Direct infant UV light exposure is associated with eczema and immune development.

Rueter K, Jones AP, Siafarikas A, Lim EM, Bear N, Noakes PS, Prescott SL, Palmer DJ.

The Journal of allergy and clinical immunology · 2019

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Abstract

Background Suboptimal vitamin D levels during critical periods of immune development have emerged as an explanation for higher rates of allergic diseases associated with industrialization and residing at higher latitudes. Objective We sought to determine the effects of early postnatal vitamin D supplementation on infant eczema and immune development. Methods By using a double-blind randomized controlled trial, newborn infants were randomized to receive vitamin D supplementation (400 IU/d) or a placebo until 6 months of age. Some infants also wore personal UV dosimeters to measure direct UV light (290-380 nm) exposure. Infant vitamin D levels were measured at 3 and 6 months of age. Eczema, wheeze, and immune function outcomes were assessed at 6 months of age. Results At 3 (P 2 ; interquartile range, 322-1210 J/m 2 ]) compared with those without eczema (median, 998 J/m 2 [interquartile range, 676-1577 J/m 2 ]; P = .02). UV light exposure was also inversely correlated with IL-2, GM-CSF, and eotaxin production to Toll-like receptor ligands. Conclusion This study is the first to demonstrate an association between greater direct UV light exposures in early infancy with lower incidence of eczema and proinflammatory immune markers by 6 months of age. Our findings indicate that UV light exposure appears more beneficial than vitamin D supplementation as an allergy prevention strategy in early life.