Abstract
Background:
New Zealand (NZ) has the highest incidence rate of melanoma skin cancer in the world. Although most cases of melanoma, and other skin cancers, can be prevented by reducing sunlight exposure, sun-safety interventions have received little policy and research interest in NZ. Previous international research has identified school-based sun-safety interventions as an effective and cost-effective strategy for reducing skin cancer risk.
Aim:
This study aimed to observe sun protection among children in Wellington primary schools, and assess whether a sun-safety intervention implemented in NZ schools could be cost-effective in terms of preventing skin cancer.
Research design:
The project was conducted in two phases:
Phase 1:
Methods: existing data from the Kids’Cam project was used to study the sun-safety practices of Wellington primary schools and schoolchildren. The Kids’Cam project provided wearable cameras that automatically took pictures every seven seconds to 169 schoolchildren from 16 intermediate schools in the Wellington region. In this thesis, a random sample of 15 Kids’Cam participants was selected from eight schools during the summer terms. For each participant, a systematic sample of ten percent of photos taken during school lunch breaks was extracted. The clothes worn and shade used by children observed in the photos was recorded. The type and composition of each type of shade was also recorded. School staff members were surveyed about their school’s sun-safety policies.
Results: One thousand two hundred and ninety-eight students and 108 shade structures were observed. Although six of the eight schools had a sun-safety policy encouraging hat use, only 28% of students wore hats. Twenty-two percent of students were observed using shade. Large built structures providing cover over seating areas were more likely to be used than smaller structures.
Phase 2:
Methods: a school-based shade intervention, designed after consultation with the Health Promotion Agency, Cancer Society and other relevant stakeholders, was modelled for cost-effectiveness using TreeAge Pro modelling software. A Markov model was designed using NZ data and other published sources. A cost quote was obtained for built structures measuring 8m by 10m and composed of a polycarbonate canopy supported by aluminium frames and galvanised steel posts. Intervention effectiveness was estimated in terms of reducing melanoma, basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) risk. One-way and probabilistic sensitivity analysis were performed to test uncertainty in model parameters.
Results: The incremental cost per quality-adjusted life year gained from the shade intervention was NZ$37,469. For a hypothetical cohort of 100,000 schoolchildren, the shade intervention was calculated to prevent 61 melanoma, 1392 BCC and 383 SCC cases, and five melanoma, two BCC and one SCC deaths. The likelihood of the intervention being cost-effective, given joint parameter uncertainty, was 68.8% at a willingness to pay threshold of NZ$50,000 per quality-adjusted life-year gained.
Conclusion:
Most children did not wear a hat or use shade. School-based sun-safety interventions should be encouraged to improve hat wearing and shade use in NZ primary and intermediate schoolchildren. The construction of large shade structures could be a feasible option, and would likely be a cost-effective investment in terms of reducing skin cancer risk.