The clinical significance of serum 25-hydroxy vitamin D and vitamin D binding protein in premature infants with bronchopulmonary dysplasia

Abstract

Objective To study the relationship of serum 25-hydroxy vitamin D [25-(OH) D] and vitamin D binding protein (DBP) in premature infants with bronchopulmonary dysplasia (BPD) and their clinical significance. Method From March 2017 to September 2018, the premature infants with gestational age (GA)<32 weeks admitted to the neonatal department of our hospital were prospectively studied. All the premature infants were given 800 IU/d vitamin D supplement from one week after birth. Venous blood sample were collected at birth and 28 d after birth to measure 25-(OH) D and DBP levels. The infants were evaluated for BPD at 28 d after birth and then assigned into the BPD group and the non-BPD group. The differences of 25-(OH) D and DBP levels were compared. Result A total of 170 premature infants (GA 0.05). The BPD group had a lower levels of serum 25-(OH) D at birth [(27.8±5.9) nmol/L vs. (30.4±1.1) nmol/L, P<0.05]. The levels of serum 25-(OH) D in moderate/severe BPD group were significantly lower than mild BPD group [(25.3±4.9) nmol/L vs. (29.7±5.9) nmol/L, P<0.05]; 25-(OH) D in BPD group was still lower than the non-BPD group at 28 days after birth (after vitamin D supplement) [(77.5±11.7) nmol/L vs. (83.8±11.6) nmol/L, P<0.05]. Comparison of serum DBP levels between the two groups showed that, DBP at 28 d after birth in BPD group were significantly lower than the non-BPD group, and DBP in moderate/severe BPD group were significantly lower than the mild BPD group [(373.9±19.1) μg/ml vs. (391.4±23.6) μg/ml], the differences were both statistically significant (P<0.05). Multivariate analysis showed that the high serum 25-(OH)D level at birth (OR=0.827, 95%CI 0.693~0.987) was protective factors for BPD, while neonatal pneumonia (OR=4.331, 95%CI 1.269~14.784) and neonatal sepsis (OR=4.020, 95%CI 1.153~14.015) were risk factors for BPD. Conclusion The high serum 25-(OH) D level at birth in preterm infants was protective factors for BPD, while neonatal pneumonia and sepsis were the risk factors for BPD. Moreover, low serum 25-(OH) D level at birth and low serum DBP level at 28 d after birth maybe useful indicators for the severity of BPD. Key words: Vitamin D; Vitamin D-binding protein; Bronchopulmonary dysplasia; Infant, premature