Vitamin D Status in Chronic Kidney Disease – UVB Irradiation Is Superior to Oral Supplementation

Abstract In chronic kidney disease (CKD) a deficiency of 1,25-dihydroxyvitamin D is common. The aim of this review was to compare vitamin D status after oral supplementation of vitamin D3 to that of serial suberythemal irradiation in end-stage kidney disease (ESKD) patients. Ninety-five patients, with a mean age of 62 (range=35-82) years, were treated with a mean dose of 35,000 (20,000-60,000) IU vitamin D3 per week for a period of 18 months. Fourteen patients, with a mean age of 51 (range=41-57) years, were whole-body UVB irradiated for over 6 months. From 3 hemodialysis patients skin biopsies were performed. With oral supplementation 25(OH)D3 increased by 60%. With UV irradiation 25(OH)D3 increased by 400%. Gene expression analysis demonstrated an improvement in the vitamin D receptor (VDR) by 0.65 fold, in 1-alpha-hydroxylase (CYP27B1) by 1.0 fold, and in 25-hydroxylase (CYP2R) by 1.2 fold. Serial suberythemal UVB irradiation of patients with CKD on dialysis is capable to improve serum 25(OH)D3 and 1,25(OH)2D3 by enhancing the skin's ability to activate vitamin D.