Weber B, et al. - In this single-centre, prospective, open observational study involving 101 patients, researchers ascertained if exposure to narrowband UVB phototherapy (NB-UVB) alters serum folate or cobalamin (vitamin B12) levels. Participants in the study were patients subjected to NB-UVB phototherapy between late fall and early spring. After 0, 12, 24 and 36 NB-UVB exposures, serum folate, 25(OH)D and cobalamin levels were measured. A significant decrease in mean serum folate and cobalamin levels was noted after 12 NB-UVB exposures, although serum levels of 25(OH)D exhibited a significant increase.