7～17岁儿童青少年骨矿含量与骨密度变化

Analysis on the Bone Mass and Bone Mineral Density in 7-17-y-old Children and Adolescents

目的:探讨儿童青少年生长发育阶段骨矿物质沉积规律及骨密度变化的性别差异;方法:对北京市478名7～17岁健康儿童青少年,采用DEXA法测量全身及各部位身体成分,分析各年龄组骨矿含量及骨密度的变化;结果:男女生全身骨矿含量和骨密度均随年龄增长而持续增加,7～17岁男女生全身骨矿含量分别增长了1.80和1.83倍,骨密度增长约40%;男女生骨密度增长幅度最大的年龄分别为14～15岁和11～12岁。在青春期生长突增阶段,男女全身及多数部位骨密度变化曲线出现"两次交叉"现象,但12岁以后女生头部和脊柱骨密度超过男生,没有出现第二次交叉。全身骨密度与体脂率、腰围等肥胖相关指标呈负相关,与肌肉组织含量呈正相关(P=0.000);与男女生全身骨密度相关程度最高的是躯干骨密度(相关系数分别为0.911,0.909,P=0.000),其次是大腿、骨盆。结论:青春期女生骨骼生长突增早于男生;除头部、脊柱外,男女多数部位骨密度生长发育曲线出现两次交叉;儿童青少年全身骨密度与肥胖程度呈负相关,与肌肉含量呈正相关;躯干骨密度对全身骨密度有较好的预测意义。

Objectives：To explore the bone mass and bone mineral density change in children and adolescents.Methods： 478 healthy children and adolescents aged 7~17 were recruited from 5 schools located in Beijing.Their whole body and different body parts composition were measured with DEXA.Bone mass and bone mineral density were analyzed in this paper.Results： Both boys and girls follow the same course of growth for bone mass and bone mineral density,which were increased from 7 to 17 by 1.80 for boys and 1.83 times for girls and 40% for both of them.The maximum increment of bone density was in 14~15 and 11~12 for boys and girls respectively.The bone density distance curve of whole body and most of body parts between boys and girls demonstrates ＂twice intersections＂ during pubertal growth spurt period except for head and spine.Two crossovers were in 11~12 and 14~15 respectively.Whole body bone density was correlated with body fat percentage,waist circumference negatively,and correlated with muscular mass positively（P=0.000）.Among body parts,the trunk bone density was correlated with whole body bone mineral density in boys and girls（r=0.911 for boys and 0.909 for girls,respectively.P=0.000）,and then follows the thighs and pelvic.Conclusion：Skeletal growth spurt in girls was earlier than boys.Except for head and spine,the growth curves of the bone density of girls and boys have two crossovers.Excessive body fat might have a negative impact on the growth of bone mineral density.Trunk bone density might be a good predictor of whole body bone density.