Is vitamin D level associated with the natural course of atopic dermatitis?

Atopic dermatitis (AD) is a chronic inflammatory disease of the skin. Apart from its well-known role on calcium metabolism, vitamin D is reported to affect skin functions. The study aims were to: compare the vitamin D levels of children with AD and healthy children; investigate the relationship between the severity of AD and vitamin D levels; and investigate the effect of vitamin D on the natural course of AD.

Sixty-nine patients with AD were enrolled. Seventy healthy children were assigned as control group. Clinical and demographic features of groups were recorded. The skin prick test, eosinophil counts, immunoglobulin (Ig) E levels and serum 25 OH cholecalciferol (25OHD3) levels were measured. After at least 4 years of follow-up, patients were re-evaluated for natural course of AD.

Mean 25OHD3 level was lower in patient group vs. control group; 19.86±6.7ng/mL (min-max: 6.8-40) vs. 24.07±9.08ng/mL, respectively, (p=0.002). Mean 25OHD3 levels, and vitamin D status were significantly different between AD severity groups. (p<0.05). In terms of vitamin D status in the pairwise comparison, vitamin D deficiency was greater in children with severe and moderate AD groups (respectively, p=0.005, p=0.018). In Tukey's post hoc analysis for 25OHD3 level, the 25OHD3 levels of severe AD are significantly lower than mild or moderate AD (respectively, p=0.001, p=0.026). There was a negative correlation between 25OHD3 levels and severity of AD (r=-0.480; p=0.001). In patients reassessed after 4 years: age, the age of AD onset, vitamin D deficiency, SCORAD level and severe AD were higher in the persistent group vs. remission group, 25OHD3 levels were higher in the remission group vs. persistent group (p<0.05).

Mean vitamin D levels were lower in patients with AD. A negative correlation between vitamin D levels and disease severity was documented. Vitamin D may affect the natural course of atopic dermatitis. There is a need for more comprehensive studies in this regard.