Health Education Research, Vol. 18, No. 1, 88-97,
February 2003
© 2003 Oxford University Press
‘You and Your Skin’: a short-duration presentation of skin cancer prevention for teenagers
Stockholm Center of Public Health and Department of Oncology–Pathology, Karolinska Institute, 171 76 Stockholm,1 Department of General Oncology, Karolinska Hospital, 171 76 Stockholm and2 Saltsjöbadens Samskola, Samskolavägen 1, 133 34 Saltsjöbaden, Sweden.
Correspondence to: S. Kristjánsson, Department of Cancer Prevention, Karolinska Hospital, M8, 171 76 Stockholm, Sweden
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Abstract |
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The effectiveness of a short-duration presentation of the educational material ‘You and Your Skin’ was tested on 184 adolescents (age 13–15) at the Year 7 and 8 levels. A non-equivalent control group design was used with pre-testing and post-testing 3 months after the intervention. The intervention increased the students’ knowledge of known risks factors for skin cancers. However, the students’ attitudes to abstaining from sunbathing and tanning was not significantly affected. The effect of the intervention on the stage of change was primarily a progression from the precontemplation stage to the contemplation stage regarding avoiding the mid-day sun. We conclude that a brief presentation of the educational kit ‘You and Your Skin’ can be used to increase knowledge, but there is a need for a more extensive intervention effort to affect students’ readiness to change their behavior and attitude towards sunbathing and tanning. Therefore, it is important to emphasize the necessity of using the educational kit as a multi-lesson programme with its several group exercises.
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Introduction |
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The incidence of melanoma and non-melanoma skin cancers has increased rapidly in Sweden during the last 20 years (National Board of Health and Welfare, 1999
). There is an increase in mortality from malignant melanoma for both genders in most countries of the European Community (Balzi et al., 1997).
Evidence from epidemiological studies supported by laboratory work has led to a consensus in the scientific community that sun exposure is the main environmental factor in the etiology of malignant melanoma (Stierner et al., 1988; Elwood and Jopson, 1997). Other known risk factors are poor tanning ability, melanoma in the family, the number of dysplastic nevi and a history of non-melanoma skin cancer (Holman et al., 1986). It has been estimated that 80% of all skin cancers are caused by ultraviolet radiation (UVR) from the sun and prevention should therefore be a viable route to reduce the incidence (Armstrong and Kricker, 1993).
Epidemiological evidence and behavioral factors highlight childhood and early adolescence as an important period for skin cancer prevention (Weinstock et al., 1989). A high level of sun exposure in childhood is a strong determinant of melanoma risk in adulthood (Whiteman et al., 2001). Sun-protection behavior adopted early in life may have an effect on the risk of developing skin cancer later in life. A recent Swedish survey showed that the frequency of sunbathing and artificial sunbed use was high in the studied population (13–17 years), and increased with age from 33 to 52% for sunbathing and from 1 to 19% for sunbed use (Brandberg et al., 1998).
Schools have a great potential for reaching and educating teenagers about skin cancer prevention. A short presentation programmes can be easily included in the curricula for various subjects, e.g. science, health and physical education, and is therefore a valuable tool for increasing awareness of skin cancer risks, and altering attitudes to sunbathing and tanning. Most evaluations of school-based skin cancer prevention programmes, using experimental or quasi-experimental designs, have involved pre-adolescents. These studies often demonstrate an increased knowledge of skin cancer prevention, and, in some cases, changes in attitudes and sun-protection behavior (Buller and Borland, 1999).
There are few reported school-based studies involving adolescents (Buller and Borland, 1998). One study using one-session intervention presentations for Year 9 and 10 students showed an increase in the students’ knowledge of skin cancer, but no effect on intention to change behavior (Mermelstein and Riesenberg, 1992). Another brief intervention study among English teenagers (age 12–16) reported that the intervention groups had better knowledge and more favorable attitudes at post-test compared with a control group. However, there was no difference in reported sun-protection behavior between the groups (Hughes et al., 1993).
The Transtheoretical Model (TTM) is a general model of behavior change that has been increasingly applied in health promotion and prevention of diseases, e.g. smoking cessation, exercise adoption and condom use, and can also be used for sun-related behavior (Prochaska et al., 1994a; Rossi et al., 1995; Weinstock and Rossi, 1998). One of its central components is the stage of change. It is postulated that people move through five discrete stages, from precontemplation to maintenance, when changing behavior (Prochaska and DiClemente, 1983). Other important components of the model are processes of change, decisional balance (weighing pros and cons) and self-efficacy (Prochaska and Velicer, 1997). The TTM has been adapted to research and to development of interventions to change several behaviors, including sun-related behavior (Prochaska et al., 1994b; Weinstock and Rossi, 1998; Nigg et al., 1999). In present study, the stage of change assessment is used to measure the effect of the intervention.
The purpose of this study was to evaluate the effectiveness of a school-based intervention programme using the skin cancer prevention kit ‘You and Your Skin’. The intervention was presented in one session (45 min) to students at the Year 7 and 8 levels in lower secondary schools. Our hypothesis was that the intervention group would show a greater increase between the pre-test and the post-test evaluations than the control group in the following categories: (1) knowledge of the risk factors for skin cancer, UVR exposure and sun-protection behaviors, (2) attitude towards sunbathing and tanning, and, finally, (3) the intervention was expected to raise the students’ consciousness of skin cancer risks which would lead to a progression in the stages of change (Rosen, 2000). Thus, there would be a larger number of students in the intervention group who have progressed in their readiness to change sunprotection behaviors than in the control group.
To our knowledge, the present study constitutes the only evaluation of educational material for skin cancer prevention among teenagers in which the school staff implemented the intervention using a quasi-experimental design with pre-testing and post-testing. This is also the first study that uses the stages of change concept, modified from the TTM, to assess the effects of a school-based skin cancer prevention presentation on readiness to change sun-protection behaviors.
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Methods |
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Development of the educational material
In cooperation with the Swedish Radiation Protection Institute, the Department of Cancer Prevention initiated the development of an educational kit for skin cancer prevention among lower secondary school students. The material was developed in 1996 in close collaboration with teachers and students in a school not participating in the evaluation study. We asked 130 students (age 13–15) to write an essay on sun and tanning-related themes, and subsequently processed these essays in a focus group discussion. The Health Belief Model was used as a theoretical framework in the development of the intervention (Janz and Becker, 1984
). At the suggestion of the students and teachers the intervention emphasized positive messages using humor to capture the attention of the students, and material that might upset them (fear propaganda) was avoided. Sun-protection behaviors, such as staying in the shade, avoiding the sun between 11 a.m. and 3 p.m., using clothes to block exposure to the sun, applying a sunscreen with a sun-protection factor of 15 or higher to exposed skin, and avoiding artificial sunbeds, were highlighted. Additionally, the kit provided facts about the causes and consequences of UVR overexposure and skin cancer. The educational kit was then constructed and its appropriateness, i.e. whether it was feasible to go through all parts of the material, and leave some time for discussion and questions, was assessed. Furthermore, after distribution of the kit to various schools, an independent marketing study revealed that 94% of the teachers were satisfied with the kit and thought it was suitable for this age group.
Design and recruitment
Four municipalities in Stockholm County were selected on the basis of size and socioeconomic status. Public health officers in these municipalities were contacted and they helped in the selection of schools. Five non-private schools in the municipalities were selected with respect to their interest in participating in the study. Two interventions and two control classes were selected in each municipality. In one municipality, there were two schools, which supplied two classes each. In every school there were an equal number of classes randomly assigned to intervention and control. One teacher/nurse from each school was responsible for conducting the study and collecting data.
The design was that of a non-equivalent control group with pre-testing and a post-testing. Eight Year 7 year classes (age 13–14) and eight Year 8 classes (age 14–15) completed the pre-test, and 1 week later the educational kit was implemented in four Year 8 classes and four Year 7 classes. Each student was given an identification number before the pre-test to allow analysis at the individual level. Three months after the intervention, the post-test was given to both the intervention and the control classes. The teachers who were responsible for the study at each school decided when the study was to be conducted and it was usually in the middle of the school year.
Students and their parents were informed about the study and assured of confidentiality, and that participation was voluntary. Signed parental consent was not required. Only one student chose not to participate in the study. The regional Ethical Committee of the Karolinska Institute approved the study.
Intervention
The intervention was defined as the application of the educational material with instructions and recommendations implemented by the student’s regular teacher or the school nurse during one lesson (45 min). The educational package contained: (1) a manual for teachers, (2) 10 overhead transparencies (animated comic figures), (3) a video tape (7 min), and (4) recommendations and instructions on how to behave in the sun (which were suggested to be photocopied and given to the students to take home). In the manual for the teachers, it was recommended to let the students work in groups and do several exercises. The students could then account for their work by making posters and/or websites. This was not included, however, in the intervention in the present study.
Prior to the intervention, all teachers in the study received written and verbal instructions on how to conduct the study, e.g. how and when to collect data. Participating teachers were asked to use the educational material as indicated in the manual. For ethical reasons, it was recommended that the control classes should be able to participate in the intervention immediately after the post-testing had been completed.
Assessments
The majority of the questions in the questionnaire have been used in several studies on sun-protection behavior and skin cancer in Sweden, and have been reviewed by dermatologists, oncologists and experts in skin cancer prevention (Brandberg et al., 1996, 1998; Jerkegren et al., 1999). The questionnaire was proved to be acceptable for face validity, readability and comprehension in students of the same age, i.e. in a school not participating in the evaluation study. The reliability of the items for assessing attitude and the stages of change has been assessed by the test–re-test method with a 3-week interval. Considering the subject and social desirability, the reliability is reasonable with most values over r = 0.70 for the attitude items and close to r = 0.70 for the stages of change items (unpublished data).
To measure the equivalence of the groups, demographic information was collected in the questionnaire. Skin type was categorized using the self-assessment method of Fitzpatrick (Fitzpatrick, 1988). Questions regarding hair color and sun-related behavior, such as how frequently the students sunbathed, got sunburned and traveled to a sunny resort, were also included.
To assess the effect of the intervention, the questionnaire included questions that quantified items in the following categories. (1) Students’ knowledge of the risk factors for skin cancer, UVR exposure and sun-protection behavior was assessed using 15 statements. Students answered these questions by checking one of three response choices (yes/no/don’t know). The scores were computed by counting the correct responses. An example of statement is ‘Many moles and/or freckles increase the risk of skin cancer’. (2) Attitudes towards sunbathing and tanning were assessed using five statements. The participants responded by checking on a five-point Likert-type scale (from total agreement to total disagreement). An example of statement is ‘I’m more attractive when I’m sun-tanned’. (3) Readiness to change five sun-protection behaviors was measured by assessing the stages of change modified from the TTM. Readiness to change five different sun-protection behaviors was assessed: (1) using clothes for sun protection, (2) avoiding the sun between 11 a.m. and 3 p.m., (3) using the shade for sun protection, (4) using sunscreen, and (5) giving up sunbathing.
Students were asked to check the one statement that applied best to them for each sun-protection behavior. For example, those who checked ‘I have never thought of using clothes to protect myself from the sun’ were defined as being in the precontemplation stage for changing this behavior. Those who checked ‘I’m thinking of using clothes to protect myself from the sun’ were classified as contemplators. Those who were classified as being in the preparation stage checked the statement ‘I intend to start using clothes to protect myself from the sun’. Students in the action stage checked ‘I have started to use clothes to protect myself from the sun’. Maintainers checked ‘I have used clothes for a long time to protect myself from the sun’. Similar statements were used for the other four sun-protection behaviors.
The method used to measure the stages of change in sun-protection behavior has been demonstrated to be sensitive to differences between subgroups in the general population and is therefore suitable for assessing an effect of the intervention (Kristjansson et al., 2001).
Data analysis
Two schools, or six classes (two Year 7 classes and four Year 8), were excluded from the data analysis because of procedural violations, leaving three schools and 10 classes available for analysis. One school did not adhere to the schedule and there were identification number violations in the questionnaires from the other one.
The effects of the intervention were analyzed by comparing mean scores on overall knowledge and attitude items at pre-test and post-test, using the paired samples t-test. Multi-item analysis was chosen for knowledge assessments because we wanted to measure the effect of the intervention on the students’ overall sun-related knowledge. When assessing the change in knowledge we also employed gain score analysis, using the independent samples t-test. This analysis was chosen because it is not complicated and will show if the intervention group has increased their knowledge score relatively more than the control group by comparing the mean change between the groups. Furthermore, we compared the groups with regard to the number of participants who had increased their knowledge between pre-test and post-test, using the 
2-test.
The effect of the intervention on readiness to change sun-protection behaviors was assessed by counting ‘advancers’ (those who progressed one or more stages). To compare the groups, we calculated a ratio of proportion (relative risk) with 95% confidence intervals based on the method of Mentel and Haenszel (Rothman, 1986). For example, a relative risk of 2.0 means that students in the intervention group are twice as likely to have progressed in their stage of change than the students in the control group.
There were no statistically significant differences across genders, school-year levels or schools in both the pre-test and post-test in all measured variables, and therefore they are not presented separately in the evaluation. The level of significance was P < 0.05 in all statistical analyses. Analyses were conducted using the statistical package SSPS for Windows (SPSS, 2000).
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Results |
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A total of 268 students completed the pre-test and/or post-test. Answers given by 84 students who completed only either the pre-test or post-test because of absence from school or identification-number violations were not analyzed. The answers given by 184 students who completed both the pre-test and post-test were analyzed at both the individual and the group level.
The intervention group and the control group were equivalent regarding gender, age, skin type, hair color and stages of change distribution (Table I). There was no statistical difference between the groups at baseline regarding the proportion of students that were able to progress in their stage of change. An exception was that the intervention group had a higher proportion of students who were able to progress in their readiness to give up sunbathing (P = 0.01) (not in table). There were no statistically significant differences between the groups in the pre-test with respect to relevant sun-related variables measures by analysis of variance. An exception was that the intervention group had more favorable attitude towards sunbathing and tanning.
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There was a statistically significant increase in correct answers between pre-test and post-test with regard to knowledge of UVR exposure, risk factors for skin cancer and sun protection in both the intervention group and the control group (Table II
). However, the mean gain score was greater in the intervention group than in the control group, 1.7 and 0.7, respectively (P < 0.05). Furthermore, the students in the intervention group were more likely to have increased their knowledge than those in the control group (61 versus 39%, P < 0.05).
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Four of five attitude items showed elevated mean score in the intervention group, which means less favorable attitude towards tanning and sunbathing. Two of these were statistically significant. Only one attitude item showed a statistically significant increase in the mean score in the control group (Table II
).
Overall, there was a larger number of students in the intervention group who progressed in their readiness to change sun-protection behaviors than in the control group. The exception was ‘giving up sunbathing’. This difference was statistically significant for ‘avoiding the sun between 11 p.m. and 3 p.m.’ (Table III). The alteration in readiness to change was seen primarily as progression from the precontemplation stage to the contemplation stage (not shown in table).
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Discussion |
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TopAbstractIntroductionMethodsResultsDiscussionConclusionReferences |
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The educational kit ‘You and Your Skin’ can be used in skin cancer prevention to enhance knowledge of the risks of skin cancer, UVR exposure and sun-protection behavior among adolescents. The effect of the intervention on the stage of change, modified from the TTM, was primarily a progression from the precontemplation stage to the contemplation stage. However, this effect was only significant for one of the five sun-protection behaviors measured. The effect on students’ attitude towards tanning and sunbathing was not significant. It has been reported that when children approach adolescence, their suntan appreciation increases (Hughes et al., 1993
; Pion et al., 1997). Therefore, it can be presumed that it will take a greater effort to achieve an attitudinal change in adolescents, and it might be better to start to motivate positive attitudes to sunbathing and tanning in childhood.
Several studies have shown that a knowledge of the risks of skin cancer is not always associated with better sun-protection behavior (Brandberg et al., 1996; Jerkegren et al., 1999). An increased knowledge of the risk of skin cancer alone may not be sufficient to bring about a behavioral change. However, according to the TTM, ‘consciousness raising’ is one of the most important processes of change for individuals in the precontemplation stage and is recommended for intervention targeting this group (Prochaska et al., 1994b). Thus knowledge or awareness and repeated reminders of sun-related hazards may be a necessary precursor to stages of change progression, and may finally lead to an attitude and behavior change. Furthermore, most teenagers may eventually become parents and there are indicators from smoking research that parents with high-risk awareness are more prone to protect their children from known risk factors, even if that knowledge may not affect the parents’ own behavior regarding exposure to the same risk factors (Lund et al., 1998; Helgason and Lund, 2001).
The intervention had an insignificant effect on the students’ readiness to change their sun-protection behaviors. The increase in readiness to change was statistically significant for only one of the five behaviors measured. The assessment of the readiness to change sun-protection behaviors, as used in this study, is, to our knowledge, the first attempt to use the stages of change construct as a parameter for the effectiveness of an intervention in skin cancer prevention. The conventional time frames used to assess the stages of change in, for example, smoking research were not used in this study. The rationale for this was that sun-related behavior is very much seasonal in Sweden. Our method has previously been proved to be sensitive to differences between two subgroups of the general population and was therefore judged to be applicable as a measure of readiness to change (Kristjansson et al., 2001).
Increased readiness to change sun-protection behavior may be an important indicator of an actual behavior change. It should be noted that, in this study, the advance in readiness to change was almost entirely from the precontemplation stage to the contemplation stage. There is a need for research on how well self-reported readiness to change predicts actual change in sun-protection behavior.
The majority of the students participating in this study and teenagers in general report positive attitudes to tanning and sunbathing (Brandberg et al., 1998; Buller and Borland, 1998). Therefore, it may be wise to inform them of different sun-protection strategies, i.e. how sunburn can be avoided in combination with education on the risks of skin cancer.
When designing this study we chose to use the regular teachers to implement the intervention and administer the data collection. The rationale was to evaluate the use of the educational material in a real-life setting. Using the schools’ regular staff increases the generalizability of the results, i.e. strengthens the external validity. The data collection was administered by the teachers with strict instructions regarding procedure to minimize potential bias.
We chose to draw an equal number of control and intervention classes in each school instead of dividing schools into control and intervention schools. This was done to minimize bias due to selection, i.e. differences in the socioeconomic status of students between schools and in local history effects, such as differences in health education policy between schools. This may, however, decrease the effect of the intervention due to contamination across the school classes. We chose the pre–post-test design because pre-testing is particularly important in a quasi-experimental study, but it may have an effect on the post-test outcomes. For example, one of the teachers of a control class reported that the questionnaire raised several questions and discussions in the class.
The intervention group had significantly more favorable attitude towards sunbathing and tanning at pre-test. Furthermore, the control group was somewhat more likely to be in the maintenance stage of sun-protection behaviors, but this difference was not statistically significant. These differences between the groups may have underestimated the impact of the intervention. Additionally, a possible intervention effect of the pre-test may partly explain the positive change in the control group between pre-test and post-test.
All data were gathered by self-reporting, and the results may be affected by social desirability and recall. Difficulties associated with research in educational settings, i.e. attrition and limited control, may have also affected the results. Six classes were eliminated from the study because the correct procedures were not followed. In some cases, the absence of statistically significant results may be due to power problems owing to a relative limited number of participants.
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Conclusion |
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The educational kit ‘You and Your Skin’ can be used to enhance a general knowledge of skin cancer prevention in teenagers in school settings. A more extensive intervention is probably needed to affect attitudes and the motivation to change sun-protection behaviors. Others have reported that multi-unit sun protection programmes produce a relatively larger effect compared with short-duration presentations (Buller and Borland, 1999
). Therefore, it is important to emphasize the necessity of using the educational kit as a multi-lesson programme with its several group exercises. The positive attitude towards tanning and sunbathing in this age group is an indication that there may be good reason to start skin cancer prevention education before adolescence.
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Acknowledgments |
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The authors thank the schools’ teachers, nurses and students for participating in this study. The Stockholm County Council and the Swedish Cancer Society supported this study.
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References |
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Received on May 15, 2001; accepted on February 1, 2002
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