Family structure and obesity in early childhood.

This study informs family and child health research by using longitudinal Fragile Families data to assess how family structure and transitions are associated with changes in children's BMI and weight status between ages three and five. Concerns in family structure literature about biases due to selectivity are reduced through the use of change score models and by controlling for parental BMI. The findings indicate unhealthy BMI gain and an increased risk of becoming overweight/obese among children living with a mother who recently dissolved a union or had been living without a partner for at least 2years compared with those in stable married parent families. Children with single mothers who entered a new union had significantly healthier BMI trajectories than those whose mothers remained single or recently became single. These results suggest the importance of two-parent family contexts for children's healthy physical development, and that single mothers may need additional support to better manage their children's BMI.