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UVB increases vitamin D even if poor kidney by changing CYP27B1 genes in skin – Dec 2013

A narrow-band ultraviolet B course improves vitamin D balance and alters cutaneous CYP27A1 and CYP27B1 mRNA expression levels in haemodialysis patients supplemented with oral vitamin D.

Nephron Clin Pract. 2013;124(1-2):17-22. doi: 10.1159/000355010. Epub 2013 Sep 12.
Ala-Houhala MJ1, Vähävihu K, Snellman E, Hasan T, Kautiainen H, Karisola P, Dombrowski Y, Schauber J, Saha H, Reunala T.
Department of Dermatology, Tampere University Hospital, Tampere, Finland

Chronic kidney disease (CKD) patients on dialysis are prone to vitamin D insufficiency despite oral vitamin D supplementation. Here, we studied whether narrow-band ultraviolet B (NB-UVB) exposures improve vitamin D balance.

14 haemodialysis patients and 15 healthy subjects receiving oral cholecalciferol 20 µg daily got nine NB-UVB exposures on the entire body. Serum 25-hydroxyvitamin D (25(OH)D) was measured by radioimmunoassay. Cutaneous mRNA expression levels of CYP27A1 and CYP27B1, two enzymes required for hydroxylation of vitamin D into its active metabolite, were also measured.

The baseline serum 25(OH)D concentration was 57.6 ± 18.2 nmol/l in the CKD patients and 74.3 ± 14.8 nmol/l in the healthy subjects. The NB-UVB course increased serum 25(OH)D by 14.0 nmol/l (95% CI 8.7-19.5) and 17.0 nmol/l (CI 13.7-20.2), respectively. At baseline the CKD patients showed significantly increased CYP27B1 levels compared to the healthy subjects.

A short NB-UVB course is an efficient way to improve vitamin D balance in CKD patients on dialysis who are receiving oral vitamin D supplementation. The increased cutaneous CYP27B1 levels in the CKD patients suggest that the loss of renal activity of this enzyme is at least partially compensated for by the skin.

Copyright © 2013 S. Karger AG, Basel.Wants $38 for the PDF

PMID: 24029861

Overview and comments by VitaminDWiki

  • It appears that the two groups had been supplementing with 800 IU of vitamin D for a long time.
    VitaminDWiki finds it amazing that such a low level was used – especially with dialysis which further decreases vitamin D levels
  • Those with chronic kidney disease had lower level of vitamin D: 23 ng vs 30 ng – understandable since kidney is the primary means to activate vitamin D
  • Narrowband UVB was added, increasing levels by 5.6 ng and 6.8 ng respectively

See also VitaminDWiki