Objective: To assess whether increasing the daily intake of vitamin D will improve serum vitamin D levels and serve as primary prevention for respiratory morbidity in late premature infants
Methods: A randomized double-blinded clinical trial, including preterm infants born at 32+6 to 36+6 weeks` gestation, between May 2015 and January 2017. The control group received 400 IU of cholecalciferol daily comparing to 800 IU daily in the intervention group. We measured levels of 25 (OH) vitamin D at birth (cord blood), 6 months and 12 months and followed the respiratory morbidity in both groups.
Results: 50 subjects were recruited during the study period; 25 subjects in each group. The median 25 (OH) vitamin D levels in the control group vs the intervention group 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. Regarding their respiratory morbidity, the intervention group, which had significantly lower vitamin D levels, had 3.5 vs. 1.9 (p- value 0.073) respiratory diseases during the follow-up year. Both groups had similar rate of emergency room visits for respiratory symptoms and number of relievers` consumption.
Conclusion: Doubling the daily intake of vitamin D in the first year of life doesn`t increase its serum levels, when compared to control group. We found reversed association between serum levels of vitamin D and number of respiratory diseases in premature infants during the first year of life.
