Petranović Matea Zajc, Tomas Zeljka, Skarić-Jurić Tatjana, Milicić Jasna, Narancić Nina Smolej
Institute for Anthropological Research, Zagreb, Croatia.
Coll Antropol. 2013 May;37 Suppl 2:131-8.
The adolescence is recognized as one of the critical periods for the development of obesity. Children and adolescents who practice sports regularly have higher muscle mass and lower percentage of body fat than their peers who are physically less active. Since body mass index (BMI) is a widely used indicator of overweight/obesity in spite of the fact that it directly measures excess in weight but not in fat, it often misclassifies athletic populations, both children and adults. The specific aim of this study was to evaluate whether BMI adequately assesses fatness in adolescents, especially physically active ones. The analysis was performed on anthropometric data from two surveys (1997 and 2009/2010) of Zagreb secondary school adolescents, 1315 girls and 1034 boys, aged 15-19 years. The group defined as "physically active" consisted of adolescents who practice organized sports (36.2% girls, 44.6% boys), while the "physically inactive" group was made of their peers who practice sport only as a part of physical education in schools. The standardized values, calculated within each sex by survey, were used for comparison of adolescents with different levels of physical activity. Physically active adolescents of both sexes had lower sum of skinfolds mean Z-valutes (Pgirls<0.05, Pboys<0.001); additionally, boys had higher Z-values for body weight (p<0.05) and triceps/subscaputar ratio (indicating peripheral distribution of body fat) (p<0.05) than their less active peers. In order to evaluate whether BMI was adequate indicator for body composition during adolescence, we estimated the concordance of above-median category defined by BMI and the other body fat indicators. The largest discrepancy was found for sum of skinfolds in both sexes and was more pronounced in physically active adolescents. This finding was further confirmed in more extreme BMI category (85th - 95th percentile) which indicated that adolescents categorized as "at risk of overweight" were predominantly characterized by larger lean body mass and not by increased fatness.
青春期被认为是肥胖发展的关键时期之一。经常进行体育锻炼的儿童和青少年比那些身体活动较少的同龄人拥有更高的肌肉量和更低的体脂百分比。尽管体重指数（BMI）直接测量的是体重超标而非脂肪超标，但它仍是广泛用于衡量超重/肥胖的指标，这常常导致对儿童和成人等运动员群体的错误分类。本研究的具体目的是评估BMI是否能充分评估青少年，尤其是身体活跃的青少年的肥胖程度。分析基于萨格勒布市中学15至19岁青少年的两次调查（1997年以及2009/2010年）中的人体测量数据，其中女生1315名，男生1034名。被定义为“身体活跃”的群体包括参加有组织体育运动的青少年（女生占36.2%，男生占44.6%），而“身体不活跃”群体则由仅在学校体育课中进行体育活动的同龄人组成。通过调查在每个性别内部计算出的标准化值，用于比较不同身体活动水平的青少年。两性中身体活跃的青少年皮褶厚度总和的平均Z值较低（女生P<0.05，男生P<0.001）；此外，男生的体重Z值（p<0.05）和三头肌/肩胛下比值（表明体脂的外周分布）（p<0.05）高于身体活动较少的同龄人。为了评估BMI是否是青春期身体成分的合适指标，我们估计了BMI定义的中位数以上类别与其他体脂指标之间的一致性。在两性中，皮褶厚度总和的差异最大，且在身体活跃的青少年中更为明显。这一发现在更极端的BMI类别（第85至95百分位数）中得到进一步证实，这表明被归类为“超重风险”的青少年主要特征是瘦体重较大，而非脂肪增加。
