Objective
To examine the association between maternal health insurance status and the development of neonatal vitamin D(VitD) deficiency.
Methods
Consecutive single-birth neonates admitted into our department between September 2014 and February 2015 were prospectively enrolled, excluding those diagnosed with severe apnea, anemia, and congenital hereditary metabolic diseases. Blood specimens were obtained within 48 h of birth. The serum 25-hydroxyvitamin D (VD) levels were tested using the isotope dilution ultra-performance liquid chromatography tandem mass spectrometry method. The diagnosis of VitD deficiency was made when the result was below 15ng/ml. The insurance status in the present study was operationally defined as two categories accordingly: (a) the advantaged insurance status which means having a government employee insurance scheme (GIS) or urban employee basic medical insurance (UEBMI), (b) the disadvantaged insurance status which includes having new rural cooperative medical scheme (NCMS) or uninsured. The association between the development of VitD deficiency and the maternal health insurance status was then examined using the multivariable logistic regression which simultaneously adjusted for several other potential associated factors of VitD deficiency such as season of birth, pre-pregnancy BMI, maternal sun exposure time, egg intakes, and VitD supplementation; and their respective odds ratios (OR) calculated.  
Results
A total of 125 neonates were enrolled, with a mean birth weight of 2697±713g and mean gestational age of 36.8±2.7 weeks. The mean serum VD level was 14.4±6.7ng/ml. 56.0% (70/125) of the neonates were diagnosed with VD deficiency. The maternal factors that were significantly associated with VitD deficiency included winter delivery, pre-pregnancy obesity, insufficient sun exposure time, insufficient egg intakes, insufficient VitD supplementation, and the disadvantaged maternal health insurance. After controlling for the other factors, the odds of having VitD deficiency in the neonates with maternal disadvantaged health insurance was 7.5 times (OR=7.5, 95% CI: 2.0 ~ 37.6) higher than that in those with maternal advantaged health insurance (Figure 1).
Conclusions
The disadvantaged maternal health insurance status is associated with the development of VitD deficiency in neonates. Potential reasons may include the relatively lower income level and inadequate health education of this maternal population. Our finding suggests the necessity of awareness of the socioeconomic context of pregnant women under VitD supplementation to prevent neonatal vitamin deficiency.