BMJ 2009; 338 doi: https://doi.org/10.1136/bmj.b95 (Published 17 February 2009)Cite this as: BMJ 2009;338:b95
Objective To examine whether students use or avoid newly shaded areas created by shade sails installed at schools.
Design Cluster randomised controlled trial with secondary schools as the unit of randomisation.
Setting 51 secondary schools with limited available shade, in Australia, assessed over two spring and summer terms.
Participants Students outside at lunch times.
Intervention Purpose built shade sails were installed in winter 2005 at full sun study sites to increase available shade for students in the school grounds.
Main outcome measure Mean number of students using the primary study sites during weekly observations at lunch time.
Results Over the study period the mean change in students using the primary study site from pre-test to post-test was 2.63 (95% confidence interval 0.87 to 4.39) students in intervention schools and −0.03 (−1.16 to 1.09) students in control schools. The difference in mean change between groups was 2.67 (0.65 to 4.68) students (P=0.011).
Conclusions Students used rather than avoided newly shaded areas provided by purpose built shade sails at secondary schools in this trial, suggesting a practical means of reducing adolescents’ exposure to ultraviolet radiation.
Trial registration Exempt
Our main hypothesis was that the mean number of students using the primary study sites in intervention schools would increase after installation of the purpose built shade compared with students’ use of equivalent unshaded sites in control schools. We monitored shade avoidance by observing changes in students’ use of the unshaded alternative study site in intervention compared with control schools.
The primary outcome measure used to assess the effect of the intervention was the change in the mean number of students using the primary site during lunch times in spring and summer terms before (pre-test, 2004-5) and after (post-test, 2005-6) installation of the shade sail intervention. The secondary outcome measure used to assess shade avoidance was the change from pre-test to post-test in the mean number of students using the alternative site.
None of the schools reported any vandalism to the shade sails or injuries resulting from building the sails.
We found this shade sail intervention to be effective, with greater use of the newly shaded areas by students at intervention schools compared with full sun areas at control schools. Furthermore, we found no evidence of shade avoidance. The study was implemented with no drop out of schools.The mean change in use of the primary study sites between control and intervention schools was relatively small; an average of approximately three more students used the shaded sites at intervention schools compared with unshaded primary sites at control schools. Nevertheless, we believe the findings are important because no other rigorous studies of the effects of environmental approaches alone for skin cancer prevention have been done.17 Moreover, adolescents have been intransigent in their use of sun protection,7 8 and this is one of the few interventions that has had an effect on adolescents’ sun protective behaviours. Researchers have been pessimistic about succeeding in this area.7 10 11 To highlight how challenging producing positive change in sun protection behaviour among adolescents is, one of the two other successful intervention trials for adolescents described positive outcomes in terms of stalling the decline in sun protection after two years of intervention.18 The other successful study found that relatively small improvements in use of sunscreen and long sleeved clothing were possible for young adolescents after a one year intensive curriculum.19
This study provides clear evidence that secondary school students will use rather than avoid shade sails in schools when location and shade design have been carefully selected. Although more research is needed to identify factors that will maximise students’ use of shade sails, these findings suggest that investing in shade in schools has potential for reducing students’ exposure to ultraviolet radiation during school hours.
A purpose built shade sail intervention increased students’ use of newly shaded areas at schools
Building shade is an effective practical option for protecting students against ultraviolet radiation during lunch .times
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