Nudging construction workers towards better sun safety behaviour

Excessive exposure to solar ultra-violet (UV) radiation can cause skin cancer. However, inadequate
exposure to sunlight limits the production of vitamin D. There is very little research on understanding
the barriers to adopting sun-safe behaviours in the workplace and encouraging behaviours that
ensure vitamin D sufficiency. We report findings from a text messaging (SMS) and supportive
smartphone app intervention, that aimed to reduce UV exposure in the summer and promote
appropriate dietary changes and/or supplement intake to boost vitamin D status in the winter. Sixtysix adult construction workers were recruited from central Scotland and southern England from nine
construction sites. A randomised control crossover trial design was used, with randomisation to the
intervention at site level. The intervention messages were delivered daily to participants’
smartphone along with a supportive app and appropriate supportive measures such as vitamin D
supplements during the winter intervention and sunscreen during summer. The main outcome
measure was 25-hydroxy-vitamin D in blood, taken at the start and end of each study period. There
were three waves of data collection across 2017 (winter, summer and winter) with each study period
lasting 21 days. Results suggest: (i) many workers in our study had insufficient circulating vitamin D in
winter, but for the intervention group vitamin D levels increased significantly compared to the control
group; (ii) in the summer workers were exposed to relatively high UV levels from the sun, sufficient
for many to have their risk of being diagnosed with skin cancer doubled if the exposure continued
over their whole working life; few participants had insufficient levels of vitamin D during summer; (iii)
the sun-safe intervention failed to reduce exposure to solar UV and failed to reduce vitamin D levels
in summer, as we hypothesised; (iv) psychological aspects suggested the intervention had a positive
effect on taking action to use sun protection measures in summer (e.g. sunglasses) and preparation
to increase vitamin D intake during winter, but a key barrier to the success of the summer intervention
appears to be the entrenched belief that a sun tan is desirable. This study provides important
information about the effectiveness of a technology-based intervention to promote sun-safe and
healthy behaviours. This demonstrates that text messaging and a supportive app provides an easy and
accessible method to communicate with workers. We argue that a more prescriptive risk-based
approach is needed to reduce the risk of skin cancer among outdoor construction workers.