To the Editor:

We read with great interest the article by Singh et al. (1) which provided a new idea on the effect of vitamin A in neonatal respiratory disease. Further clinical research may be needed, but some wonders exist which are as follows:

  1. 1

    Three groups were set in the article: I = control; II = surfactant; and III = surfactant + vitamin A. Maybe groups II and III should be set, II = surfactant (100% activity) and III = surfactant (60% activity) + vitamin A, because the surface activity was 40% lower in group III than that in group II, and there was no significant difference of gas exchange between groups II and III. Did vitamin A have the efficacy equal to surfactant with 40% activity or what?

  2. 2

    The study should have included both preterm and term infants. Although vitamin A supplementation could be more effective on premature infants with chronic lung disease (CLD), recent research suggested that 25% of infants remain vitamin A deficient despite vitamin A supplementation (2). The persistence of biochemical vitamin A deficiency might be due to impaired vitamin A transportation. Transthyretin, a major vitamin A transport protein, has been suggested to be reduced by inflammation (3).

  3. 3

    Intramuscular administration of 5000 IU vitamin A every other day for 4 wk could decrease the incidence of CLD. How much and how often should vitamin A be supplemented to premature infants by intratracheal administration to ensure the effect?

  4. 4

    How about vitamin A supplemented together with retinoic acid? Recent study has shown that a combination of vitamin A (the nutrient) and retinoic acid (the metabolite) improved more tissue retinoid stores than either vitamin A or retinoic acid alone in infant rats (4).

In conclusion, although intramuscular administration of vitamin A has been suggested to reduce the incidence of CLD, intratracheal administration of vitamin A may provide a new way with more absorb dosage and less pain.