Abstract: Objective To investigate the serum 25-hydroxyvitamin D[(25-(OH)D]in children aged 2~6 years in urban of Xi′an in summer, and to analyze related factors, in order to strengthen attention of late vitamin D(VD) deficiency and insufficiency. Methods A total of 615 children who took physical examination in Xi′an Maternal and Child Health Hospital from July to September 2017 were enrolled in this study.Self-designed questionnaires were filled out by parents under informed consents.3 ml of limosis vein blood was collected and the serum VD was measured by liquid chromatography tandem mass spectrometer made in Co.AB,USA(API4000).Finally 471 questionnaires were received. Results The average level of 25-(OH)D in 615 children was (32.81±7.93) ng/ml.The rate of abnormal VD level(including VD deficiency and VD insufficiency) was 38.9% (239/615), which was statistically higher than that of southern China(χ²=14.65,P＜0.001),but was not significantly different from those of Toronto, Canada and northern China(χ²=1.79,2.45,P＞0.05).The rate of VD deficiency was statistically lower than that of South Carolina, US(χ²=14.2,P＜0.001).There was no significant differences on outdoor time among VD deficiency group, VD insufficiency group, VD sufficiency group and desired level of VD group(F=0.784,P=0.503).Children in desired level of VD group took VD more frequently than other three groups(P＜0.001). Conclusions VD is at low level of normal interval in children aged 2-6 years in urban area of Xi′an in summer, and VD deficiency and insufficiency is common in such population.So proper outdoor time and VD supplementation will help to facilitate children′s growth.

Key words: 25-hydroxyvita D, vitamin D insufficiency and deficiency, vitamin D supplementation, sunlight explosion, children

摘要： 目的 调查西安城区2~6岁儿童夏季血清25羟维生素D[25(OH)D]水平状况以及相关影响因素,以加强人们对晚发性维生素D(VD)缺乏和不足的重视。方法 以西安城区2017年7-9月在西安市妇幼保健院入托体检的615名儿童为研究对象,在知情同意的情况下由家长填写自编问卷。对所有儿童进行内科检查并采集空腹静脉血3 ml,使用美国AB公司液相色谱串联质谱仪(API4000)进行血清VD检测,收回问卷471份。结果 615名儿童血清VD水平为(32.81±7.93) ng/ml,VD异常率(VD缺乏和不足的总发生率)为38.9%(239/615),高于中国南方城市(χ²＝14.65,P<0.001),而与加拿大多伦多和中国北方城市比较差异无统计学意义(χ²＝1.79,2.45, P>0.05);VD缺乏率低于美国南卡罗莱纳(χ²＝14.2,P<0.001)。不同VD水平组(缺乏组,不足组,充足组和理想组)比较,各组户外活动时间差异无统计学意义(F＝0.784,P＝0.503),理想组的VD补充频次显著高于其他三组(P<0.01)。结论 西安城区2~6岁儿童夏季血清VD处于正常低水平,VD缺乏和不足率较高,合理的户外活动和VD补充有益于儿童健康生长。

关键词: 25羟维生素D, 维生素D缺乏和不足, 维生素D补充, 阳光暴露, 儿童