双能X线吸收法与生物电阻抗法测量儿童身体成分结果比较

Comparison Between Bioelectrical Impedance Analysis and Dual Energy X-ray Absorptiometry in Chidren's Body Composition Measurement

目的比较儿童双能X线吸收法与生物电阻抗法身体成分结果，为儿童体成分研究提供方法学基础。方法选择7～15岁体重正常儿童180名，每性别、年龄组约10名，分别采用DEXA和BIA测定身体脂肪组织和非脂肪组织成分及骨矿含量，分析2种方法测量结果的相关性和一致性。结果7-15岁儿童肌肉组织、骨矿含量，脂肪组织和脂肪百分比BIA与DEXA测量结果的相关系数，除个别年龄段的个别指标外，均有统计学意义（P值均〈0．05）；各年龄组女生脂肪组织和脂肪百分比测量值相关系数均高于男生。BIA与DEXA脂肪百分比测量结果的平均差值随年龄增长而降低，但男生差值标准差随年龄增长而增加，女生相对稳定。Bland—Ahman图分析男生BIA与DEXA脂肪百分比结果的一致性限男生为-7．6％-12．6％，女生为-3．2％-10．4％。男、女生BIA得出的非脂肪组织指数（FFMI）大于DEXA结果，差值在2．0以内，男生有随脂肪百分比含量升高而增加的趋势；女生20％-30％脂肪百分比组差值最小。结论儿童BIA与DEXA身体成分测量值相关性好。BIA与DEXA相比，可低估脂肪组织含量和脂肪百分比，高估肌肉组织含量和骨矿含量。

Objective To compare Bioeleetrieal Impedance Analysis （BIA） and Dual Energy X-ray Absorptiometry （DEXA） measurement in body compositien of normal-weight children aged 7 - 15 years old, and to provide bases for the research of children＇ s body composition Methods For each gender and age group from 7 to 15 years old, about 10 normal-weight children （ 180 totally） were seleoted to receive body composition measurement by both BIA and DEXA. Correlation and agreement of the two metheds were analyzed. Results Most correlation eoeffieients of BIA and DEXA measurement in muscle, bone minend content, fat and body fat percentage were statistically significant（ P 〈 0.05）. The correlation coefficients for female fat tissue and body fat percentage were higher than those of male. The difference in fat percentage between BIA and DEXA decreased with age, but the standard deviation of bey＇s increased with age while the girl＇ s was comparatively stable. Bland-Altman plot analysis showed that the agreement limit for body fat percentage between BIA and DEXA was from - 7.6% to 12.6% and from - 3.2% to 10.4% respectively. Fat-free mass indices obtained by BIA were higher than DEXA for both boys and girls and the differences were less than 2.0. Boy＇s differences in body fat percentage tended to increase with age and the difference of 20% - 30% fat pereentage group was the least for girl. Conclusion The correlatien between BIA and DEXA in body composition measurement is good for children aged 7- 15 years old. BIA will undetestimste the fat mass and body fat percentage and overestimate muscle mass and bone mineral content.