We would investigate in a controlled, randomized open study in the winter season: 1) If serum levels of vitamin D (25(OH)D) increase in subjects treated with sunbed with sunlamps emitting mainly UVA and only 0·5% or 1·4% UVB compared to non-sunbed treated controls 2) If yes, are the 25(OH)D serum levels then dependent on the UVB dose?