目的 评价 0~7 岁儿童维生素 D（VitD）营养状况及与骨密度的关系。方法 选择生长发育门诊因“生长发育缓慢、夜惊、多汗、烦躁不安”等就诊的儿童 6 838 人，采用化学发光法法测定血清 25 羟VitD [25-（OH）D] 水平，并同时应用定量超声仪进行骨密度检测。结果 研究对象血清 25-（OH）D 的水平为34±14 ng/mL，定量超声骨密度 Z 值为 -0.49±0.54。随着年龄增长，25-（OH）D 和骨密度水平逐渐降低，且 VitD缺乏、不足及骨密度不足的检出率逐渐增加（P<0.01）；VitD 缺乏、不足组的骨密度值明显低于 VitD 充足组，且骨密度不足的检出率也高于 VitD 充足组（P<0.01）。当 VitD 不足 [25-（OH）D 水平 20~29 ng/mL] 时，25-（OH）D水平和骨密度存在正性直线相关关系（P<0.01）。结论 学龄前期和学龄期儿童 VitD 不足和缺乏的现象较婴幼儿更严重。在一定范围内 VitD 水平和骨密度可能有关。

Objective To evaluate the endogenous vitamin D level and its correlation with bone mineral density（BMD) in children under 7 years old. Methods Totally 6 838 children who visited the Growth and Development Clinic due to "growth retardation, night terrors, hyperhidrosis, and dysphoria" were enrolled in the study. Serum 25-hydroxyvitamin D [25(OH)D] level was measured by chemiluminescence, whereas individual BMD was measured by quantitative ultrasound. Results Among all subjects, serum 25(OH)D level was 34±14 ng/mL, and the Z value of BMD was -0.49±0.54. With increasing age, serum 25(OH)D level and BMD decreased gradually（P<0.01), and the detection rates for vitamin D deficiency and low BMD increased gradually（P<0.01). Compared with those with sufficient vitamin D, children with vitamin D deficiency had a significantly lower BMD（P<0.01) and a significantly higher detection rate for low BMD（P<0.01). 25-(OH)D level showed a positive linear correlation with BMD in children with vitamin D deficiency（P<0.01). Conclusion Preschool and school-age children have severer vitamin D deficiency than infants.Vitamin D level may be correlated with BMD within a certain range.