Serum 25-hydroxyvitamin D status in individuals with psoriasis in the general population

There is a dearth of data assessing serum 25-hydroxyvitamin D (25[OH]D) status in psoriasis. This population-based study in the United States evaluated 25(OH)D status in psoriasis and examined the associations between 25(OH)D and psoriasis severity. The 2003-2006 National Health and Nutrition Examination Survey was analyzed. Participants aged 20-59 years self-reported psoriasis, psoriasis body surface area (BSA), and psoriasis life impairment (PLI). Serum 25(OH)D was assessed with the DiaSorin radioimmunoassay. General linear models were used to examine the associations between psoriasis and 25(OH)D while accounting for age, gender, race/ethnicity, season, and body mass index (BMI). Among the 5,841 participants with complete data, 148 reported a psoriasis diagnosis. Mean 25(OH)D levels and deficiency prevalences (<20 and <30 ng/mL) were not different between those with and without psoriasis. Among those with psoriasis, a multivariate model showed participants with BSA >10 hand palms trended towards lower 25(OH)D compared to those with minimal BSA (-4.98 ng/mL, P = 0.07). PLI was not associated with 25(OH)D, but BMI showed an inverse association with 25(OH)D (coefficient = -0.40, P < 0.001). In summary, dermatologists may consider measures of adiposity as better screening tools for vitamin D deficiency than BSA involvement among psoriatics with mild-to-moderate disease.