| Objectiv:To investigate the relationship between vitamin D level and renal calcium excretion,to explore the changes of serum calcium,parathyroid hormone,alkaline phosphatase and urine calcium / creatinine when the level of 25(OH)D increased slightly,in order to judge the excess vitamin D supplement in the early stage.Methods : Children were selected from the patients who was first diagnosised in 2017-2019 at pediatrics growth and development department of Second Hospital of Hebei Medical University.Exclusion of endocrine diseases such as parathyroid and thyroid;renal diseases such as tubular acidosis,nephrotic syndrome;other congenital bone metabolism disorders;long-term braking or the use of diuretics or long-term steroid therapy,etc.Detection of serum 25(OH)D level by tandem mass spectrometry,and include vitamin D adequate children,whose serum 25(OH)D levels were between 20ng/ml and 100ng/ml(50nmol/l-250nmol/l)and divided into experimental group and control group according to the levels of vitamin D.Experimental group: 25(OH)D > 50 ng / ml,?100 ng / ml;control group: 25(OH)D >30 ng / ml,and ?50 ng / ml.The levels of serum calcium,parathyroid hormone,alkaline phosphatase,random urine calcium and urinary creatinine were measured in two groups the next morning,and the urinary calcium / creatinine ratio(mg/mg)was calculated.SPPSS 23.0 softwar are used to Statistical analysis.Results 1.The experimental group included 20 male children and 8 female children,(2.07 ±2.09 years old).There were 18 male children in the control group,10 female children in the control group(3.14 ±3.06 years old).There was no statistical difference between the two groups.2.When we measured 25(OH)D levels in these two groups,and reviewed the vitamin D consumption history,we found that the children in the experimental group had vitamin D over intaked definitely.3.The effect of vitamin D on serum calcium concentration: the serum calcium concentration was 2.56 ±0.14 mmol / l in the experimental group and 2.46 ±0.12 mmol / l in the control group.The difference of blood calcium was statistically significant,but all within the normal range,compared with the control group.The experimental group did not show a significant increase in blood calcium,and did not meet the criteria of hypercalcemia.The spearman correlation coefficient between vitamin D level and serum calcium concentration was rs=0.321*,and P > 0.05,that is to say,the correlation between vitamin D and blood calcium was low and the correlation was not significent.4.Parathyroid hormone: The experimental group was 14.94 ±10.59 pg/ml and in the control group was 19.18 ±8.65.There was significant difference between the two groups.The level of PTH in the experimental group was lower but still in the normal range.There was no significant correlation between vitamin D level and spearman correlation coefficient of parathyroid hormone(rs=-0.174,).5.Alkaline phosphatase: The level of ALP was 283.11 ±58.22U/L in the experimental group and 241.64 ±64.09U/L in the control group.There was significant difference between the two groups.The level of ALP in the experimental group was significantly higher than that in the control group,but also within the normal range.The spearman correlation coefficient between vitamin D level and alkaline phosphatase was rs=-0.288*,and P < 0.05,that is to say,the correlation between vitamin D and alkaline phosphatase was low and the correlation was significant.6.Random urinary calcium / creatine(mg/mg): the ratio of random urinary calcium to creatinine in the experimental group was 0.46 ±0.27,and that in the control group was 0.008 ±0.07.there was significant difference between the two groups.The urinary Ca/Cr in the experimental group was significantly higher than that in the reference standard(mg/mg).The spearman correlation coefficient between vitamin D level and urine Ca/Cr was rs=0.781,and P < 0.001.there was a positive correlation between vitamin D level and urinary Ca/Cr,and the correlation was statistically significant.Conclusions:In this study,vitamin D levels were increased by taking vitamin supplements or inappropriate iatrogenic supplements,and all of this patients have no symptoms of vitamin D toxicity.When the vitamin D level was in 50-100ng/ml,there was a slight increase in blood calcium,a slight decrease in parathyroid hormone and a increase in serum alkaline phosphatase level,but all of these index were still within the normal rangeIt has poor significance in suggesting the state of vitamin D poisoning before poisoning.However,the random urine calcium / creatine increased significantly and exceeded the normal reference range.In the range of vitamin D sufficient,the random urinary calcium / creatine increased with the rise of vitamin D,that is say the random urinary calcium / creatine could reflect the state before vitamin D excess. |
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