2.1 Design
We conducted a feasibility study of a wait-list controlled trial, with five schools allocated by the research team to an intervention group and one school to a wait-list control group. The last school to be recruited was allocated to the control group. The study was conducted in the United Kingdom between June and September in 2018.
2.2 Study population and recruitment
The criteria for inclusion in the study were males and females aged between 13 and 15 years. Head teachers of 132 schools in 6 local authorities were contacted by email about the study. Schools were followed up by telephone calls if the head teacher expressed interest in participating in the study. Recruitment stopped once six schools consented to participate.
For each participating school, study information booklets were distributed to all parents/carers of all eligible students on the school roll, including a form that could be returned if the parent/carer did not assent to their child’s participation in the study. Contact details for the research team were included in the booklet, allowing parents/carers the opportunity to contact the research team if they wished to discuss the study. Students whose parents did not opt them out of the study were provided with a verbal overview of the study by a researcher, a study information booklet and consent form. For those students who were opted out of the study by parents/carers and those that did not consent to participate, alternative educational opportunities were provided by the school whilst their classmates participated in the study.
2.3 Intervention description
The intervention being tested was refinement of our previous intervention [29]; two intervention components were the same (Components 1 and 2) and our previous study shows that these components improve sun safe intentions [29]; the third additional component was novel and had not been previously tested. The intervention was designed in accordance with two theoretical models - CSM and HAPA. The intervention was developed to address social cognitions by changing beliefs about skin cancer, evoke an emotional response to skin cancer, and shift sun protection intentions to actual behaviour by including action and coping planning.
Component 1: Information delivered during a presentation was designed to address key CSM dimensions (cause, consequence, identity, risk perception, controllability) and included information about personal experiences of skin cancer, incidence patterns, risk factors, associations between disease staging and survival, and benefits of skin self-examination (SSE). The presentation also briefly touched on appearance. A skin cancer nurse specialist delivered the 50-minute presentation on one occasion during the school day in a classroom or hall. After playing a 5-minute film ‘Dear 16-year-old me’ (http://dcmf.ca), the nurse delivered the presentation with the aid of Microsoft PowerPoint slides. A young adult skin cancer survivor gave a brief 5-minute talk after the nurse-delivered presentation. The talk was about his personal experience of melanoma diagnosis at 16 years old, impacts on his life and his views on sunscreen use and SSE. The film and the young person’s talk aimed to evoke an emotional response to skin cancer.
Component 2: This intervention component was based on the HAPA and aimed to shift intentions to use sun protection and conduct SSE by making plans to conduct these behaviours. A booklet with instructions to write sun protection and SSE action plans was handed to students at the presentation. The booklet also included information about sunscreen use and SSE. Adolescents were asked to complete an action plan for regular monthly sunscreen use and an action plan for SSE. The SSE component of the booklet for instance, had three sections: a) information on the importance of planning; b) instructions of what should be included in the plan; c) formulating ‘if-then’ action plans (e.g., If I am having a shower then I will check my skin) and coping plans (e.g. To make sure I don’t forget, I will add the appointment to my calendar and put a reminder post-it on the fridge).
Component 3: Automated text messages were delivered on two days of the week for seven weeks after the 50-minute presentation. Messages were developed by the study investigators to apply to key theoretical CSM dimensions and address appearance. A total of 14 messages were developed. These messages were tailored to the target audience following feedback from a focus group of students (n= 13) who attended one of the participating schools. Participants were shown the messages that the study investigators developed and were asked to provide feedback, including how to make the text messages more likely to motivate themselves to protect their skin. Messages that the participants indicated that they did not like were removed from the list or were revised based on specific suggestions. Messages contained information around sun safety behaviours and information about the effects of excessive exposure to the sun (Table 1). Messages were scheduled in the morning on a Monday and Friday.
2.3 Assessing intervention reach, adherence, impact, acceptability
Reach and adherence
Intervention reach was objectively measured using school attendance records. Reach was defined as the proportion of students on the school register who attended the presentation and given the booklet (intervention components 1 and 2) and gave their mobile number (component 3) at the time they consented to the study. Adherence was self-reported by students at follow up and defined as the proportion of consenting students who received the presentation (component 1), read the booklet (component 2), and received text messages (component 3).
Impact
Five-point continuous rating scales were used to assess students’ views about the impact of each intervention component. For example, to assess the perceived impact of component 3 (text messaging) 2 items were used to assess perceived impact: i) ‘On a scale of 1 to 5, did the text messages about sun safety increase the ways that you protected your skin from the harmful effects of the sun? e.g. using sunscreen, staying in the shade etc.’ ii) ‘On a scale of 1 to 5, did the text messages about sun safety influence whether you examined your skin for signs of possible skin cancer?’ Students answered each question using a scale of 1 (definitely did) to 5 (definitely did not).
Acceptability
Focus groups to elicit adolescents’ views on the acceptability of the intervention were conducted approximately 12 weeks after Component 1 of the intervention in each of the four intervention group schools. Focus groups were audio-recorded and took place during school time, in a classroom, at a time and place selected by the teacher and lasted approximately 20 minutes. Confidentiality was explained and informed consent was obtained in writing.
2.4 Variables and measures
Outcome variables were measured before the school summer holidays in June (baseline) and after the summer holidays in September (follow-up). Student responses were paired between the two timepoints via use of unique identifier after all questionnaires had been anonymised. Objective measures of sunburn and tanning were collected by two researchers in the classroom. A self-completed pen and paper questionnaire was completed by students in the classroom. Items for the self-report questionnaire were recommended by an international working group to measure sunburn and sun protection behaviours [43] and/or used in our previous study [29].
Objective measures of skin colour
The feasibility of objectively measuring sunburn and tanning was assessed by measuring skin colour using a Mexameter, giving a “melanin index” calculated from the intensity of the absorbed and the reflected light at 660 and 880 nm and an “erythema index” from 568 and 660 nm[44]. Three readings were made, each taking only a few seconds, on the right or left dorsal forearms (likely to be exposed to UV radiation) and behind the left or right ear (unlikely to be exposed to UV radiation).
Self-reported sunburn, severity and body location
Self-reported sunburn was measured using one item: ‘For people with white skin, sunburn is red skin that appears a few hours after being out in the sun and then fades after a few days. For people with naturally dark skin, sunburn is less visible but the skin feels hot in the sun and stays hot and is painful afterwards for a few days. During the last summer holidays, how many times did you have a red OR painful sunburn that lasted a day or more? Students had nine options to choose to report how many times they had sunburn from 0 to ³8.
Sunburn severity was measured using one item: ‘Which one of the following best describes your worst case of sunburn during the last summer holidays?’ Students had seven options to choose how to report severity: ‘Skin got hot and stayed hot for a couple of days, Skin went pink or slightly red, Skin went red but not sore, Skin went red and sore, Skin went red, sore and blistered, or I did not get sunburnt during the summer holidays.’
Body location was measured using one item: ‘Where on the body was your worst case of sunburn during the last summer holidays?’ Students had seven options to choose to report where on the body their worst case of sunburn occurred: ‘back, chest, leg or foot, arm or hand, shoulder or neck, head or face, or I did not get sunburnt during the summer holidays.’
Self-reported tanning
Three items were used to measure tanning: i) ‘Last summer did you get a suntan?’ Students had three options: ‘yes, no or don’t know’; ii) ‘How many days did you sunbathe last summer to try to get a suntan? (by sunbathe, we mean that you stayed out in the sun because you wanted your skin to go browner or more golden in colour). Students had four options ‘0 days, 1 to 5 days, 6 to 10 days, 11 or more days’. iii) ‘At present, do you use a sun-tanning bed (either at home, in a spa or a tanning shop on high street)’. Students had three options: ‘yes, no or don’t know.’
Sun protection behaviours
Four items were used to measure sun protection behaviours: ‘For the following questions, think about what you did when you were outside during the last summer holidays on a warm sunny day: i) How often did you wear SUNSCREEN? ii) How often did you wear a SHIRT WITH SLEEVES that cover your shoulders? iii) How often did you stay in the SHADE or UNDER AN UMBRELLA? iv) How often did you wear SUNGLASSES?’ Students had four options: ‘never, rarely, sometimes, often’.
Skin self-examination (SSE)
One item was used to measure SSE: ‘In the past month, have you examined your skin for signs of possible skin cancer?’ Students had three options: ‘yes, no or don’t know.’
Social-demographic characteristics
Socio-demographic questions were included to gather data on age, gender and ethnicity.
2.6 Analyses
As this was a feasibility study, the quantitative data were analysed using descriptive statistics. Baseline measurements were reported as n (%) for categorical data and mean (standard deviation) for continuous variables. The melanin and erythema indices were summarized as the arithmetic mean of the three readings taken on the forearm, and the arithmetic mean of the three readings taken behind the ear. Changes in the outcome measures were analysed within individuals (paired analysis) and reported in cross-tabulations (pre- and post- intervention) for categorical variables and as mean (standard deviation) of within-individual changes for continuous variables.
The control group was included in the study solely to determine the feasibility of recruitment of such a group. Thus, the more detailed results reported in this manuscript only include participants in the intervention group, to describe the outcomes pre- and post-intervention and the participants’ subjective views of the intervention impact. Only complete data (i.e., individually paired baseline and follow up sampled data) are included.
Audio-recorded qualitative data from focus groups were transcribed verbatim and analysed thematically using the Framework approach [45]. Qualitative findings provided contextual and explanatory understandings of adolescents’ experiences of the intervention.