Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, Alabama, USA.
Obesity (Silver Spring). 2011 Nov;19(11):2222-7. doi: 10.1038/oby.2011.109. Epub 2011 May 5.
Aerobic fitness and adiposity are each independently associated with health outcomes among children, although the relationship between these two variables is unclear. Our objectives were to evaluate (i) the association of adiposity with aerobic fitness using objectively measured levels of percent body fat, compared to BMI as a percentile proxy for adiposity while controlling for genetic admixture, and (ii) the congruence of BMI categories with high and low body fat categories of objectively measured percent body fat. Participants were 232 African-American (AA), European-American (EA), and Hispanic-American (HA) children aged 7-12 years (Tanner stage <3). Aerobic fitness was measured via a submaximal indirect calorimetry treadmill test (VO(2-170)), and physical activity levels with accelerometry. Genetic admixture estimates were obtained using 140 genetic ancestry informative markers to estimate European, African, and Amerindian admixture. Fat mass was determined using dual-energy x-ray absorptiometry (DXA). Children were classified into a low body fat group (<25% in males, <30% in females) or a high body fat group based on their percent body fat; children were also categorized according to BMI percentile. Children in the low body fat group had significantly higher aerobic fitness (P < 0.05) regardless of BMI percentile classification. Higher African genetic admixture was associated with lower aerobic fitness (P < 0.05), while physical activity was positively associated with fitness (P < 0.01). In conclusion, aerobic fitness levels differ by percent body fat and genetic admixture irrespective of BMI classification, and such differences should be taken into account when evaluating outcomes of health interventions.
有氧适能和肥胖程度在儿童中都与健康结果独立相关，尽管这两个变量之间的关系尚不清楚。我们的目的是评估：（i）在控制遗传混合的情况下，使用客观测量的体脂百分比与 BMI 作为肥胖程度的百分位代理来评估体脂与有氧适能的关系，（ii）BMI 类别与客观测量的体脂百分比的高低体脂类别之间的一致性。参与者为 232 名 7-12 岁的非裔美国人（AA）、欧洲裔美国人（EA）和西班牙裔美国人（HA）（Tanner 分期<3）。通过亚最大间接测热跑步机测试（VO（2-170））测量有氧适能，使用加速度计测量身体活动水平。使用 140 个遗传祖先信息标记物获得遗传混合估计值，以估计欧洲、非洲和美洲印第安人的混合。使用双能 X 射线吸收法（DXA）确定脂肪量。根据他们的体脂百分比，将儿童分为低体脂组（男性<25%，女性<30%）或高体脂组；还根据 BMI 百分位数对儿童进行分类。无论 BMI 百分位分类如何，低体脂组的儿童有氧适能显著更高（P < 0.05）。较高的非洲遗传混合与较低的有氧适能相关（P < 0.05），而身体活动与健康呈正相关（P < 0.01）。总之，有氧适能水平因体脂百分比和遗传混合而不同，无论 BMI 分类如何，在评估健康干预的结果时，都应考虑到这些差异。
