Iris Kanera

128 Chapter 5 Smoking behavior No significant intervention effects have been found for smoking behavior after six months. However, the likelihood of giving up smoking was almost three times higher in the IC than in the UC ( OR = 2.89). Nonetheless, this has to be interpreted with caution due to the limited amount of smokers in our study population. With higher numbers of smokers and the possibility to apply multilevel logistic regression analysis, it could be expected that significant results might occur in favor of the IC. Multiple behavior interventions This multiple behavior KNW intervention was especially designed to cover a broad range of relevant topics to meet the various cancer survivors’ needs (Kanera et al., 2016a; Willems et al., 2016). Besides targeting PA, diet, and smoking, the KNW also offered modules targeting fatigue, anxiety and depression, relational problems, return to work, and residual problems. The lifestyle modules included less separate sessions as compared to other multiple health behavior change interventions for cancer survivors (Bantum et al., 2014; Goode et al., 2015; Green, Hayman, & Cooley, 2015). This could be a possible reason for the limited effects of the KNW on lifestyle. Moreover, it might have been difficult for cancer survivors to focus on numerous topics. Most of the participants visited two modules, and possibly, for some of the participants the psychosocial topics had a higher priority. Earlier research revealed that in the first year after cancer treatment, residual and psychosocial problems might impede lifestyle change (Bluethmann et al., 2015). Furthermore, within the KNW, the number of recommendations to follow a certain module varied individually with a broad range from zero to eight. This was dependent on the responses given at baseline. Wilson et al. (2015) described that intervention effects might be curvilinear related to the number of recommendations given, with a moderate number of recommendations being most beneficial among the general population. Limitations This RCT provided insightful and valuable findings despite the limited effects on lifestyle behaviors. Nevertheless, some limitations should be acknowledged. Regarding generalizability, the KNW participants were mainly middle-aged breast cancer survivors with an (above) average income level, and with little comorbidity. This might be too selective to represent the general cancer survivor population. However, these findings are in line with the prevalence of breast cancer in the Netherlands (Comprehensive Cancer Centre the Nederlands, 2011b), and with Kohl et al. (2013), confirming a higher reach of web-based interventions among female participants with higher socioeconomic status. Furthermore, the intervention tested is an eHealth intervention and participation demanded