超重肥胖小学生BMI、腰围与体脂百分比及腹部脂肪率的关系

The association between body mass index, waist circumference with body fat percent, and abdominalfat rate in overweight and obese pupils

目的研究超重肥胖小学生BMI、腰围与体脂百分比及腹部脂肪率的相关性。方法于2010年5月，采用方便抽样方法在北京市东城区抽取2所小学，以两所学校医务处4月份体检记录中符合超重肥胖标准的162名2～5年级学生为研究对象，对其进行体检，测量其体脂百分比、腹部脂肪率和内脏脂肪等级，并计算BMI。采用￡检验和秩和检验分析各指标性别问的差异；采用相关分析探索各脂肪分布指标（体脂百分比、腹部脂肪率和内脏脂肪等级）与BMI及腰围的相关性；运用单因素回归分析探索各变量对各脂肪分布指标的贡献率。结果超重肥胖小学生体脂百分比为（43．62±2．98）％，腹部脂肪率为（28．06±6．02）％，内脏脂肪等级为7．51±3．43，BMI为（23．41±2．83）kg／m^2。男生腰围、体脂百分比和腹部脂肪率分别为（78．57±7．76）cm、（42．36±2．56）％和（26．47±5．39）％，女生分别为（73．34±7．22）cm、（45．88±2．26）％和（30．92±6．07）％，差异均有统计学意义（t值分别为-4．22、8．75和4．81，P值均〈0．01）；男、女生内脏脂肪等级分别为8．86±3．42和5．09±1．70，差异有统计学意义（Z=-7．08，P〈0．01）。BMI与体脂百分比的相关性及对其方差贡献率（r=0．563，R^2=31．7％）高于腰围（r=0．402，R^2=16．1％）（P值均〈0．01），腰围与内脏脂肪等级的相关性及对其方差贡献率（r=0．723，R^2=57．3％）高于BMI（r=0．621，R^2=41．7％）（P值均〈0．01）。结论BMI对体脂百分比的相关性及预测能力优于腰同，腰围则对内脏脂肪的相关性和预测性较BMI强。

Objective To study the association between body mass index （BMI）, waist circumference （WC） with body fat percent, and abdominal fat rate in overweight and obese pupils. Methods Using convenience sampling, two primary schools of Dongcheng district in Beijing were selected in May 2010. A total of 162 overweight and obese pupils graded from 2 to 5 who met the criteria of overweight and obese were recruited based on the physical exam record of the school medical department in April. Their physical measurements were taken to measure body fat percent （PBF） , abdominal fat rate and visceral fat level and BMI was calculated. Independent-sample t test and Wilcoxon rank sum test were applied to analyze the gender differences. Correlation analysis was used to explore the association between the indexes of fat distribution （PBF, abdominal fat rate and visceral fat level） and BMI and WC. Univariate regression analysis was conducted to determine the variance of three indexes of fat distribution explained by the independent variables. Results The PBF of overweight and obese pupils was （43.62 ± 2. 98） %, the abdominal fat rate of them was （28.06 ±6.02）%,the visceral fat level of them was 7.51 ±3.43,BMI was （23.41 ± 2. 83 ） kg/m^2. WC, PBF and abdominal fat rate were （ 78.57 ± 7.76 ） cm, （ 42. 36 ± 2. 56 ） % and （ 26. 47 ± 5.39） % in boys and （ 73.34 ± 7.22 ） cm, （45.88 ± 2. 26 ） %, （ 30. 92 ± 6. 07 ） % in girls. The difference in gender was significant （ t values were - 4. 218,8. 751,4. 811, respectively, all P values 〈 0. 01 ） . Thevisceral fat level of boys and girls were 8.86 ± 3.42 and 5.09 ± 1.70, with significant difference （ Z = -7.08 ,P 〈0. 0l ）. The correlation between PBF and BMI and the variance of PBF explained by BMI （r = 0.563,R^2=31.7%） were stronger than them with WC （r =0.402,R^2 = 16. 1%） （P 〈0.01）.The correlation between visceral fat levels and WC and the variance of visceral fat level explained by WC （ r = 0. 723 ,R^2= 57. 3% ） were higher than them with BMI （ r = 0. 621, R^2= 41.7% ） （ P 〈 0. 01 ） . Conclusion The correlation and prediction ability of BMI and body fat percent were stronger than WC, while the correlation and prediction ability of WC and visceral fat were higher than BMI.