Objective: To verify the evolution of body mass index (BMI) between two studies of adolescent populations.
Methods: Data on the BMI of 8,020 adolescents aged 10 to 15 years living in the city of São Paulo, Brazil, and enrolled on the 2005 study entitled "The nutritional profile of adolescents at public and private schools in São Paulo" were compared with data from the 1989 National Nutrition and Health Census (PNSN - Pesquisa Nacional sobre Saúde e Nutrição). Binomial testing was used to compare proportions once both data sets had been transformed into percentiles.
Results: Comparing the two surveys, significant increases were identified in 85th and 95th percentile BMI values for male adolescents aged 10 to 15 years and for female adolescents aged 10 to 14 years. Analysis of the difference between the 5th and 95th BMI percentiles of the São Paulo and PNSN samples indicates that there was probably an increase in the number of adolescents in the higher BMI ranges in São Paulo in relation to the PNSN survey.
Conclusions: These results demonstrate a tendency for the adolescents observed mean BMI values to increase during the period between the two surveys, indicating a need for increased monitoring of this measurement as a form of preventing overweight in this population.