The influence of socioeconomic status and age on the prevalence of overweight and obesity among 5 to 10-year-old children in Curitiba, Brazil

Objective The aim of this study was to examine the influence of the socioeconomic status (SES) and age on the prevalence of overweight and obesity among 5 to 10-year-old children from Brazil. Methods The sample consisted of 80 782 (41 063 boys) students aged 5 to 10-year-old. Height and weight were measured and body mass index (BMI) was calculated. SES was self-reported by parents when registering for school in the same year as the assessment. Results An increasing trend in the prevalence of obesity, for boys and girls, and overweight, for girls, as they got older was observed. The prevalence of obesity was greater among medium SES boys, 18.1% (95% CI: 17.7, 18.6), and girls, 18.1% (95% CI: 17.7, 18.6), compared with low SES. For each year boys and girls get older their odds of being underweight, overweight and obese increase. Medium and high SES boys were 23% (95% CI: 1.14, 1.32) and 25% (95%CI: 1.03, 1.52) more likely to be obese than low SES boys. Girls with high SES were 20% (OR = 1.20; 95% CI: 1.10, 1.31) more likely of being obese than girls with low SES. Furthermore, age and being in the medium SES for both sexes and in the high SES for boys was positively related to the BMI z-score. Conclusion Both age and SES were factors associated with obesity among Brazilian children. For public health policies to be effective, it is necessary to understand why higher SES children and older children have higher risk and prevalence of obesity and overweight.