The Effects Of Different Doses Of Vitamin D Supplementation On Biochemical Indexes In Premature Infants:A Meta-analysis

Objective:The effects of daily supplementation of vitamin D with low dose(400IU)and high dose(800IU)on serum 25-hydroxyvitamin D,bone metabolism indexes such as calcium,phosphorus and alkaline phosphatase,as well as occurrence of rickets and vitamin D deficiency(<20ng/ml)were systematically evaluated.Methods:Such databases as PubMed,Embase,The Cochrane library,CNKI,WanFang Data,VIP were electronically searched systematically.The retrieval time was up to November 2018.Clinical randomized controlled trials(RCTS)of preterm infants supplemented with different doses of vitamin D were searched.The low-dose group was 400IU/d,while the high-dose group was 800IU/d.The quality of RCTs were evaluated by the Cochrane Collaboration's tool in order to assess the risk of bias.Statistical analysis was performed by Review Manager 5.3,Odds ratio(OR)and 95% confidence interval(95%CI)statistical analysis were used for counting data,and weighted mean difference(MD)OR standardized mean difference(SMD)and 95%CI statistical analysis were used formeasurement data.Results : A total of 9 references and 654 premature infants were included in the study,including 326 in the low-dose group(400 IU)and328 in the high-dose group(800IU).Meta analysis results showed that:High dose group(800IU)25 hydroxy serum vitamin D levels are significantly higher than the low dose group(400IU)[SMD=0.48,95% CI(0.73,0.24),P<0.0001],high dose group(800IU)of vitamin D deficiency events [OR=3.24,95% CI(1.39,7.57),P=0.007],rickets events [OR=2.71,95% CI(1.23,5.95),P=0.01] were significantly lower than low dose group(400IU),and the difference was statistically significant;Serum calcium levels [SMD=0.10,95% CI(-0.11,0.31),P=0.36],serum phosphorus levels[SMD=-0.12,95% CI(-0.34,0.10),P=0.28],and serum alkaline phosphatase levels [SMD=0.00,95% CI(-1.61,1.62),P=1.0] were not statistically significant.Conclusion : High dose vitamin D supplementation for premature infants can significantly improve serum vitamin D level,and the occurrence of rickets and vitamin D deficiency events was significantly reduced.Serum levels of calcium,phosphorus and alkaline phosphatase may not accurately reflect the true situation of bone metabolism in premature infants.