Assessment of ultraviolet radiation exposure in preschool children attending kindergarten: an exploratory study

Exposure to solar ultraviolet radiation (UVR) during childhood increases the risk of skin cancer later in life. Little is known regarding the extent of UVR exposure in children, particularly those aged 3-6 years. In this exploratory study, we investigated individual UVR exposure among Danish kindergarten children during the summer, by including children from two distinct types of kindergarten: a traditional Danish kindergarten with a playground (n = 17) and a forest kindergarten where children spend the entire day in a forest setting (n = 20). Children wore personal electronic wrist borne dosimeters, and their clothing coverage was recorded from 9:00 to 11:00 h, 11:00-13:00 h, and 13:00-15:00 h. The study included a sunny day and a cloudy day, and a ground station near both kindergartens measured ambient UVR on the same days. On the sunny day, children from the forest kindergarten received 2.4 standard erythema doses (SEDs; range 0.8-3.6; 7.6% of ambient UVR). This was significantly higher than the 1.0 SED (range 0.4-1.8; 3.4% of ambient UVR) received by children from the traditional kindergarten (p = 0.0000073). On the cloudy day, the forest kindergarten children also received significantly more UVR (1.3 SED; range 0.6-2.1; 5.3% of ambient UVR) than the traditional kindergarten children (1.0 SED; range 0.2-1.6; 4.3% of ambient UVR), but it was not significant (p = 0.056). Notably, the forest kindergarten children wore significantly more clothing. Children in both types of kindergarten received relatively high UVR doses. This highlights the importance of implementing sun protection strategies during kindergarten hours.