Environmental factors associated with overweight and obesity in Taiwanese children

Background: We explored the relationship among sociodemographic, behavioural, household environmental and perinatal factors, and risks of childhood overweight and obesity in Taiwan. Methods: A total of 7930 children aged 9 to 14 years were recruited from 14 randomly selected Taiwanese communities in 2007 and 2010. Height and weight were measured using standard protocols during school visits. Questionnaires that contained children's family information, birth conditions, exercise habits and household environmental factors were answered by the parents. Associations between risk factors and childhood overweight and obesity were estimated through odds ratio and 95% confidence interval from mixed models. Results: In this cohort, 32.3% of the children were overweight and 17.5% were obese. Male gender, high birthweight, exposure to in utero maternal smoking and current exposure to household environmental tobacco smoke (stronger effect of maternal than paternal smoking) were positively associated with childhood overweight/obesity. In contrast, higher parental education level, number of siblings, active exercise habits and taking vitamins were associated with reduced risks of childhood obesity. Birthweight revealed a J-shaped relationship with the probability of childhood overweight/obesity. Conclusions: This study uncovers several modifiable risk factors for childhood overweight and obesity, and parents are encouraged to provide an anti-obesity environment such as quitting smoking, controlling birthweight of child during pregnancy and building up exercise habits.