da Veiga G V, Dias P C, dos Anjos L A
Instituto de Nutrição, Universidade Federal do Rio de Janeiro, Av. Brigadeiro Trompowsky s/n, Centro de Ciências da Saúde Bloco J 2o Andar, Ilha do Fundão-Cidade Universitária, 21941-590-Rio de Janeiro, RJ, Brasil.
Rev Panam Salud Publica. 2001 Aug;10(2):79-85. doi: 10.1590/s1020-49892001000800002.
To assess the validity of recommendations for use of the 85th and 95th percentiles of body mass index (BMI) of the population in the United States of America as a screening tool to assess overweight/obesity in adolescents.
We investigated the relation between BMI and percent body fat in 1,540 adolescents (717 males and 823 females) aged 10 to 17.9 years old from a private high school in Niterói, a city in the state of Rio de Janeiro, Brazil. We used bioelectric impedance, with the appropriate equations for adolescents, to estimate percent body fat, which served as the gold standard (30% for girls and 25% for boys) to calculate the sensitivity and specificity of the 85th and 95th percentiles of the United States and Brazilian distribution curves of BMI.
Sensitivity and specificity were high (above 80%) for the Niterói boys, except for the 85th percentile of the Brazilian curve (specificity = 61.8%) and for the 95th percentile of the United States curve (sensitivity = 55.4%). For the Niterói girls, the 85th- and 95th-percentile BMI cutoff points, from both the United States and Brazilian curves, showed low sensitivity, and that sensitivity decreased with age. Specificity was high for the girls, and much higher than it was for the boys.
These data suggest that using BMI to screen for overweight/obesity in adolescents can generate a high percentage of false-positives for Niterói boys and an even higher percentage of false-negatives for Niterói girls. A more universal approach to using anthropometric measures to screen for overweight/obesity should be developed, preferably linked to stages of maturation.
评估将美国人群体重指数（BMI）的第85和第95百分位数用作筛查工具来评估青少年超重/肥胖的有效性。
我们调查了来自巴西里约热内卢州尼泰罗伊市一所私立高中的1540名10至17.9岁青少年（717名男性和823名女性）的BMI与体脂百分比之间的关系。我们使用生物电阻抗法，并采用适合青少年的公式来估算体脂百分比，该体脂百分比作为金标准（女孩为30%，男孩为25%），以计算美国和巴西BMI分布曲线的第85和第95百分位数的敏感性和特异性。
对于尼泰罗伊的男孩，除了巴西曲线的第85百分位数（特异性=61.8%）和美国曲线的第95百分位数（敏感性=55.4%）外，敏感性和特异性都很高（高于80%）。对于尼泰罗伊的女孩，美国和巴西曲线的第85和第95百分位数的BMI切点显示敏感性较低，且该敏感性随年龄降低。女孩的特异性较高，且远高于男孩。
这些数据表明，使用BMI筛查青少年超重/肥胖会导致尼泰罗伊男孩出现较高比例的假阳性，而尼泰罗伊女孩出现更高比例的假阴性。应制定一种更通用的方法，利用人体测量指标筛查超重/肥胖，最好与成熟阶段相关联。
