北京市怀柔区儿童维生素D营养状况及其与体成分的关系

Body vitamin D content and its relationship with body composition of children in Huairou district of Beijing

目的分析儿童维生素D的营养状况及其与体成分的关系。方法选取北京市怀柔区（北纬40．3°）7～11岁学龄儿童381名，于2008年3月采集静脉血并采用酶联免疫吸附试验（ELISA，英国IDS公司）测定血清中25-羟维生素D[25（0H）D]的浓度，双能X线吸收仪（DExA，美国Norland公司）测定前臂及全身的体成分，分析维生素D与体成分的相关性。结果研究对象血清25（OH）D的平均浓度为（44．4±12．5）nmol／L，维生素D缺乏和不足率[血清25（OH）D≤50nmol／L]达68．5％。男生血清25（OH）D浓度（46．3±13．3）nmol／L高于女生（42．0±11．1）nmol／L，差异有统计学意义（t=3．38，P〈0．01）。血清25（OH）D浓度与前臂近端、远端、全身及分部位中四肢的瘦体重呈正相关（r=0．13～0．19，P〈0．05），与前臂近端、远端的体脂百分比呈负相关（r=-0．14，P〈0．05；r=-0．1]，P〈0．05），均有统计学意义。调整年龄、性别、身高、体重等混杂因素后，与前臂近端、全身分部位中双下肢的瘦体重相关性仍有统计学意义（r=0．12～0．14，P〈0．05）。血清25（OH）D浓度与各部位体脂的相关性均无统计学意义。结论维生素D缺乏在北京市郊区儿童中较为普遍，而维生素D营养状况对体成分，尤其对瘦体重有促进作用。

Objective To analyze vitamin D concentration and its association with body composition of children in Huairou district of Beijing, to provide evidence for evaluation and improvement of nutritional status of vitamin D in children. Methods Totally, 381 children aged 7-11 years were recruited in Huairou district of Beijing （40.3°N）. Samples of overnight fasting venous blood （drawn between 0630 and 0900） were obtained in late March. Serum 25-hydroxyvitamin D [25 （OH）D] concentration was determined by ELISA kits （IDS Ltd, UK）. Body composition indices of the whole body, the distal and proximal forearm were measured using dual-energy X-ray absorptiometry （DEXA,Norland,USA）. Results The average serum 25（OH） D concentration of all subjects was （44.4 ±12.5） nmol/L. The percentage of vitamin D insufficient [ serum 25 （OH） D≤ 50 nmol/L] reached as high as 68.5%（261 people）. The 25 （OH） D concentration of boys （46.3 nmol/L ±13.3 nmol/L） was significantly higher than that of girls （42.0 nmol/L ±11.1 nmol/L）, （t=3.38, P〈 0.01）. Between the serum 25 （OH）D concentration and lean body mass of proximal forearm, distal forearm, whole body, and four limbs, significant positive correlations （r=0.13-0.19,P〈0.05） were observed. After age, gender, height and weight were under controlled for, correlations between the serum 25 （OH）D concentration and lean body mass at proximal forearm, and the two lower limbs still existed （r= 0.12-0.14, P〈 0.05 ）. The serum 25 （OH） D concentration, the percentage of body fat at proximal forearm, and distal forearm were negatively correlated （r=0.14, P〈0.05; r=0.11, P〈 0.05）. However, after adjusting for confounding effects, this correlation disappeared. No significant correlation between the serum 25 （OH）D concentration and body fat was observed at any position. Conclusion Vitamin D deficiency was common in children of suburb area of Beijing. Vitamin D status was positively associated with the lean body mass.