The SDHW was effective with children in grades 6, 7 and 8. It had a positive impact on a broad range of outcomes, including theoretical precursors to behavior change and reported sun protection behavior. The effects of SDHW reported here, coupled with evidence that these effects occurred through a pathway of theoretical mediation based on social cognitive theory - improved knowledge, reduced barriers, and elevated self-efficacy expectations - as reported elsewhere24
suggests that the behavior change strategies in SDHW influenced children to improve their sun protection, not merely exposure to information on sun safety. Furthermore, these effects were detected within scales validated in our pilot study or by correlations with colorimeter measures in the trial. Validation of sun protection measures has been rare.26
The intent-to-treat analyses also appeared to rule out biases due to drop out in all but the most conservative case where it was assumed that all drop outs did not engage in sun protection. This is unlikely as only one of the differences between children lost and not lost to follow-up could plausibly be expected to be related to sun protection. More Hispanic white children were lost to follow-up and this group may be expected to engage in lower sun protection. However, the loss of this group occurred primarily in a single control school where it actually might make it less likely that SDHW produced improvements (i.e., higher sun protection reports by the non-Hispanic white students in a control school would reduce the apparent observed difference with the paired intervention school). It is more plausible that the sun safety behavior of children who were lost was stable over time (i.e., that past behavior was the best predictor of future behavior) and that the intent-to-treat analysis employing pretest values as estimates at posttest provided the most accurate evaluation. Under this assumption, the SDHW improved sun protection, so our confidence that it was an effective intervention for young adolescents is strengthened.
Thus it was concluded that the SDHW was effective with middle school students and can be effectively implemented by teachers with minimal training. This is the first trial to report positive effects of a multi-unit sun safety curriculum for secondary schools. Under criteria used by the Community Preventive Services Task Force10
– use of group-randomized procedures and validated measures – the results are “strong” evidence that an educational approach is effective in early secondary school grades.
The impact of the middle school SDHW is comparable to that produced by primary school SDHW: SDHW improves knowledge and creates positive attitudes toward sun protection and increases self-reported sun safety by children. Notably, the effectiveness of the primary school SDHW declined in the oldest primary grades.14,15
Additional behavior change strategies were incorporated from social cognitive theory in the middle school version such as goal setting, coping strategies to overcome barriers, and environmental analysis to bolster its effectiveness with older children. These strategies may in part account for its success in grades 6–8.
This trial does not provide evidence on whether SDHW will remain effective into high school years, but age did not moderate the SDHW’s effect suggesting it may influence older children. Still, the SDHW’s effects were relatively small in grades 6–8 and it influenced some but not all prevention behaviors. It may be unreasonable to expect that school programs alone will produce large improvements in sun protection and should be coupled with other community-wide efforts.
It is also notable that SDHW was effective during early adolescence. This is a time of increasing independence and is marked by a decline in sun protection and emergence of sun tanning norms.27
These trends should work against SDHW; therefore, to find any evidence of positive outcomes indicates that the SDHW was quite persuasive. However, outcomes were tested only in the short term. UVR in the study region was sufficiently high to sunburn the skin by the end of May, but this introduced a seasonal confound (i.e., more sun protection practiced later in the study period because of the seasonal increase in UVR). The seasonal trend actually should have made it more difficult to detect an effect because the control group was increasing its sun protection, too. Further data is needed from the summer to determine whether SDHW improved protection during the highest UVR season.
Another unanswered question is whether the favorable impact of SDHW will be improved through repeated instruction over more than a single year. Booster sessions improved substance abuse prevention programs and primary school SDHW was more effective when taught again in a second year.14
Unfortunately, there are substantial challenges to multi-year presentation because many schools do not provide health education each year, health education often is an opt-in program that reaches only some students, and sun protection must compete for instructional time with other health issues that are considered more important to schools or with other topics when integrated into science classes.
The curriculum showed the broadest effects within the composite frequency measure rather than the diary measure. The diary measure of body coverage may have been less sensitive to changes because it focused only on the school day. Time outdoors is more limited in middle school then in primary grades and children may have less control over their attire in physical education classes. The lack of effects on individual items within the composite was surprising. The SDHW instructed children to increase all of their protection behaviors but some of these behaviors are alternatives for one another – e.g., sunscreen is unnecessary if one avoids the midday sun. Given this substitution of protection strategies, a composite measure may be the best way of detecting a general increase in all prevention strategies.
It appears that children in this trial, like many adults, have a preference for using sunscreen as a primary means of protection. Sunscreen is not as effective a protection strategy as other methods that actually block or reduce exposure. People often use it to prolong time outside, apply too little of it, and do not reapply it to receive the maximum protection. It could not be determine precisely how sunscreen was used; however, the SDHW was designed to teach children the value of using methods that physically block or reduce exposure (i.e., wearing protective clothing and hats, limiting time outdoors, staying in the shade) and how to properly apply and reapply sunscreen. Children may not have as much control over time outdoors during school; however, they do decide what they wear and exposure to SDHW was associated with increased use of long-sleeved shirts during recess. A catalyst for this change may be school districts’ prohibitions against skin-revealing clothing articles, although these restrictions also may produce psychological reactance in children that create a desire to wear skimpier clothing.
There were several limitations to this trial. Active parental consent may have created a selection bias, yielding a sample with less risky sun exposure that SDHW was more likely influence. The project was conducted only in three states, limiting its generalizability, although they were states with high UVR. A quarter of the population was comprised of minority groups with darker skin tones at lower risk of skin cancer, which mitigated against finding favorable effects. However, this sample was more diverse than in previous SDHW evaluations and suggests that it will be effective in populations with greater ethnic diversity. The follow-up period was very short; data is reported elsewhere that shows persisting effects of SDHW over the summer. The composite behavior measure had low reliability, perhaps due to the substitution of alternative protection behaviors mentioned earlier. The self-reports also could be affected by social desirability tendencies. Our measures of implementation fidelity were sparse making it impossible to detect effects of implementation on curriculum outcomes. The effect of testing was not controlled in the experimental design. However, using a Solomon four-group design, testing was found to affect the recognition of terms not knowledge or behavior in a previous trial evaluating the primary school SDHW.15
The secondary school environment is an effective venue for delivering effective sun protection education to children. A priority is to convince schools to implement evidence-based educational approaches. Also, developing effective materials for non-school environments, either in place of or as an adjunct to, curricular programs is another priority because sun safety. Finally, the case for disseminating sun safety instruction to schools would be strengthened by replicating the results of this trial elsewhere, by documenting that an educational approach in secondary schools can have long-term positive impact, and by demonstrating that this type of program can be effective in high schools.