Is Higher 25-hydroxyvitamin D Level Preventive for Respiratory Distress Syndrome in Preterm Infants?

Objective: The objective of this study was to investigate the relationship between cord blood 25-hydroxyvitamin D (25(OH)D) levels and respiratory distress syndrome (RDS) development in preterm infants.

Study Design: Between January 2012 and January 2013, 81 preterm infants, gestational age below 32 weeks, were prospectively enrolled into the study. Cord bloods of these newborns were tested for 25(OH)D levels. Low level was defined as ≤ 15 ng/mL (Group 1) and normal level as > 15 ng/mL (Group 2). Patients in Group 1 were also divided further into two subgroups as severe deficiency (Group 1a, ≤ 5 ng/mL) and mild deficiency (Group 1b, 5-15 ng/mL).

Results: In this study, 57 infants had low 25(OH)D levels (Group 1, median 8.0 ng/mL [interquartile range, IQR, 5-10]; Group 2, median 21 ng/mL [IQR, 19-24.7]). RDS rate was significantly higher in Group 1a (n = 18, 32.7%) and Group 1b (n = 34, 61.8%) compared with Group 2 (n = 3, 5.4%) (p = 0.001). There were no difference of having RDS between Group 1a (94.7%) and Group1b (89.5) (p = 0.512). Multivariate analysis showed that higher 25(OH)D level can be preventive for the development of RDS (odds ratio, 0.6; 95% confidence interval (0.5-0.8); p = 0.001).

Conclusion: Lower cord blood 25(OH)D levels might be associated with increased risk of RDS in preterm infants with very low birth weight.