OBJECTIVE: This study investigated the association of obesity with metabolic and clinical variables and inactivity in post-pubertal adolescents attending public schools in São Paulo City. METHODS: This was a case-control study with 128 obese adolescents (body mass indices >the 95th percentile), and 151 normal weight adolescents (body mass indices between the 5th and 85th percentiles). Physical examination and biochemical and body composition assessments were done. A pretested questionnaire was administered, generating an inactivity score. Analysis of variance was performed with multiple comparison tests (Bonferroni and Pearson's chi-Square). A multiple regression model was used to ascertain the association among clinical variables, metabolic variables, inactivity score and nutritional status. RESULTS: Analysis of variance allowed the identification of a gradient of mean metabolic and clinical variables which worsened as activity decreased, confirmed by the chi-square test. In the bivariate analysis for obesity risk, obese adolescents were more frequently inactive, presented low high-density lipoprotein and high triglyceride levels, hyperinsulinemia, high homeostasis model assessment for insulin resistance, and high blood pressure (p<0.05). The multiple logistic model showed associations between obesity and inactivity (OR=2.23), low high-density lipoprotein levels (OR=3.05), high blood pressure (OR=3.57), high triglyceride levels (OR=4.13) and high homeostasis model assessment for insulin resistance (OR=11.65). CONCLUSION: Inactivity, low high-density lipoprotein, hypertriglyceridemia, insulin resistance and hypertension are strongly associated with obesity in adolescents. Strategies to reduce body weight by changing life habits should be part of public health programs and policies, especially for this age group.
Adolescent; Physical activity; Risk factors; Body mass index; Obesity
