Study Status: Completed
Recruit Status: Completed
Study Type: Interventional
Official Title: The Role of Narrowband Ultraviolet B Exposure in the Maintenance of Vitamin D Levels During Winter
Brief Summary: The investigators investigated the ability of narrowband ultraviolet B (nbUVB) treatment in the maintenance of vitamin D levels achieved during the summer in Finland. The investigators randomized 37 subjects into groups of 17 and 18 subjects. The other group received 2 standard erythema doses (SED) nbUVB exposure every other week until week 24, and serum 25(OH)D levels were measured at the onset and at weeks 6, 14, 20, 26 and 30. The control group was not illuminated and serum samples were analyzed correspondingly. Punch biopsies were taken at the onset and at week 14 for CYP27A1 and CYP27B1 enzyme expression level analyses.