Holiday sun exposure increases level of vitamin D and thymine dimmers in children

Abstract

Introduction: Sun exposure involves to synthesis of vitamin D, which is associated with many processes in the human body. The aim of the study was to determine the effect of UVR on the synthesis of vitamin D and DNA damage in the population of children including the individual radiation dose.

Material and methods: The study was conducted on a group of 32 children during 2-week stay by the Baltic Sea. Blood samples were taken to measure levels of vitamin D, PTH, cross-laps and osteocalcin, and urine samples for analysis of DNA damage based on the concentration of thymidine dimers (T = T). Measurements were performed 24 hours before and 24 hours after returning. Statistical analysis revealed significant difference in PPF values measured on forehead and on upper and lower arm.

Results: Positive correlation between PPF on the forehead and change (Δ) 25(OH)D was founded. Median value of 25(OH)D after camp increased statistically comparing to baseline level. Levels of PTH, osteocalcine and cross-laps didn’t differ significantly after sun exposure. T = T levels increased statistically significant after esposure and higher values was obtained among the children with I/II phototype. Statistical analysis gave no significant correlations between T = T levels and vitamin D concentration.

Conclusions: The results show both beneficial and harmful effects of natural sun exposure on children’s health. Increase of vitamin D levels and on the other hand increase in T = T synthesis are confusing to be interpreted. Therefore, it still seems to be valid to conduct research involved individual exposure to sunlight, UVR protection and supplementation of vitamin D.