Randomised controlled trial assessing effectiveness of health education leaflets in reducing incidence of sunburn

Exposure to the sun and severe sunburn are associated with an increased risk of malignant melanoma.1 Health education leaflets are often part of primary prevention strategies which aim to modify high risk behaviour related to the sun.2 This study aims to assess the effectiveness of a health education leaflet in reducing sunburn.
Subjects, methods, and results
The study population comprised holidaymakers travelling on Air UK Leisure flights from Manchester airport during August 1993. The unit of randomisation was the flight. Flights were stratified into long haul (North America and Jamaica) and short haul (Europe) and randomly allocated to the intervention or control arm. Before boarding, the health education authority leaflet If You Worship The Sun, Don't Sacrifice Your Skin was placed in seat pockets on flights in the intervention arm but not in the control arm. Cabin crew distributed questionnaires to passengers on Air UK Leisure return flights to Manchester. A history of sunburn was elicited by the question “Did you suffer from any sunburn during your recent holiday?” and, if so, whether this was associated with one or more of: redness of the skin, blistering of the skin, pain for less than a day, pain for more than a day. Adults completed the questionnaire for children. The study endpoint, severe sunburn, was defined as any episode of sunburn which was either painful for more than a day or resulted in blistering. Randomisation by group was undertaken to reduce contamination between the study arms. A clustering parameter was calculated for the study endpoint. Brier's adjusted χ2 was used for baseline comparisons,3 and 95% confidence intervals were constructed for the difference in proportions using methods appropriate to group randomised trials.4
Sixteen long haul and 62 short haul flights were randomised to the intervention arm and 15 long haul and 62 short haul flights to the control arm; 21611 questionnaires were distributed and 14956 (69%) returned. A total of 2483 questionnaires completed by passengers who had not departed from Manchester airport during the study period and 88 inconsistent or illegible questionnaires were excluded from the analysis, leaving 12385 evaluable questionnaires. The clustering parameter was 0.02. The study had a power of 90% to show a 5% difference between the two groups at the 5% two sided significance level. There was no significant difference between the two groups in the distribution of baseline characteristics or the proportion reporting severe sunburn (see table).