Comment on Di Marco, N., Kaufman, J., Rodda, C.P. Shedding Light on Vitamin D Status and Its Complexities during Pregnancy, Infancy and Childhood: An Australian Perspective. Int. J. Environ. Res. Public Health 2019, 16 (4), 538, doi:10.3390/ijerph16040538

Screening of vitamin D and calcium concentrations in neonates of mothers at high risk of vitamin D deficiency

OBJECTIVE

The aim of this study was to determine, retrospectively, the serum 25OHD and calcium concentrations of screened neonates of mothers at high risk of 25OHD deficiency and examine whether their measurement contributes to the management of these neonates.

METHODS

Serum 25OHD and calcium concentrations from 600 samples of umbilical cord blood or venous blood collected from neonates over a 12-month period were analysed.

RESULTS

There was a high prevalence of vitamin D insufficiency (27.6%, 30-50 nmol/L) and deficiency (21.3%, < 30 nmol/L) in neonates from high-risk maternal groups. There was a statistically positive but weak correlation (ρ = 0.22, P < 0.0001) between 25OHD and serum calcium. Only 7 neonates out of 569 (1.2%) had calcium concentrations in the hypocalcaemic range; however, a significant number (47.6%) were reported to be in the hypercalcaemic range. Nearly all of these were venous samples collected in first 24 h after birth.

CONCLUSION

Vitamin D deficiency is prevalent in neonates of high-risk mothers but the risk of hypocalcaemia due to vitamin D deficiency at birth is low. Screening neonates entails blood testing which can cause distress to neonates and their parents, substantial imposition on staff and financial burden on the health care system. Vitamin D supplementation of these neonates from birth without routine screening appears more reasonable. Also, the data from this study suggest that the paediatric reference range for corrected calcium concentrations in neonates should be re-evaluated.

Association between variants in vitamin D-binding protein gene and vitamin D deficiency among pregnant women in china

Background

The prevalence of vitamin D deficiency and insufficiency is extremely high in pregnant women worldwide. However, the association between single nucleotide polymorphisms (SNPs) in vitamin D metabolic pathway genes and 25‐hydroxyvitamin D (25(OH)D) concentration among Chinese pregnant women is seldom reported. The risk of adverse neonatal outcomes due to maternal vitamin D deficiency has not been well investigated.

Methods

A total of 815 pregnant women and 407 infants were enrolled in this study. Serum 25(OH)D concentration was detected. DNA was extracted from the maternal blood for genotyping genetic SNPs in vitamin D pathway. An XGBoost model was established based on SNPs combined with external variables.

Results

Mean serum 25(OH)D level was 15.67 ± 7.98 ng/mL among the pregnant women. Seventy‐five percent of pregnant women had 25(OH)D deficiency in China. SNPs of GC (rs17467825, rs4588, rs2282679, rs2298850, and rs1155563) were significantly associated with maternal 25(OH)D concentration. The influence of variants of rs17467825, rs4588, rs2282679, and rs2298850 on maternal 25(OH)D might be modified by vitamin D supplementation and sunshine exposure. An XGBoost model was established for monitoring 25(OH)D status in pregnant women and provided clinical advice to reduce the risk of 25(OH)D deficiency. Mothers with 25(OH)D deficiency hinted a risk for macrosomia.

Conclusion

A high prevalence of vitamin D deficiency in China has been confirmed. A clinical model was established to guide pregnant women to supplement vitamin D according to genotype. Furthermore, we suggest the effect of maternal vitamin D status on the risk of macrosomia.