Vitamin D and UV exposure in construction workers-a randomized control trial using text messaging to promote positive behaviours.

Background
The aim of this study was to determine whether a text messaging intervention (supported by a smartphone application) would be effective in the promotion of sun-safe behaviours. Both excessive and insufficient exposure to ultra-violet (UV) radiation were considered.

Methods
A randomized control crossover trial was conducted. 112 participants from nine sites in the United Kingdom contributed to the study. There were three intervention waves, two in winter (Vitamin D-focussed) and one in summer (UV exposure-focussed). Stages of Change, Standard Erythemal (UV) Dose and assayed blood samples (Vitamin D) were employed to evaluate the effectiveness throughout the 21-day data collection periods.

Results
The intervention was effective in promoting positive progression in Stages of Change for Vitamin D; and this in turn was predictive of increased Vitamin D levels in participants. More limited positive findings were found with respect to UV exposure. Overall, for those in the Intervention, Vitamin D levels were significantly predicted to increase during both of the winter data collection waves.

Conclusions
Interventions of this type are recommended to promote healthy Vitamin-D levels in construction workers.