Vitamin D levels linked to psoriasis severity

Key takeaways:

• Patients with the greatest amount of body surface area affected by psoriasis had the lowest vitamin D levels.
• In contrast, those with the least amount of psoriasis had the highest vitamin D levels.

BOSTON — Among nearly 500 patients with psoriasis in the United States, lower vitamin D levels in blood samples were associated with increasing psoriasis severity, according to research presented at NUTRITION.

The findings support the role of vitamin D in the pathogenesis of psoriasis, Eunyoung Cho, ScD, an associate professor and director of research in the department of dermatology at the Warren Alpert Medical School of Brown University, and colleagues reported.

“While topical vitamin D analogs are already used to treat psoriasis, further research, such as large randomized clinical trials of oral vitamin D supplementation, is warranted before any firm medical recommendations are made on oral vitamin D supplementation use among psoriasis patients,” Cho told Healio. “Still, as vitamin D deficiency is common in psoriasis patients, clinicians can treat the deficiency, which may benefit psoriasis.”

For the study, Cho and colleagues examined the associations between vitamin D levels and psoriasis severity in a nationally representative sample of 40,401 U.S. adults enrolled in the National Health and Nutrition Examination Survey (NHANES) between 2003 to 2006 and 2011 to 2014.

The researchers quantified psoriasis severity as the amount of body surface area (BSA) affected by psoriasis and measured vitamin D levels through blood tests. They also collected information on covariates such as age, gender, race, BMI and smoking status.

Overall, Cho and colleagues identified 491 cases of psoriasis. After adjusting for the covariates, they reported observing a linear trend of increasing psoriasis severity with decreasing serum vitamin D levels. Patients in the lowest BSA group had the highest mean vitamin D levels (67 nmol/L), whereas those in the greatest BSA group had the lowest mean vitamin D levels (56 nmol/L; P = .03).

The researchers found a similar trend when evaluating the percentage of patients with vitamin D deficiency by BSA, with 25% of patients in the lowest BSA group vs. 39% in the highest BSA group being classified as vitamin D deficient.

“Only one previous study, published in 2013, has used NHANES data to analyze the relationship between vitamin D and psoriasis,” coauthor Rachel K. Lim, an MD candidate at the Warren Alpert Medical School of Brown University, said in a press release. “We were able to add more recent data, which more than tripled the number of psoriasis cases analyzed, making our results more up to date and statistically powerful than previously available data.”

References:

• Lim RK, et al. Association of serum vitamin D levels and psoriasis severity: An analysis of the US National Health and Nutrition Examination Survey. Presented at: NUTRITION; July 22-25, 2023; Boston.
• Large study shows link between vitamin D and psoriasis severity. https://www.eurekalert.org/news-releases/995505. Published July 25, 2023. Accessed July 25, 2023.