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Summary: In the 2023 study by Jenssen et al. entitled, “Effect of Vitamin D Supplementation on Psoriasis Severity in Patients with Lower-Range Serum 25-Hydroxyvitamin D Levels: A Randomized Clinical Trial,” high-dose oral vitamin D supplementation was not found to have significant effect on psoriasis severity.1

Background and Study Results

Low serum levels of 25 hydroxyvitamin D (25(OH)D) have previously been associated with a number of dermatologic conditions including psoriasis, atopic dermatitis, vitiligo, and alopecia areata.2 Topical vitamin D analogues are used frequently as part of a treatment regimen for psoriasis, but the effects of oral vitamin D supplementation on psoriasis severity are still unclear.3 In this study from 2023, researchers in Norway conducted a randomized, double-blind controlled trial to determine the effects of oral vitamin D supplementation on psoriasis severity.

The trial included 122 participants with an initial mean Psoriasis Area Severity Index (PASI) score of 3.1 (SD 2.0) and a mean serum 25(OH)D level of 14.9 ng/mL (SD 3.9). This RCT improved upon methods used in previous trials by controlling for the effects of climate/season on disease severity by conducting the trial during the winter only and by enrolling participants with lower serum 25(OH)D levels who were more likely to benefit from intervention with supplementation. Patients in the vitamin D supplementation group received high doses of oral vitamin D (100,000 IU loading dose, then 20,000 IU weekly) for 4 months, and all participants were followed for 4 months. The primary outcome obtained was change in PASI score, and researchers also followed self-administered PASI scores, Physician Global Assessment (PGA) scores, and Dermatology Life Quality Index (DLQI) scores. By the end of the trial, there was no statistically significant difference in PASI, self-administered PASI, PGA, or DLQI scores between the supplementation group and placebo group.

Comments/Clinical Implications

In this well-designed, randomized controlled trial, oral vitamin D supplementation was found to have no statistically significant effect on psoriasis disease severity in patients with lower serum vitamin D levels. This is somewhat disappointing as a safe, inexpensive supplement that helped psoriasis severity would be a welcomed addition to the therapeutic armamentarium. Importantly, the lack of a significant effect may have been due in part to participants having a relatively low baseline disease severity index, as a slightly favorable response to vitamin D supplementation measured by DLQI was observed in participants with baseline DLQI scores greater than the median (>4). Given this primary limitation of low baseline disease severity, it cannot be determined based on this study alone what impact oral vitamin D supplementation has on psoriasis severity in patients with lower serum vitamin D levels, and thus further work in more severe patients would be useful to ascertain an effect there.

Disclosures

Aileen Park, Leo Wan, and Dr. Peter Lio report no relevant financial interests.

1. Jenssen M, Furberg AS, Jorde R, Wilsgaard T, Danielsen K. Effect of Vitamin D Supplementation on Psoriasis Severity in Patients With Lower-Range Serum 25-Hydroxyvitamin D Levels: A Randomized Clinical Trial.

2. Formisano E, Proietti E, Borgarelli C, Pisciotta L. Psoriasis and Vitamin D: A Systematic Review and Meta-Analysis.

3. Armstrong AW, Read C. Pathophysiology, Clinical Presentation, and Treatment of Psoriasis: A Review.