目的:探讨学龄儿童维生素D营养状况与身体肌肉量的关系。方法:研究对象来自“儿童青少年心血管与骨健康促进项目”，于2017年采用分层整群抽样的方法在北京市对15 391名6~16岁儿童开展基线调查，2019年对其进行随访调查。进行问卷调查和检测血清25（OH）D，使用生物电阻抗法测定机体肌肉量，并计算全身肌肉质量指数（MMI）。采用多因素线性回归分析维生素D营养状况与基线和随访期MMI的关系。结果:纳入分析的10 890名儿童的年龄为（11.5±3.3）岁，男童占49.6%，基线25（OH）D水平为（35.4±12.0）nmol/L，充足率为11.1%。多因素线性回归校正年龄、性别、体脂肪量、吸烟、饮酒、奶制品摄入、维生素D补充、钙剂补充、体力活动、青春期发育状态后，未观察到维生素D营养状况与基线MMI水平关联有统计学意义（n P>0.05）。而对于随访时点MMI，25（OH）D每增加10 nmol/L，其n Z值增加0.008（n P=0.058）；相比于维生素D缺乏，维生素D不足和充足的儿童分别增高0.002（n P=0.815）和0.037（n P=0.031），趋势n P=0.089。亚组分析显示，在BMI正常组中，25（OH）D每增加10 nmol/L，维生素D充足的儿童基线MMI和随访时点MMI n Z值分别增高0.019和0.014，均n P0.05). For the follow-up MMI, then Z-score increased by 0.008 (n P=0.058) for per 10 nmol/L increase in 25(OH)D, which were 0.002 (n P=0.815) and 0.037 (n P=0.031) higher in children with insufficient and adequate vitamin D than those with vitamin D deficiency, respectively (n P for trend =0.089). Subgroup analysis showed that in the normal BMI group, for per 10 nmol/L increase in 25 (OH) D, the MMI at baseline survey and MMI n Z-score at follow-up of children with adequate vitamin D and increased by 0.019 and 0.014, respectively (both n P<0.05).n Conclusions:Vitamin D nutritional status was related to muscle mass in children, and children with adequate vitamin D tended to obtain higher MMI. Children and adolescents are encouraged to maintain sufficient vitamin D levels, strengthen nutrition and exercise to promote body health.