Factors associated with overweight in children living in the neighbourhoods of an urban area of Brazil.

Objective: The present study aimed to investigate the individual and family determinants of being overweight among children younger than 10 years of age.

Design: Cross-sectional survey. Direct data on children's age, food intake, physical activity, type of transportation used and anthropometric measurements, as well as the education level of the mothers, were collected by trained interviewers.

Setting: Population-based study in the city of Santos, Brazil.

Subjects: A total of 531 children under 10 years of age (302 aged <6 years, 229 aged ≥6 years), living in the city of Santos.

Results: The overall prevalence of overweight and obesity (BMI-for-age Z-score >1) was 35·4 % for children under 6 years and 38·9 % for children aged 6-10 years. The socio-economic status of the family was associated with being overweight for both age groups. Logistic regression analysis showed that the lower the socio-economic status, the higher the likelihood of being overweight, among both younger children (OR = 7·73; P = 0·02) and older children (OR = 1·98; P = 0·04). The use of active transportation was associated with a lower likelihood of being overweight, but only among younger children (OR = 1·70; P = 0·05).

Conclusions: Socio-economic status seems to be an important individual-level determinant of overweight in children. Public policies should consider promoting the use of active transportation, as the results showed it to have a positive effect on reducing overweight issues. The high prevalence of overweight in younger children suggests that this age group should be a priority in health-promoting interventions.