Assessment of anthropometric indexes of children and adolescents with Down syndrome.

Objective: To compare the agreement in the classification of the weight-for-age (W/A) and height-for-age (HA) indexes for children and adolescents with Down syndrome (DS) according to selected international reference distributions.

Methods: A cross-sectional study was carried out in children (2 to 9.9 years old) and adolescents (10 to 17.9 years old) with DS from cities in the state of Rio de Janeiro, Brazil, in 2005. The W/A and H/A indexes were classified according to the percentiles of two curves developed for individuals with DS and one distribution developed for healthy subjects. The cut-off limits applied for categorization were: below the 5th percentile (< P5) and above the 95th percentile (> 95). The weighted Kappa index was estimated to assess agreement between the classifications (p < 0.05).

Results: Information was obtained on 98 children and 40 adolescents. From 1.0 to 18.4% of the children were < P5 for W/A, and the agreement for this index was considered weak (Kappa = 0.16; 95%CI -0.03-0.34; p < 0.01); no agreement was observed between the H/A classifications. For adolescents, W/A < P5 varied from 2.5 to 5.0%; once more there was no agreement for this classification (Kappa = 0.16; 95%CI -0.15-0.48; p > 0.05). There was good agreement for the H/A index (Kappa = 1.00; 95%CI 0.23-1.00; p < 0.01).

Conclusion: There was weak agreement between classifications of anthropometric indexes according to three different distributions. The data indicated that the construction of specific curves for individuals with DS would facilitate the identification of overweight, which is often observed among these patients.