Objective: To assess whether increment of vitamin D daily intake results in improved serum 25 (OH) vitamin D levels and reduced respiratory morbidity in premature infants.
Methods: A randomized double-blind clinical pilot trial, including preterm infants born at 32+6 to 36+6 weeks of gestation. The control group received 400 IU of cholecalciferol daily compared to 800 IU daily in the intervention group. Levels of 25 (OH) vitamin D were measured at birth, 6 and 12 months of age. Respiratory morbidity was followed until 1 year of age.
Results: Fifty subjects were recruited during the study period; the median measured 25 (OH) vitamin D levels in the control vs. intervention groups were: 26.5 vs. 34 nmol/L (p-value 0.271) at birth, 99 vs. 75.5 nmol/L (p-value 0.008) at 6 months and 72.5 vs. 75 nmol/L (p-value 0.95) at 12 months of age. Infants with insufficient vitamin D (< 75 nmol/L) levels had higher respiratory morbidity. Serum vitamin 25 (OH) D is a fair predictor for respiratory symptoms (AUC 0.697, 95%CI 0.509-0.885, p-value 0.047) and for recorded acute respiratory illnesses (AUC 0.745, 95%CI 0.569-0.922, p-value 0.012).
Conclusion: Doubling the daily intake of vitamin D in premature infants did not increase serum 25 (OH) vitamin D level, due to poor compliance in the intervention group. We found an inverse association between serum 25 (OH) vitamin D and respiratory symptoms, indicating vitamin D deficiency is a fair predictor for respiratory morbidity. This article is protected by copyright. All rights reserved.