Indirect estimates of body composition are useful for groups but unreliable in individuals
Indirect estimates of body composition are useful for groups but unreliable in individuals
复制标题
DOI：
10.1038/sj.ijo.0801387
复制
发表时间：
2000-09-01
影响因子：
4.9
通讯作者：
O'Dea, K
中科院分区：
文献类型：
--
作者：
Piers, LS;Soares, MJ;O'Dea, K
目的：评估体重指数（BMI）在基于氘稀释法（BF%（DD））获得的体脂百分比（BF%）估计值识别超重或肥胖个体方面的有用性。此外，为了评估生物电阻抗分析（BIA）和皮褶厚度（SFT）测量的准确性，在估计澳大利亚人的身体组成在个人和群体水平。设计：横断面研究。对象：117名健康的澳大利亚志愿者的欧洲血统，包括51名男性和66名女性，年龄从19岁到77岁。测量：BMI根据体重和身高计算。使用氘稀释法（FFMDD）从总身体水分（TBW）的测量值估计无脂肪质量（FFM）。使用Durnin和Womersley方程的SFT（Br J Nutr 1974; 32：77 - 97）（FFMSFT），和BIA使用Luhaski等人的方程（J Appl Physiol 1986; 60：1327 - 1332）（FFMLU），Segal等人（Am J Clin Nutr 1988; 47：7 - 14）（FFMSe）和Heitmann（Eur J Clin Nutr 1990; 44：831 - 837）（FFMHe）。估计的脂肪量（FM）的计算体重和FFM之间的差异，而BF%的计算表示FM作为体重的百分比。结果：BMI有不良的敏感性和阳性预测值，确定个人超重/肥胖的BF%（DD）分类。此外，BIA或SFT的FFM（以及FM）估计值不能与DD互换使用，否则在个人层面上会有相当大的误差风险。在组水平上，误差相对较小，但具有统计学意义。虽然FFMSFT可以通过增加偏倚（雄性为1.2 kg，雌性为0.8 kg）进行校正，但对于所使用的任何方程，FFM的BIA估计值都不可能进行简单校正。然而，在男性和女性中，FFMHe、二头肌SFT和上臂中围的组合可以准确预测FFMDD。这种预测的偏差很小（< 0.15 kg），在两种性别中均无统计学显著性，并且与通过两种方法获得的平均FFM无关。海特曼的估计FFM在这项研究中描述的人体测量变量的修订有最好的灵敏度（79%），特异性（96%）和阳性预测值（92%），在确定超重/肥胖的个人相比，其他equations tested.CONCLUSION：BMI是一个穷人的替代体脂肪在男性和女性。目前推荐的公式预测的身体成分从SFT和BIA提供不准确的估计FFM无论是在个人和群体水平相比，从DD的估计。然而，海特曼的方程，当结合测量二头肌SFT和中臂周长，提供更好的估计FFM在个人和组的水平。
OBJECTIVE: To assess the usefulness of the body mass index (BMI) in identifying individuals classified as overweight or obese based on estimates of body fat percentage (BF%) obtained by the deuterium dilution (BF%(DD)) method. In addition, to assess the accuracy of bioelectrical impedance analysis (BIA) and skinfold thickness (SFT) measurements in the estimation of body composition of Australians at the individual and group level.DESIGN: Cross-sectional study.SUBJECTS: One hundred and seventeen healthy Australian volunteers of European descent, comprising of 51 males and 66 females, ranging in age from 19 to 77 y.MEASUREMENTS: BMI was calculated from body weight and height. Fat-free mass (FFM) was estimated from measures of total body water (TBW) using deuterium dilution (FFMDD). SFT using the equations of Durnin and Womersley (Br J Nutr 1974; 32: 77 - 97) (FFMSFT), and BIA using the equations of Luhaski at al (J Appl Physiol 1986; 60: 1327 - 1332) (FFMLU), Segal et al (Am J Clin Nutr 1988; 47: 7 - 14) (FFMSe) and Heitmann (Eur J Clin Nutr 1990; 44: 831 - 837) (FFMHe). Estimates of fat mass (FM) were calculated as the difference between body weight and FFM, while BF% was calculated by expressing FM as a percentage of body weight.RESULTS: BMI had poor sensitivity and positive predictive value in identifying individuals as being overweight/obese as classified by BF%(DD). Furthermore, estimates of FFM (and hence FM) from BIA or SFT could not be used interchangeably with DD, without the risk of considerable error at the individual level. At the group level errors were relatively smaller, though statistically significant. While FFMSFT could be corrected by the addition of the bias (1.2 kg in males and 0.8 kg in females), no simple correction was possible with BIA estimates of FFM for any of the equations used. However, an accurate prediction of FFMDD was possible from the combination of FFMHe, biceps SFT and mid-arm circumference in both males and females. The bias of this prediction was small ( < 0.15 kg), statistically non-significant in both sexes, and unrelated to the mean FFM obtained by the two methods. The revision of Heitmann's estimate of FFM using anthropometric variables described in this study had the best sensitivity (79%), specificity (96%) and positive predictive value (92%) in identifying overweight/obese individuals in comparison to the other equations tested.CONCLUSION: BMI was a poor surrogate for body fatness in both males and females. The currently recommended equations for the prediction of body composition from SFT and BIA provided inaccurate estimates of FFM both at the individual and group level as compared to estimates from DD. However, Heitmann's equations, when combined with measures of the biceps SFT and mid-arm circumference, provided better estimates of FFM both at the individual and group level.