Saliva for Assessment of Vitamin A status in preterm Infants

Background: Vitamin A is essential for development and growth of lungs in preterm infants. Diseases characterised by abnormal lung development such as bronchopulmonary dysplasia (BPD) may be linked to vitamin A deficiency. BPD is associated with long term breathing and developmental problems. Very preterm infants are at risk of vitamin A deficiency. Timely evaluation of vitamin A status of preterm infants may help to assess the risk of BPD and tailor vitamin A therapy based on the infant’s vitamin A status. Current method of assessment of vitamin A is “Relative Dose Response” (RDR). RDR test involves collection of two blood samples from the infant, one before and one after a dose of vitamin A. Thus, the requirement of repeated blood sampling, which is an invasive procedure and also increases risk of anaemia, is a major disadvantage of current RDR test. Therefore, a minimally invasive method with least harm is required. Aim: 1) To compare salivary vitamin A with blood vitamin A, and RDR using saliva with RDR using blood; 2) Assess safety of the test Participant group: Participants will be preterm infants admitted in King Edward Memorial Hospital, less than 30 weeks gestational age at birth and 21 to 28 days of life, and tolerating milk feeds. Project design and Methods: An informed consent will be obtained from the parents of the eligible infants. RDR test will be performed. The test involves collection of blood samples of 0.5 mL each, before and five hours after a dose of vitamin A (2000 IU/kg body weight). Along with the blood samples, samples of saliva will also be collected using proprietary swab specifically designed for infants. An additional saliva sample will be collected at seven hours, as appearance of vitamin A in saliva may lag behind its appearance in blood. Collection of saliva is a painless procedure with no expected harm to the infant. Vitamin A levels will be measured in blood and saliva samples with high performance liquid chromatography which is a standard method of vitamin A measurement. All the study infants will be monitored for 24 hours for adverse effect of vitamin A. Expected outcomes: A study in adults showed a good correlation between salivary and blood vitamin A in adults. We expect that salivary vitamin A level will correlate with blood vitamin A in preterm infants and will be useful to assess vitamin A status of preterm infant