Phototherapy of psoriasis is an effective treatment. In addition to standard broadband ultraviolet radiation B (UVB), (280–320 nm), narrowband phototherapy (NBUVB) (monochromatic UV between 311 and 312 nm) has become an important treatment for psoriasis. The same wavelength range of UVB (290–315 nm) induces synthesis of vitamin D. The aim was to compare the effect of broadband with NBUVB therapy on vitamin D synthesis in patients with psoriasis.Methods:
Sixty-eight Caucasian patients (17 women and 51 men) mean age 54.1 ± 16.0 years, with active plaque psoriasis, were treated with broadband UVB (n=26) or NBUVB (n=42) two to three times/week for 8–12 weeks. The serum concentrations of 25-hydroxyvitamin D (25(OH)D3), 1,25-dihydroxyvitamin D (1,25(OH)2D3), intact parathyroid hormone (PTH), calcium and creatinine were measured before the first exposure and after the last dose of radiation.Results:
In broadband UVB treated patients, 25(OH)D3 increased from 37.9 ± 16.9 to 69.4 ± 19.7 ng/ml (P<0.0001) and in patients treated with NBUVB from 34.8 ± 11.9 to 55.3 ± 17.6 ng/ml (P<0.0001) and P=0.008 between the treatment groups. PTH decreased on broadband UVB (P<0.05). The serum concentrations of 1,25(OH)2D3, calcium or creatinine remained unaltered.Conclusion:
Serum 25(OH)D3 in psoriasis patients increased less with NBUVB than with broadband UVB phototherapy. Psoriasis improved on both regimens.