Sun protection at elementary schools: a cluster randomized trial

Abstract

Background: Elementary schools represent both a source of childhood sun exposure and a setting for educational interventions.

Methods: Sun Protection of Florida's Children was a cluster randomized trial promoting hat use at (primary outcome) and outside of schools among fourth-grade students during August 8, 2006, through May 22, 2007. Twenty-two schools were randomly assigned to the intervention (1115 students) or control group (1376 students). Intervention schools received classroom sessions targeting sun protection attitudes and social norms. Each student attending an intervention school received two free wide-brimmed hats. Hat use at school was measured by direct observation and hat use outside of school was measured by self-report. A subgroup of 378 students (178 in the intervention group and 200 in the control group) underwent serial measurements of skin pigmentation to explore potential physiological effects of the intervention. Generalized linear mixed models were used to evaluate the intervention effect by accounting for the cluster randomized trial design. All P values were two-sided and were claimed as statistically significant at a level of .05.

Results: The percentage of students observed wearing hats at control schools remained essentially unchanged during the school year (baseline = 2%, fall = 0%, and spring = 1%) but increased statistically significantly at intervention schools (baseline = 2%, fall = 30%, and spring = 41%) (P < .001 for intervention effect comparing the change in rate of hat use over time at intervention vs control schools). Self-reported use of hats outside of school did not change statistically significantly during the study (control: baseline = 14%, fall = 14%, and spring = 11%; intervention: baseline = 24%, fall = 24%, and spring = 23%) nor did measures of skin pigmentation.

Conclusions: The intervention increased use of hats among fourth-grade students at school but had no effect on self-reported wide-brimmed hat use outside of school or on measures of skin pigmentation.

Figure 1

Comparison of intervention and control schools in the Sun Protection of Florida's Children project.

Figure 2

Changes in skin pigmentation among intervention and control students from baseline to fall, fall to spring, and baseline to spring. Pigmentation was assessed by use of a DermaSpectrometer on a subgroup of 378 students (178 in the intervention group and 200 in the control group) during the three assessment periods throughout a school year. We assessed skin pigmentation at a child's forehead as a representative anatomical site that would be protected by hat use. An increase in the DermaSpectrometer readings denotes an increase in melanin, resulting in darkening of the skin. Lighter-skinned students are students with a baseline DermaSpectrometer reading (range = 0–100) that was less than or equal to the median of 20 in the control group and the intervention group. Darker-skinned students were students with a baseline DermaSpectrometer reading (range = 0–100) that is greater than the median of 20 in the control arm and the intervention arm.