NHANES Data Portray Potential Link Between Psoriasis Severity, Vitamin D

An analysis of nearly 500 patients with psoriasis gleaned from the National Health and Nutrition Examination Survey (NHANES) revealed a linear relationship between lower vitamin D levels, as measured through blood tests, and increasing psoriasis severity. The results suggest that vitamin D supplements, which are available without a prescription, could benefit patients with psoriasis.¹

A research team identified 491 psoriasis cases from the 40,401 patients in NHANES surveys between 2003 and 2006 (n = 162 cases) and 2011 through 2014 (n = 329 cases). Investigators also collected data on 25-hydroxyvitamin D (25[OH]D] levels, self-reported psoriasis-affected body surface area (BSA), and the demographics of age, gender, race, body mass index, and smoking status. For their analysis, they defined vitamin D deficiency as “serum 25(OH)D 10 hand palms affected.”

“With growing public interest in vitamin supplementation, we wanted to further examine the connection between vitamin D levels and psoriasis severity,” said lead investigator Eunyoung Cho, ScD, associate professor in the Department of Dermatology at the Warren Alpert Medical School of Brown University, in a statement.² Cho studies the role of nutrition and environmental factors in skin cancer and inflammatory skin diseases, including psoriasis. “Few studies have looked for this association in groups of people, especially in large US populations, or examined this relationship through a clinical nutrition lens.”

The most severe psoriasis was associated with the lowest blood levels of vitamin D (56 nmol/L) and the greatest affected BSA, while patients with less severe symptoms were shown to have the highest mean vitamin D levels (67 nmol/L; P trend = .03) and less BSA affected. The relationship between vitamin D deficiency and BSA was considered statistically significant (P = .03).

Approximately 8 million people in the United States are living with psoriasis, a chronic immune-mediated inflammatory skin disease that causes skin cells to form itchy, dry patches. Nutritional research has established “significant associations between low vitamin D status and psoriasis” and concluded “successful treatment based on adequate dietary intake of vitamin D or oral vitamin D supplementation in psoriasis represent an unmet clinical need and the evidence of its beneficial effects remains still controversial.”³

A potential role of vitamin D is being studied in a wide range of autoimmune disorders, in addition to psoriasis. “The discovery of the vitamin D receptor in multiple immune cell lineages, such as monocytes, dendritic cells, and activated T cells credits vitamin D with a novel role in modulating immunological functions and its subsequent role in the development or prevention of autoimmune diseases,” according a review article on vitamin D and autoimmunity.

“Topical synthetic vitamin D creams are emerging as new therapies for psoriasis, but these usually require a doctor’s prescription,” said Rachel K. Lim, an MD candidate at the Warren Alpert Medical School of Brown University, who presented the findings at the recent Nutrition 2023 meeting of the American Society for Nutrition. “Our results suggest that a vitamin D-rich diet or oral vitamin D supplementation may also provide some benefit to psoriasis patients.”

Maggie L. Shaw contributed to this article.

References

1. Lim RK, Woo S, El Raheb S, Qureshi A, Cho E. Association of serum vitamin D levels and psoriasis severity: An Analysis of the US National Health and Nutrition Examination Survey. Presented at: Nutrition 2023; July 22-25, 2023; Boston, MA. Accessed Thursday, July 27, 2023.

2. Large study shows link between Vitamin D and psoriasis severity. News release. Newswise. July 17, 2023. Accessed July 27, 2023. https://www.newswise.com/faseb/large-study-shows-link-between-vitamin-d-and-psoriasis-severity/

3. Barrea L, Savanelli MC, Di Somma C, et al. Vitamin D and its role in psoriasis: an overview of the dermatologist and nutritionist. Rev Endocr Metab Disord. 2017;18(2):195-205.doi:10.1007/s11154-017-9411-6