The effect of ultraviolet radiation from a novel portable fluorescent lamp on serum 25-hydroxyvitamin D₃ levels in healthy adults with Fitzpatrick skin types II and III

Background/Purpose: Ultraviolet (UV) B irradiation may provide a safe and effective method to treat vitamin D deficiency. The objective of this study was to assess the effectiveness of a novel Sperti D/UV-Fluorescent lamp in converting 7-dehydrocholesterol (7-DHC) to previtamin D₃ in vitro and in raising serum 25-hydroxyvitamin D₃ [25(OH)D₃] in healthy adults. Methods: The lamp was assessed in vitro using a 7-DHC solution and a human skin sample. In a prospective cohort study, five healthy adults with skin types II and III were exposed to a 0.75 minimal erythemal dose of UV radiation over ∼9% of body surface area three times a week for 4 weeks. The main outcomes were percentage of conversion from 7-DHC to previtamin D₃ in vitro and changes in serum 25(OH)D₃ after irradiation in vivo. Results: A dose response between UV irradiation time and conversion of 7-DHC to previtamin D₃ was seen in the 7-DHC solution and surgically obtained human skin. The subjects had a significant increase in mean 25(OH)D₃ from 18.4±8.2 to 27.3±7.6ng/ml (P<0.001) after 4 weeks of irradiation. No adverse events occurred. Conclusion: The Sperti D/UV-Fluorescent lamp is effective in converting 7-DHC to previtamin D₃ in vitro and in raising serum 25(OH)D₃ in healthy adults.