Obesity among children attending Sao Paulo/Brazil elementary public schools: A case-control study

To describe obesity among students of public schools in Sao Paulo City, Brazil as well as to identify risk factors for this nutritional disorder, this case control study of obese and non-obese schoolchildren was conducted. Children were studied retrospectively on nutrition and behavior as risk factors related to obesity. 223 obese (W/H greater than or equal to 2Z) and 223 eutrophic (W/H Z > -1 and < 1) schoolchildren (7-10 years old) were identified by an anthropometric survey that included 2519 children of eight elementary public schools in Sao Paulo. Parents or guardians of the 446 cases and controls were interviewed on the children's eating behaviors and habits. Parents were weighed and measured at the end of the interview, and their BMI was calculated. The prevalence of obesity (W/H > 2Z) in the surveyed population was 10,5%. A logistic regression model fitted to the case-control data set showed that obesity was positively associated with birth weight > 3500g (Odds ratio (OR) (confidence interval 95% (IC)) = 1,83 (1,21 - 2,78), child appetite at meals 3,81 (2,49 - 5,83), watching television 4 hours or longer 2,07 (1,32 - 3,24), mothers' schooling > 4 years 1,85 (1,25 - 2,75) and parents BMI > 30Kg/m super(2) 2,50 (1,43 - 4,37). The explanatory multivariate model points to preventive measures that would encourage the knowledge of children and their guardians in relation to a balanced diet and would promote a less sedentary lifestyle such as reducing television viewing. Schoolchildren born with 3500g or more or those whose parents were obese should receive special attention in the prevention of obesity.