Demerath E W, Guo S S, Chumlea W C, Towne B, Roche A F, Siervogel R M
Lifespan Health Research Center, Department of Community Health, Wright State University School of Medicine, Kettering, Ohio 45420, USA.
Int J Obes Relat Metab Disord. 2002 Mar;26(3):389-97. doi: 10.1038/sj.ijo.0801898.
The purpose of the study was to compare estimates of body density and percentage body fat from air displacement plethysmography (ADP) to those from hydrodensitometry (HD) in adults and children and to provide a review of similar recent studies.
Body density and percentage body fat (% BF) were assessed by ADP and HD on the same day in 87 adults aged 18-69 y (41 males and 46 females) and 39 children aged 8-17 y (19 males and 20 females). Differences between measured and predicted thoracic gas volumes determined during the ADP procedure and the resultant effects of those differences on body composition estimates were also compared. In a subset of 50 individuals (31 adults and 19 children), reliability of ADP was measured and the relative ease or difficulty of ADP and HD were probed with a questionnaire.
The coefficient of reliability between %BF on day 1 and day 2 was 96.4 in adults and 90.1 in children, and the technical error of measurement of 1.6% in adults and 1.8% in children. Using a predicted rather than a measured thoracic gas volume did not significantly affect percentage body fat estimates in adults, but resulted in overestimates of percentage body fat in children. Mean percentage body fat from ADP was higher than percentage body fat from HD, although this was statistically significant only in adults (29.3 vs 27.7%, P<0.05). The 95% confidence interval of the between-method differences for all subjects was -7 to +9% body fat, and the root mean square error (r.m.s.e.) was approximately 4% body fat. In the subset of individuals who were asked to compare the two methods, 46 out of 50 (92%) indicated that they preferred the ADP to HD.
ADP is a reliable method of measuring body composition that subjects found preferable to underwater weighing. However, as shown here and in most other studies, there are differences in percentage body fat estimates assessed by the two methods, perhaps related to body size, age or other factors, that are sufficient to preclude ADP from being used interchangeably with underwater weighing on an individual basis.
本研究旨在比较成人和儿童通过空气置换体积描记法（ADP）和水下密度测量法（HD）得出的身体密度和体脂百分比估计值，并对近期类似研究进行综述。
在同一天，对87名年龄在18 - 69岁的成年人（41名男性和46名女性）和39名年龄在8 - 17岁的儿童（19名男性和20名女性）采用ADP和HD评估身体密度和体脂百分比（%BF）。还比较了ADP过程中测量的和预测的胸廓气体体积之间的差异，以及这些差异对身体成分估计的最终影响。在一个由50人组成的子集中（31名成年人和19名儿童），测量了ADP的可靠性，并通过问卷调查探究了ADP和HD的相对难易程度。
第1天和第2天%BF之间的可靠性系数在成年人中为96.4，在儿童中为90.1，成年人的测量技术误差为1.6%，儿童为1.8%。使用预测的而非测量得到的胸廓气体体积对成年人身体脂肪百分比估计值没有显著影响，但导致儿童身体脂肪百分比估计值偏高。ADP得出的平均体脂百分比高于HD得出的，尽管这仅在成年人中具有统计学意义（29.3%对27.7%，P<0.05）。所有受试者两种方法之间差异的95%置信区间为-7至+9%体脂，均方根误差（r.m.s.e.）约为4%体脂。在被要求比较这两种方法的个体子集中，50人中有46人（92%）表示他们更喜欢ADP而非HD。
ADP是一种可靠的身体成分测量方法，受试者认为它比水下称重更可取。然而，如此处及大多数其他研究所示，两种方法评估的体脂百分比存在差异，这可能与体型、年龄或其他因素有关，足以排除在个体层面上ADP与水下称重互换使用的可能性。
