Title:BE SMART AGAINST CANCER! A school-based program concerning cancer-related risk behavior: a randomized controlled intervention study

Transcription

1 Author's response to reviews Title:BE SMART AGAINST CANCER! A school-based program concerning cancer-related risk behavior: a randomized controlled intervention study Authors: Friederike Stölzel (friederike.stoelzel@uniklinikum-dresden.de) Nadja Seidel (nadja.seidel@uniklinikum-dresden.de) Stefan Uhmann (stefan.uhmann@gmail.com) Michael Baumann (michael.baumann@uniklinikum-dresden.de) Hendrik Berth (hendrik.berth@uniklinikum-dresden.de) Jürgen Hoyer (hoyer@psychologie.tu-dresden.de) Gerhard Ehninger (gerhard.ehninger@uniklinikum-dresden.de) Version:7Date:27 January 2014 Author's response to reviews: see over

2 Universitäts KrebsCentrum Dresden UCC Direktorium: Prof. Dr. med. G. Ehninger (geschäftsführend) Prof. Dr. med. M. Baumann BMC Public Health Executive Editor Natalie Pafitis Dipl.-Psych. Nadja Seidel UCC-Prevention Center Tel.: nadja.seidel@uniklinikum-dresden.de Dresden, January 23 rd nd Revision of the Manuscript (ID: ) Be smart against cancer! A school-based program concerning cancer-related risk behavior: a randomized controlled intervention study Dear Executive Editor, dear Members of the Editorial board, dear Reviewers, thank you very much for your of January 3 rd 2014 related to our manuscript and for the fast and profound review process. We very much appreciate the latest opportunity to resubmit a revised version. Please find now attached the revised version for your kind consideration for publication in your renowned journal. We have modified the manuscript in accordance to the comments of the reviewers and hope that we have answered all open questions and were able to improve the understanding and the quality of the manuscript. Zertifiziert nach DIN EN ISO 9001:2008 Gemeinsame Einrichtung von: Medizinischer Fakultät Universitätsklinikum Carl Gustav Carus und Partnern gefördert durch: Thank you again for your kind consideration. Sincerely, Nadja Seidel and Friederike Stölzel University Cancer Center, University Hospital Carl Gustav Carus, Dresden University of Technology

3 Responses to Reviewer s report: Reviewer: David B Buller Version: 3 Date: 23 December 2013 Reviewer's report: This revised paper in which the authors report on an evaluation of a cancer prevention curriculum has been improved in several ways. In particular, the authors have revised their statistical analysis plan to use appropriate techniques to adjust for clustering of students within schools in their group-randomized design. Also, mediational analysis procedures have been improved since the prior submission. The authors now acknowledge the limitation of their short follow-up period. Major Compulsory Revisions Comment 1: The lack of mediation of intentions by the improved knowledge scores underscores the weaknesses of the apparent assumption that knowledge is a predictor of behavior. The authors do acknowledge this shortcoming in the discussion but they need to more clearly speculate on what other factors may have led to the curriculum being effective at increasing intentions and how the curriculum was designed to affect these other factors. Response: Thank very much for your important remark. We now speculate more precisely about other variables that may have influenced intentions, taking further theoretical models in consideration. Additionally, we describe how BSAC exercises may have affected these variables (e.g. self-efficacy), even if the curriculum was designed according to the Theory of Planned Behavior. Page 13: BSAC was also effective in raising health-promoting intentions. According to the Theory of Planned Behavior intentions for behavior change are influenced by socialcognitive determinants such as subjective norms, attitudes and perceived behavior control [36]. As described above, these were supposedly addressed by the intervention. Other possible determinants of intention-building are described by the Health Action Process Approach (HAPA) [37]. It claims outcome expectancies and task self-efficacy to play a crucial role in what people choose to do. Perceived risk may also stimulate intentions to adopt, initiate or maintain health behaviors. For Fischoff on the other hand, deciding to engage in health-promoting behavior depends on components as identifying alternative options and possible consequences [42]. All these variables may have been affected by the BSAC curriculum and some constructs might even overlap, for example perceived behavior control and self-efficacy. Thus, the role-play about sun-protection, designed to support perceived control and positive attitudes towards sun-protection, may also boost student s self-efficacy to perform the desired behavior or outcome expectancies towards the judgment of peers. The mediation analysis showed no mediating effect of knowledge on intention, thus strengthening the assumption of social-cognitive determinants as important prerequisites for intention-building. However, since social-cognitive determinants have not been assessed in the study, their mediating effect in fostering health-promoting intentions remains hypothetical. 2

4 Page 8: The BSAC curriculum is based on the Theory of Planned Behavior [36]. All components and exercises are therefore designed to foster subjective norms, attitudes and perceived control over their actions concerning the specific preventive behaviors. Teaching materials created by German Cancer Aid (Deutsche Krebshilfe e.v.) were enhanced by medical and educational experts working at the UCC. A variety of didactical methods as information, class discussion, role-play, quiz, pantomime, group-work and video clips was used affecting the social-cognitive prerequisites of intentions as well as the transmission of knowledge. Concerning sun-protection for instance, a class discussion about social norms (e.g. My friends think being sun-tanned is pretty and healthy ) and attitudes (e.g. I think sun-protection is important ) was conducted. A role-play supported perceived control over sun-protective behavior since practical training encourages the execution of actions. Students were informed about risks and use of the sun-light via a short video clip and tested the benefits of different sun-protective behaviors in consideration of the six skin types via an interactive computer animation. Table 2 specifies the topics and the didactical methods used within each module. The BSAC teaching team consisted of members of the UCC and was trained by a teaching-experienced member of the UCC-Cancer Awareness Group. A manual provides all necessary facts about cancer and related risk factors and describes the implementation of the curriculum. Comment 2: The authors spend a great deal of space in the discussion considering issues not related to trial outcomes. This content should be shortened and more space devoted to explaining how the curriculum may be effective at improving intentions and how it might actually translate into improved health behaviors. Response: Thank you very much for pointing out this shortcoming. We removed unrelated contents and discussed in detail how the curriculum may have affected intentions (see response to comment 1) and how intentions may improve health behavior. Page 13:Alcohol consumption was followed by unhealthy eating habits and insufficient physical activity. Considering these most frequently mentioned risk behaviors, the original module-classification should be critically evaluated. In order to adjust the BSAC curriculum, the module Sun protection could be complemented by Physical activity and the module Physical activity, Healthy nutrition and Limited alcohol consumption could be restricted to Healthy nutrition and Limited alcohol consumption. Especially the great number of students consuming alcohol on a rather regular basis is alarming considering the legal restriction of drinking alcohol at the age of 16 years at the earliest in Germany. Since it is recommendable to provide interventions before young people begin to experiment with risk behaviors [20, 21] raising awareness and knowledge about alcohol should be initiated earlier than in seventh grade. The rising overall risk-score with increasing age is another argument for early intervention as well as the fact that risk behaviors may become permanent and difficult to modify [9]. Page 14: Several theories of behavior (e.g. Health Action Process Approach [41]) assume a positive influence of perceived health risk on the intention to change health-related risk 3

5 behavior. A person at high risk should therefore have a higher intention to change behavior. Page 14: Good intentions cannot always be translated into corresponding actions, since various factors can be compromising [37]. As described in the HAPA-model, action planning, self-efficacy as well as situational determinants, e.g. barriers may play an important role. For adolescent smokers, intentions were found to predict planning. On the other hand, planning serves as a predictor for actual behavior. One possibility to foster self-efficacy and to overcome barriers in school settings might be the initiation of classlevel projects. A contest of projects with students working on a specific cancer related risk behavior such as smoking is currently conducted by the UCC Prevention Center. Minor Essential Revisions Comment 1: It would be useful to compare the individuals in schools that dropped out of the trial with those that remained in the trial on the risk, knowledge and intention scales, not just demographics, to be sure that the drop out did not create further biases. Response: Thank you very much for this comment. Further statistical analyses showed no biases regarding outcome variables at baseline. Page 6: These remaining 235 students (IG and CG) did not differ from students (N=401) excluded from analysis (IG and CG) regarding risk-score (t(622)=0.97, p=.33), knowledge-score (t(634)=0.002, p=.998), intention-score (t(624)=0.19, p=.85) at baseline and age (t(629)=- 0.46, p=.64), but regarding gender (included: 59% male, excluded: 48% male; χ²(1)=7.87, p=.01). Comment 2: The risk scale still suffers from a basement effect. At the very least, this limitation needs to be acknowledged in the discussion Response: Thank you for pointing out the assessment of the risk behavior. The low values of the risk score reflect the small number of students that were engaged in risk behavior. We now added the basement effect to the limitations and discussed implications for the BSAC-program in the discussion section. Page 14: However, only few students in this study were engaged in risk behaviors, thus limiting the power of the program to reduce risk behaviors. The BSAC-program might therefore be successful at maintaining sufficient health behaviors rather than improving inadequate behaviors. Page16: The risk scale might suffer from a basement effect and knowledge and intention scales at post-test might show ceiling effects. Comment 3: The internal consistency of the risk scale and the knowledge scale are very low. The authors should consider analyzing these outcomes separately Response: Thank you very much for your remark. Risk scale and knowledge scale contain diverse items, explaining the low internal consistency. The 4

6 knowledge score reflects the contents of the BSAC curriculum. A factor analysis did not result in any reasonable subscales. Knowledge about cancer therefore seems not to be a homogenous construct. However, for a better understanding we decided to build a summary score instead of analyzing single items. The composite score of risk behaviors enables to compare students showing a very limited risk behavior to those at higher risk. To improve transparency regarding the risk-score, we registered the frequency of each risk behavior separately (Table 4). Comment 4: The authors still need to provide a more extensive description of how the curriculum was designed to influence health risk behaviors. Response: Thank you for your comment. By way of the sun-protection module, we now described in detail how the curriculum was designed and how it might influence risk behaviors. Page 8: The BSAC curriculum is based on the Theory of Planned Behavior [36]. All components and exercises are therefore designed to foster subjective norms, attitudes and perceived control over their actions concerning the specific preventive behaviors. Teaching materials created by German Cancer Aid (Deutsche Krebshilfe e.v.) were enhanced by medical and educational experts working at the UCC. A variety of didactical methods as information, class discussion, role-play, quiz, pantomime, group-work and video clips was used affecting the social-cognitive prerequisites of intentions as well as the transmission of knowledge. Concerning sun-protection for instance, a class discussion about social norms (e.g. My friends think being sun-tanned is pretty and healthy ) and attitudes (e.g. I think sun-protection is important ) was conducted. A role-play supported perceived control over sun-protective behavior since practical training encourages the execution of actions. Students were informed about risks and use of the sun-light via a short video clip and tested the benefits of different sun-protective behaviors in consideration of the six skin types via an interactive computer animation. Table 2 specifies the topics and the didactical methods used within each module. The BSAC teaching team consisted of members of the UCC and was trained by a teaching-experienced member of the UCC-Cancer Awareness Group. A manual provides all necessary facts about cancer and related risk factors and describes the implementation of the curriculum. Quality of written English: Needs some language corrections before being published. Language has been improved. 5

7 Reviewer:Ozum ERKIN BALYACI Version:3Date:15 December 2013 Reviewer's report: No Revision needs All suggestions (at first round) were done. Level of interest: An article whose findings are important to those with closely related research interests Quality of written English: Acceptable Statistical review: No, the manuscript does not need to be seen by a statistician. Declaration of competing interests: I declare that I have no competing interests. 6