Psoriasis Severity Not Affected by Vitamin D Supplementation

Vitamin D supplementation does not affect the severity of psoriasis, according to study findings published in JAMA Dermatology.

Researchers conducted a randomized clinical trial of adults aged 18 to 79 years with active plaque psoriasis (Psoriasis Area Severity Index [PASI] score, >0) and baseline 25(OH)D levels less than 24 ng/mL. The primary study was conducted during 2 winter seasons from 2017 to 2018 and 2018 to 2019. Participants were enrolled from mid-October to mid-January.

The intervention was cholecalciferol (100,000 IU loading dose, and then 20,000 IU per week) or placebo for 4 months. The group difference in change in psoriasis severity according to baseline PASI score and at 4 months was the primary endpoint.

Of the 122 total participants, 60 received vitamin D (mean age [SD], 53.3 [10.9] years; 62% men), and 62 received placebo (mean age, 54.0 [9.1] years; 63% men). A total of 120 participants completed the study (vitamin D, n=59; placebo, n=61). Baseline PASI scores were 3.2 in the vitamin D group and 2.9 in the placebo group.

In the vitamin D group, 24 participants (41.1%) had 25(OH)D levels of at least 30 ng/mL postintervention. After 4 months, the mean (SD) 25(OH)D levels were 29.7 (5.2) ng/mL in the vitamin D group and 12.0 (3.8) ng/mL in the placebo group.

No significant difference was observed in change in PASI scores between the groups (adjusted difference, 0.11; 95% CI, -0.23 to 0.45; P =.52).

Participants who received vitamin D had a 34% decrease in odds of being in the higher Physician Global Assessment (PGA) change categories (0 or 1) vs those who received placebo, although it was not significant (adjusted odds ratio, 0.66; 95% CI, 0.27-1.63; P =.37).

No significant difference occurred in overall change in self-administered PASI (adjusted difference, -0.60; 95% CI, -1.76 to 0.55; P =.30) or Dermatology Life Quality Index (DLQI) scores (adjusted difference, -0.86; 95% CI, -1.9 to 0.19; P =.11) between groups.

Among participants who had DLQI scores greater than the median (DLQI ≥4), the difference in DLQI change was significant in favor of those who received vitamin D (adjusted difference, -2.07; 95% CI, -3.67 to -0.46; P =.01).

Limitations of the study include participants’ low baseline severity scores and the lower-than-expected increase in 25(OH)D levels.

“Based on the findings of this randomized clinical trial, any large effect of vitamin D supplementation on psoriasis severity seems unlikely in those with mild disease (PASI <5),” the researchers conclude.

Disclosure: One of the study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.