The Effect of Narrowband UV-B Treatment for Psoriasis on Vitamin D Status During Wintertime in Ireland.
Arch Dermatol. 2010 Aug;146(8):836-42.
Ryan C, Moran B, McKenna MJ, Murray BF, Brady J, Collins P, Rogers S, Kirby B.
BCh, BAO, Baylor Research Institute, 3900 Junius St, Ste 125, Dallas, TX 75246. Caitriona.ryan at baylorhealth.edu.
Objectives To determine whether narrowband UV-B (NB-UV-B) may mediate its beneficial effect on psoriasis by increasing vitamin D levels, and to assess the effect of NB-UV-B on vitamin D status in patients with psoriasis in wintertime.
DESIGN: A prospective controlled study from October 2008 to February 2009.
SETTING: A dermatology outpatient department at a university teaching hospital. Patients Thirty consecutive patients with psoriasis treated with NB-UV-B and 30 control patients with psoriasis were recruited. Control patients were recruited within 1 week of treated patients to control for seasonal variation of serum 25-hydroxyvitamin D 25(OH)D levels. One patient with photoaggravated psoriasis was withdrawn from the study. Intervention Narrowband UV-B was administered 3 times per week. Main Outcome Measure Serum 25(OH)D was measured at baseline, after 4 weeks and at completion of treatment.
RESULTS: Levels of serum 25(OH)D increased significantly (P < .001) from a median (range) of 23 (9-46) ng/mL at baseline to 59 (32-112) ng/mL at the end of NB-UV-B treatment compared with no change in the control group. The change in serum 25(OH)D level correlated with the number of exposures of NB-UV-B (r = 0.61; P < .001) and cumulative UV-B dose (r = 0.47; P = .01) but not with treatment response. At the end of the study, all patients in the treatment group were vitamin D sufficient, but 75% of the control group had vitamin D insufficiency serum 25(OH)D level <20 ng/mL. In a multiple regression model, prior phototherapy was the sole predictor of baseline serum 25(OH)D level (r(2) = 0.13; P = .006), whereas the number of exposures of NB-UV-B predicted change in serum 25(OH)D level (r(2) = 0.38; P = .001).
CONCLUSIONS: Narrowband UV-B effectively increases serum 25(OH)D level while clearing psoriasis. Up to 75% of Irish patients with psoriasis were shown to be vitamin D insufficient during wintertime. PMID: 20713813