Ultraviolet B radiation improves serum levels of vitamin D in patients with cystic fibrosis

Background: Ultraviolet B (UVB) radiation can be used in the prevention and treatment of vitamin D deficiency. Aim: To investigate, in a controlled study of patients with cystic fibrosis (CF), whether regular UVB radiation would improve serum levels of calcidiol during the dark season (October-April). Methods: Thirty patients with mild to moderate disease were included (aged 9-40 y). All patients had cholecalciferol supplementation. One group (15 patients) was given UVB one to three times a week for 6 mo and one group (15 sex- and age-matched patients) served as controls. The radiation source consisted of three TL 12/40W UVB fluorescent lamps. Initial treatment duration was 1 min, subsequently increased by 0.5-1 min/treatment to a maximum of 10 min. Results: The mean initial serum calcidiol levels were 21 ng/ml in the controls and 22 ng/ml in the intervention group. Serum calcidiol levels increased to 44 ng/ml after 8 wk and to 50 ng/ml after 24 wk of UVB radiation; the corresponding serum levels in the controls were 19 and 25 ng/ml, respectively. The mean serum calcitriol levels increased in the treated group and were unaltered in the control group. Conclusions: UVB radiation was effective in increasing vitamin D levels in patients with CF. The study results imply that UVB radiation is valuable in chronic conditions associated with vitamin D deficiency.