Effect of phototherapy on plasma 25(OH)-vitamin D in neonates.

The possibility that phototherapy may increase plasma levels of 25(OH)-vitamin D was assessed by measuring levels before and after 48 h continuous phototherapy using a standard phototherapy unit (Vickers, Basingstoke , England). There was no significant increase in plasma 25(OH)-vitamin D after 48 h phototherapy and it is concluded that such treatment does not stimulate photobiosynthesis of vitamin D.