| ObjectivesA retrospective study was conducted to investigate the effects of different doses of vitamin D supplementation on bone metabolism,serum vitamin D levels,and growth and development indicators in preterm infants,in order to provide theoretical basis for guiding the rational use of vitamin D in preterm infants.MethodsA retrospective study was conducted to investigate the effects of different doses of vitamin D supplementation on bone metabolism,serum vitamin D levels,and growth and development indicators in preterm infants,in order to provide theoretical basis for guiding the rational use of vitamin D in preterm infants.Premature infants with gestational age<34 weeks or weight<1500 g who were admitted to the Pediatrics Department of our hospital from September 2019 to December 2021 were selected for a retrospective cohort study.They were divided into high-dose groups(total vitamin D intake ≥ 900 U/d)and low-dose groups(total vitamin D intake<900 U/d)based on different vitamin D intake doses,Bone metabolic indicators(alkaline phosphatase,serum calcium,and serum phosphorus),25 hydroxyvitamin D levels,and growth and development indicators(body weight,length,head circumference,and growth rate)were measured at the time of discharge or at the age of 28 days,and corresponding clinical data were collected.A multiple element linear regression analysis model was used to analyze the effects of different vitamin D intake levels on bone metabolism indicators,25 hydroxyvitamin D levels,and growth and development indicators.Through the ROC curve,we searched for the clinically appropriate dose of vitamin D intake,and divided the study subjects into large gestational age group(gestational age≥ 32 weeks)and small gestational age group(gestational age<32 weeks)according to different gestational ages.We analyzed the differences in bone metabolism indicators,25 hydroxyvitamin D levels,and growth and development indicators of premature infants in different gestational age groups.Results1.Effects of different doses of vitamin D supplementation on bone metabolism indicators,25-hydroxyvitamin D levels,and growth and development indicators in premature infants:A total of 229 premature infants who met the inclusion criteria were included,including 135 premature infants in the high-dose group(59.1%)and 94 premature infants in the low-dose group(40.9%).At 28 days of age or at the time of discharge,the ALP level in the high-dose group was lower than that in the low-dose group(Z=3.174,P=0.002),and the incidence of hypophosphatemia was lower than that in the low-dose group(Χ 2=6.215,P=0.045),there was no statistically significant difference in serum calcium and 25 hydroxyvitamin D levels(P>0.05).There was no significant difference between the high dose group and the low dose group in terms of birth weight,birth length,birth head circumference,weight growth rate,and body length growth rate of premature infants(P>0.05).The rate of head circumference growth ≥ 5 mm/week in the high-dose group was 74.1%,which was higher than that in the low-dose group(54.3%,Χ 2=4.036,P<0.001)。 Linear regression analysis of the effects of different vitamin D intake levels on bone metabolism indicators,serum vitamin D levels,and growth and development indicators showed that the growth rate of head circumference in the high-dose group was faster(β=1.394,95%CI:0.611～2.177,P=0.0001)。2.ROC curve analysis of the appropriate intake dose of vitamin D:The binary logistic regression analysis results of vitamin D intake dose and head circumference growth rate ≥ 5 mm/week showed that the higher the vitamin D intake dose,the faster the head circumference growth rate(OR=1.001,95% CI: 1.000,1.002).Vitamin D supplementation had a significant impact on the growth rate of head circumference(P=0.006),with an area under the curve(AUC)of 0.611(95% CI:0.535 to 0.688)affecting the growth rate of head circumference.Based on the calculation of the ROC curve,the critical value of vitamin D intake that has a significant impact on the growth rate of head circumference is 900 U/d.3.Differences in bone metabolism indicators,serum vitamin D levels,and growth and development indicators of premature infants in different gestational age groups at appropriate vitamin D supplementation doses:At an appropriate vitamin D supplementation dose(total vitamin D intake ≥ 900U/d),there was no statistically significant difference in serum calcium,alkaline phosphatase,and 25 hydroxyvitamin D levels between the large gestational age group and the small gestational age group(P>0.05).The serum phosphorus level of premature infants in the large gestational age group was higher(Z=2.175,P=0.030),but there was no statistically significant difference in the incidence of hypophosphatemia between the two groups(P>0.05).The rate of weight gain in the large gestational age group was faster(Z=2.483,P=0.013),and there was no statistically significant difference between the two groups in terms of body length growth rate and head circumference growth rate(P>0.05).The results of risk factor analysis of bone metabolism indicators,serum vitamin D levels,and growth and development indicators in preterm infants of different gestational age groups showed that the appropriate vitamin D supplementation dose had no effect on bone metabolism indicators,25 hydroxyvitamin D levels,and growth and development indicators in preterm infants of different gestational age(P>0.05).Conclusions1.Premature infants with high dose vitamin D intake have low ALP levels,lower incidence of hypophosphatemia,and faster growth rate of head circumference.2.Vitamin D supplementation has a significant impact on the growth rate of head circumference,and the critical value of vitamin D intake that has a significant impact on the growth rate of head circumference is 900 U/d.3.There were no significant differences in bone metabolism indicators,25 hydroxyvitamin D levels,and growth and development indicators among premature infants of different gestational ages at appropriate vitamin D supplementation doses. |
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