Socio-economic, familial and perinatal factors associated with obesity in Sydney schoolchildren

Aim: To examine associations between socio-economic, familial and perinatal factors with overweight/obesity in 6- and 12-year-old schoolchildren. Methods: Eligible year-1 (1765/2238, mean age 6.7 years) and year-7 students (2353/3144, mean age, 12.7 years) from a random cluster sample of 55 Sydney schools were examined during 2003-2005. Height, weight and body mass index were measured. Overweight or obesity was classified using International Obesity Task Force cut points. Information about each child's socio-demographic status, familial and perinatal information was sought in parental questionnaires. Results: After multivariate adjustment, lower parental education was significantly associated with prevalent overweight and obesity in 6-year-old children, odds ratio (OR) 1.52 (95% confidence interval (CI) 1.15-2.01) and OR 2.16 (CI 1.34-4.13), respectively. Smoking during pregnancy was associated with a higher likelihood of being obese among both 6- and 12-year-old children, OR 1.90 (CI 1.05-3.46) and OR 1.78 (CI 1.22-2.61). Population attributable risk estimates indicate that 14.9% and 10.1% of prevalent cases of obesity in 12-year-old children may be attributable to being: an only child or a heavy newborn, respectively. Conclusions: We show interdependent relationships between socio-economic, familial and perinatal factors and childhood weight status. Improved understanding of these pathways may help in developing childhood obesity prevention strategies.