Don't children grow out of their obesity? Weight transitions in early childhood.

Background: Expert opinion and cross-sectional analyses posit that obese young children will likely "outgrow" their obesity. However, given the nature of the US childhood obesity epidemic, this assertion may no longer hold true.

Objective: To compare the weight transitions between early childhood (3-5 years) and midchildhood (7-10 years) in 2 different longitudinal cohorts: black preschool children from the inner city and from a nationally representative sample.

Results: Weight transitions for children who were normal weight at baseline were not markedly different between cohorts. However, overweight and obese low-income black children had a very high probability of becoming or remaining overweight or obese by follow-up (>90% probability) in comparison with the nationally representative cohort (50%-60% probability).

Conclusion: Low-income black preschool children do not necessarily "outgrow" their obesity. These findings have implications for optimal timing of obesity interventions and suggest the need for an increasing focus on children during the early preschool years.