Childhood obesity has become a serious public health threat worldwide due to its many adverse health effects. In addition to nutritional factors and physical activity factor, several family characteristics such as number of family member, income, food expenses, and parental nutrition may also influence in childhood obesity. To examine the association of the family factors to obese children, a case-control study was conducted in 319 children (147 obese case and 172 normal nutrition controls) who were recruited from 13 primary schools in urban areas, Hanoi. The results showed that the risk of childhood obesity increased by 3.4 times when father was overweight or obesity, by 3.1 times when mother was overweight or obesity, and by 11 times when both patents were overweight or obesity (P0.0001) as compared to the children having parents with normal nutritional status
while the other characteristics including number of children, number of family member, average income and the average food expenses were not significantly associated with obesity. In conclusion, the status of overweight and obesity of parents are the significantly independent risk factor of obesity among primary school children in urban areas of Hanoi.