西安市某小学校学生身体成分的生物电阻抗分析调查研究

Study on body composition of students in one primary school in Xi'an by bioelectrical impedance analysis

目的了解西安市某小学校学生的身体成分特征,并阐明性别和年龄因素对学生身体成分的影响。方法2021年9月26日至9月30日,采取横断面调查研究方法,选取西安市某小学校一年级至六年级共计1133名小学生为研究对象,其中男生594名、女生539名,将其分为6~岁、7~岁、8~岁、9~岁、10~岁、11~岁6个年龄组,应用生物电阻抗分析技术测量其身体成分,并对结果进行统计分析。结果6~岁、8~岁年龄组男生身高均高于同龄女生(t值分别为2.687、3.691);7~岁、8~岁、9~岁和11~岁年龄组男生体质量均高于同龄女生(t值分别为2.384、4.187、3.073、2.337);除外10~岁组,其余5个年龄组男生身体水分(TBW)、细胞内水(ICW)、细胞外水(ECW)和蛋白质含量均高于同龄女生(TBW:t值分别为3.780、4.150、6.134、3.372、1.983,ICW:t值分别为3.720、4.213、6.178、3.585、2.114,ECW:t值分别为3.858、4.029、6.026、3.019、1.560,蛋白质:t值分别为3.589、4.289、6.184、3.669、2.208);6~岁、7~岁、8~岁、9~岁年龄组男生体内无机盐含量均高于同龄女生(t值分别为2.908、2.076、4.276、1.989);8~岁、9~岁、10岁、11~岁年龄组男生身体脂肪含量(BFM)均高于同龄女生(t值分别为2.611、2.460、2.045、2.314);6~岁组男生体脂率(PBF)低于同龄女生(t=-2.689);除外10~岁组,其余5个年龄组男生骨骼肌含量(SMM)、去脂体质量(FFM)和身体细胞量(BCM)均高于同龄女生(SMM:t值分别为3.752、4.223、6.202、3.568、2.145,FFM:t值分别为3.739、4.057、6.083、3.345、1.951,BCM:t值分别为3.651、4.220、6.192、3.558、2.133);7~岁、8~岁、9~岁和11~岁年龄组男生50kHz全身相位角(PA)均高于同龄女生(t值分别为4.422、4.573、5.345、4.045),差异均有统计学意义(P<0.05)。7~岁、8~岁、9~岁和11~岁年龄组男生体质量指数(BMI)均高于同龄女生(t值分别为2.551、3.675、3.629、2.906);8~岁、9~岁、10~岁、11~岁年龄组男生体脂肪质量指数(FMI)均高于同龄女生(t值分别为2.205、2.418、1.976、2.453);除外10~岁组,其余5个年龄组男生去脂体质量指数(FFMI)和四肢骨骼肌质量指数(SMI)均高于同龄女生(FFMI:t值分别为3.785、6.592、6.993、5.804、3.051,SMI:t值分别为3.341、6.287、7.134、5.211、2.981),差异均有统计学意义(P<0.05)。随着年龄的增加,男生和女生的身高、体质量、BFM、FFM、FFMI、SMM及SMI总体均呈增长趋势(男生:χ^(2)值分别为408.668、264.335、113.488、359.837、105.788、351.220、191.825;女生:χ^(2)值分别为335.645、212.745、79.769、280.594、72.775、271.408,F=45.892),但男生和女生的FMI均在10岁达到峰值后开始下降(男生:χ^(2)=38.041;女生:F=2.753),差异均有统计学意义(P<0.05)。结论除10~岁外,该校小学生的身体成分均具有显著性别差异特征,而且男生和女生的主要身体成分参数大都随着年龄增加而增长。

Objective To explore the body composition characteristics of students in one primary school in Xi'an,and to clarify the influences of gender and age on body composition of students.Methods A total of 1133 primary school students from grade one to six were selected as the study subjects in the cross-sectional study from September 26 to 30,2021,including 594 boys and 539 girls.They were divided into six age groups,including 6-years old,7-years old,8-years old,9-years old,10-years old and 11-years old groups.Body composition was measured by bioelectrical impedance analysis method,and the results were analyzed.Results Height of boys in 6-years old and 8-years old groups were significantly higher than that of girls(t=2.687 and 3.691,respectively).In 7-years old,8-years old,9-years old and 11-years old groups,weight of boys was significantly higher than that of girls(t=2.384,4.187,3.073 and 2.337,respectively).Except for the 10-years old group,the total body water(TBW),intracellular water(ICW),extracellular water(ECW)and protein levels of boys in other five groups were significantly higher than those of girls(TBW:t=3.780,4.150,6.134,3.372 and 1.983,respectively;ICW:t=3.720,4.213,6.178,3.585 and 2.114,respectively;ECW:t=3.858,4.029,6.026,3.019 and 1.560,respectively;protein:t=3.589,4.289,6.184,3.669 and 2.208,respectively).The inorganic salt of boys in 6-years old,7-years old,8-years old and 9-years old groups were higher than that of girls(t=2.908,2.076,4.276 and 1.989,respectively).The body fat mass(BFM)of boys in 8-years old,9-years old,10-years old and 11-years old groups were higher than that of girls(t=2.611,2.460,2.045 and 2.314,respectively).The percent body fat(PBF)of boys in 6-years old group was higher than that of girls(t=-2.689).Except for the 10-years old group,the skeletal muscle mass(SMM),fat free mass(FFM)and body cell mass(BCM)of boys in other five groups were significantly higher than those of girls(SMM:t=3.752,4.223,6.202,3.568 and 2.145,respectively;FFM:t=3.739,4.057,6.083,3.345 and 1.951,respectively;BCM:t=3.651,4.220,6.192,3.558 and 2.133,respectively).The 50kHz phase angle(PA)of boys in 7-years old,8-years old,9-years old and 11-years old groups were higher than that of girls(t=4.422,4.573,5.345 and 4.045,respectively),and the differences were statistically significant(P<0.05).The body mass index(BMI)of boys in 7-years old,8-years old,9-years old and 11-years old groups were higher than that of girls(t=2.551,3.675,3.629 and 2.906,respectively).The fat mass index(FMI)of boys in 8-years old,9-years old,10-years old and 11-years old groups were higher than that of girls(t=2.205,2.418,1.976 and 2.453,respectively).Except for the 10-years old group,the fat free mass index(FFMI)and skeletal muscle mass index(SMI)of boys in other five groups were significantly higher than those of girls(FFMI:t=3.785,6.592,6.993,5.804 and 3.051,respectively;SMI:t=3.341,6.287,7.134,5.211 and 2.981,respectively),and the differences were statistically significant(P<0.05).The height,weight,BFM,FFM,FFMI,SMM and SMI of boys and girls increased with age(boys:χ^(2)=408.668,264.335,113.488,359.837,105.788,351.220 and 191.825,respectively;girls:χ^(2)=335.645,212.745,79.769,280.594,72.775 and 271.408,respectively,F=45.892),while FMI in both boys and girls peaked at age 10 and then began to decline(boys:χ^(2)=38.041;girls:F=2.753,P<0.05),and the differences were statistically significant(P<o.05).Conclusion Significant gender differences of body composition are found in primary school students except for 10-years old group,and body composition of both boys and girls increase with age.