in a randomized controlled trial evaluating the effectiveness of telephone counselling to aid smoking cessation. Telephone counselling has previously been shown to be effective in increasing smoking cessation rates in a meta-analytic review . A recent Australian study utilized a proactive recruitment approach to increase smokers' use of telephone cessation support. In this study, 52% of identified smokers from a randomly called sample of 48,014 households agreed to participate in a randomized controlled trial to evaluate the effectiveness of telephone counselling in smoking cessation. Participants receiving telephone counselling were significantly more likely to report 7-day point prevalence abstinence at the 4-month (13.8% versus 9.6%) and 7-month assessment (14.3% versus 11%) compared to participants in the control condition . As demonstrated in this study, proactive recruitment into telephone counselling seems an efficient way to increase use of cessation support and to enhance rates of smoking cessation in the general population.
In addition to the direct health benefits for smokers, smoking cessation of parents may have incremental effects for their children. Smoking behaviour of parents is an important risk factor for smoking initiation and smoking behaviour of children. A recent meta-analysis concluded that smoking behaviour of one parent significantly increases the child's risk to initiate smoking, and smoking behaviour of both parents adds to this risk . As nicotine is severely addictive, experimentation with and uptake of smoking is hazardous behaviour. Prevention of children's exposure to factors that increase their risk of smoking initiation constitutes a significant task in tobacco control.
The effects of parental smoking on child smoking are likely to be mediated by children's smoking-related cognitions (e.g., attitudes towards smoking, normative beliefs about smoking, risk and benefit perceptions, tobacco refusal self-efficacy, intention to smoke). Previous research has shown that children of smoking parents are more likely to have more tolerant and positive attitudes towards smoking [11, 12], more normative perceptions of smoking , and a stronger intention to smoke . Smoking-related cognitions, in turn, have been established as prospective predictors of smoking initiation in adolescents [14, 15].
Parental smoking cessation, however, has been shown to constitute an efficient way to decrease children's risk of smoking initiation . The shorter the exposure to family models who smoke, the less likely it is that children will initiate smoking themselves . The effect of parental smoking cessation has been shown to be mediated by their children's cognitions. In a recent study, 49% of the prospective relationship between parental smoking cessation and smoking behaviour of children was significantly mediated by negative attitudes toward smoking and tobacco refusal self-efficacy . Presumably, telephone counseling to aid parental smoking cessation may have measureable effects in children of smoking parents as well.
Aim and hypotheses
The primary aim of this study is to conduct a 2-arm randomized controlled trial to evaluate the effectiveness of proactive telephone counselling in increasing cessation rates among smoking parents. In addition, we will evaluate differences in smoking-related cognitions among children of parents in the telephone counselling and in the control condition. Three assessments among parents and children will take place (baseline, three months after start of the intervention, and twelve months after start of the intervention). Primarily, we expect higher smoking cessation rates among parents in the telephone counselling condition than in the control condition. Also, we expect children of parents in the telephone counselling condition to have more negative attitudes towards smoking, less normative perceptions of smoking, higher self-effectiveness to refrain from smoking, and a lower intention to start smoking than will children of parents in the control condition.