OBJECTIVETo investigate the relationship between serum 25-hydroxyvitamin D [25(OH)D] levels at birth and respiratory distress syndrome (RDS) in preterm infants.

METHODSThis retrospective study recruited preterm infants with gestational age of below 34 weeks who were born between January 2014 and December 2016. These preterm infants were divided into two groups: RDS (n=72) and control (n=40). Clinical data of the two groups were collected, including gestational age, birth weight, gender, delivery mode, Apgar scores at 1 minute and 5 minutes, incidence of maternal gestational diabetes mellitus, and use of prenatal steroid hormone. Peripheral blood samples were collected and 25(OH)D levels were measured by chemiluminescence immunoassay. The association between serum 25(OH)D levels at birth and RDS was analyzed by multivariate logistic regression.

RESULTSApgar scores at 1 minute and 5 minutes and serum 25(OH)D levels in the RDS group were significantly lower than those in the control group (P<0.05), while the rates of neonatal asphyxia and vitamin D deficiency were significantly higher than those in the control group (P<0.05). Multivariate logistic regression analysis showed that neonatal asphyxia (OR=2.633, 95%CI: 1.139-6.085) and vitamin D deficiency (OR=4.064, 95%CI: 1.625-10.165) were risk factors for RDS in preterm infants.

CONCLUSIONSVitamin D deficiency might be associated with increased risk of RDS in preterm infants. Reasonable vitamin D supplementation during pregnancy might reduce the incidence of RDS in preterm infants.